ANTI-HIV DRUG INTERACTIONS. a guide to the interactions found between anti-hiv drugs and common hiv-related therapies

ANTI-HIV DRUG INTERACTIONS! a guide to the interactions found between anti-hiv drugs and common hiv-related therapies A PUBLICATION FROM Information, Inspiration and Advocacy for People Living With HIV/AIDS With the number of drugs available to treat HIV and with those that prevent or treat opportunistic infections (OIs), the potential for drug interactions increases. Developing a health management plan and deciding which therapies to include in that plan may seem a daunting task. Not only does each therapy have possible side effects, but each might increase or decrease the benefit of the other drugs you take. AUGUST 2004 Drug interactions can take various forms, occurring immediately or over several weeks. Some drugs simply should not be used together, while others can be combined only if done with careful monitoring to detect emergency problems. Interactions can also occur when one therapy alters the effect of another. This includes how the other is absorbed in the body, broken down (metabolized), distributed or excreted. A common interaction can occur when two drugs have similar side effect profiles. For example, both ddi and ddc can cause a tingling or pain in the legs, hands or feet (peripheral neuropathy). It s not recommended that they be used together because the similar side effects may increase the potential for neuropathy. Similarly, AZT and ganciclovir (a treatment for CMV) may both cause bone marrow suppression, resulting in anemia. However, adding a third drug, G-CSF (Neupogen), can help manage this interaction. In addition, higher blood levels of a drug increase the chance of more side effects. PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG

talking to your doctor about drug interactions Many people take a variety of therapies at the same time. These can range from experimental and approved anti-hiv drugs to complimentary and over-the-counter medicines. Drug interactions may play a major role in the success of any treatment plan. Unfortunately, they re not always considered when developing a treatment strategy. The following are some suggestions to help prevent drug interactions:! BROWN BAG MEDICINE CHECKUP. Each time you see your healthcare provider, put all your meds including over-the-counter and complimentary products in a bag. Take the bag with you and have your doctor review those medicines for safety, appropriateness, compatibility and instructions for use.! NEW PRESCRIPTIONS. Each time your doctor prescribes you a new medication, ask him or her if it can be combined safely with your other therapies.! REGULAR DISCUSSION. Talk to your doctor about making the medicine checkup part of your regular visits. Discuss how best to check for possible drug interactions. (Bring Project Inform s publication, Drug Interactions, with you to your appointment.) 2 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER As it has become standard medical practice to prevent multiple OIs with different drugs, drug interactions become more of a concern. In some prevention regimens, drug interactions may even cause more harm than good. For example, one drug might reduce the blood levels of another drug, leading to drug resistance. This could result in a particular disease (like HIV or hepatitis) becoming unresponsive to treatment. The added toxicity of many therapies taken together may also outweigh their hopeful benefit for preventing disease. Therefore, healthcare providers and people with HIV should make informed decisions about combining therapies and OI prevention regimens and should carefully check for drug interactions and other side effects. Unfortunately, most drug interaction studies have compared only two drugs, although most people with HIV often take many more than two. As a result, very little is known about how all the commonly used drugs interact with each other. In the meantime, it s important to discuss possible drug interactions with your doctor and pharmacist. Before starting a new therapy (experimental, approved or complimentary), consider the possible drug interactions and side effects. Not everyone experiences side effects; and many drug interactions can be managed by monitoring carefully, adjusting the doses, or stopping the therapy as needed. The following chart should only be used as a guide for possible drug interactions. Remember that these interactions might occur in some people, but not in others. This chart was put together with information from prescription package inserts, anecdotal reports, discussions with pharmacologists and doctors who treat HIV disease, and discussions with drug companies. glossary and instructions Throughout the text of drug interactions on pages 3 27, you may find terms and instructions you re not familiar with. A glossary of these terms and dosing instructions can be found on page 27. TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME

Abacavir (Ziagen) plus 3TC Decreases 3TC level by 15% in No Alcohol Increases abacavir level by 41% in Increases amprenavir level by 29% in Increases AZT level by 10% in No Chloral hydrate increase chloral hydrate Methadone May decrease methadone Check for methadone withdrawal symptoms and adjust methadone Tenofovir Although blood levels not affected, tenofovir and abacavir used in combination may speed the development of resistance to both. Acyclovir (Zovirax) plus Probenecid Increases acyclovir Adefovir (Hepsera) plus Amikacin Amphotericin B Cidofovir Foscarnet Gentamicin Ibuprofen Increases adefovir level by 23% in blood and may increase risk Kanamycin NSAIDS risk Pentamidine (IV) Tenofovir Adefovir plus (continued) Tobramycin Amphotericin B (Fungizone) plus Adefovir Should not be used together.* Increases risk Amikacin May increase risk Anticancer drugs May increase risk of kidney toxicity and low blood pressure. Cidofovir Clotrimazole May interfere with the activity of amphotericin B. Corticosteroids decrease potassium level and increases risk of heart problems. Cyclosporine May increase risk ddc May increase ddc level in blood and increase risk of peripheral neuropathy. Digitalis Use together with great caution. May increase risk of heart problems. Fluconazole May interfere with the activity of amphotericin B. Flucytosine Increases antifungal activity in test tubes but also increases risk of bone marrow and kidney toxicity. Foscarnet May decrease number of red blood cells and increases risk Ganciclovir Gentamicin May increase risk May interfere with the activity of amphotericin B. Kanamycin May increase risk May interfere with the activity of amphotericin B. Amphotericin B plus (continued) Miconazole May interfere with the activity of amphotericin B. Pentamidine (IV) May increase risk Tenofovir risk Tobramycin May increase risk Amprenavir (Agenerase) plus Abacavir Increases amprenavir level by 29% in Alcohol Should not be used together. Alcohol and the oral formulation of amprenavir increases risk Alprazolam May increase alprazolam Amiodarone increase risk Requires monitoring concentration of amiodarone. Antacids Amprenavir should be taken 1 hour before or 1 hour after taking antacids. Astemizole Should not be used together*. Increases risk Atazanavir Atazanavir may increase amprenavir levels in Atorvastatin May increase atorvastatin Increases AZT level by 31% and increases amprenavir level by 13% in No Bepridil Should not be used together*. Increases risk Carbamazepine May decrease amprenavir Cimetidine May increase amprenavir Cisapride Should not be used together*. Increases risk Clarithromycin Increases amprenavir level by 18% in No dose adjustment recommended. Clorazepate May increase clorazepate Clozapine May increase clozapine D R UG INTERA CTIO NS. AUGUS UGUST 2004. PR O JECT INFORM 3 PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG

4 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER Amprenavir plus (continued) Dapsone May increase dapsone Should be taken 1 hour before or after taking ddi tablets. ddi EC may be taken at the same time as amprenavir, but only on an empty stomach. May increase amprenavir Diazepam May increase diazepam Dihydroergotamine Diltiazem May increase diltiazem Disulfiram Should not be used together with amprenavir oral solution*. Increases risk Efavirenz Decreases amprenavir level by 36% and increases efavirenz level by 15% in Amprenavir dose may need to be increased. Ergotamine Erythromycin May increase erythromycin and amprenavir levels in Ethinyl estradiol Should not be used together. Amprenavir may decrease ethinyl estradiol and norethindrone levels in Use another form of contraception. Felodipine May increase felodipine Flurazepam May increase flurazepam (high fat) Decreases amprenavir level in blood and should be avoided. Increases amprenavir level by 33% and decreases indinavir level by 38% in May increase itraconazole and amprenavir Check for toxicity. Decreases lopinavir level by 15% and increases amprenavir trough level about 2- fold in Amprenavir dose should be reduced to 750mg twice a day or less. However, optimal dose is unclear. Increases amprenavir level by 31% and increases ketoconazole level by 44% in Impact of interaction is uncertain. Lidocaine (systemic) Requires monitoring concentration of lidocaine. Loratidine May increase loratidine Amprenavir plus (continued) Lovastatin May increase lovastatin Metronidazole Should not be used together with amprenavir oral solution*. Increases risk Midazolam Increases nelfinavir level by 15% in May decrease amprenavir Dose of amprenavir may need to be increased. Norethindrone Should not be used together. Amprenavir may decrease ethinyl estradiol and norethindrone levels in Use another form of contraception. Nicardipine May increase nicardipine Nifedipine May increase nifedipine Nimodipine May increase nimodipine Phenobarbital decrease amprenavir decrease amprenavir Pimozide May increase pimozide Pravastatin May increase pravastatin Quinidine Requires monitoring concentration of quinidine. Decreases amprenavir level by 15% and increases rifabutin level by 193% in A lower dose of rifabutin required. Should not be used together*. Significantly decreases amprenavir Increases amprenavir level by 70% in Alternate dosing is amprenavir 600mg + ritonavir 100mg twice a day, or amprenavir 1,200mg + ritonavir 200mg once daily. Decreases amprenavir level by 32% and saquinavir level by 19% in No dose adjustment likely required. Sildenafil increase sildenafil Simvastatin May increase simvastatin Amprenavir plus (continued) St. John s Wort May significantly decrease amprenavir level in Tedalafil increase tedalafil Tricyclic antidepressants Requires monitoring concentration of tricyclic antidepressants. Vardenafil increase vardenafil Vitamin E Amprenavir capsules contain more than the recommended daily allowance for vitamin E. Additional supplementation, especially when used together with drugs like warfarin could result in hemorrhage. Warfarin Requires monitoring concentration of warfarin. Atazanavir (Reyataz) plus Amiodarone Increases risk Check amiodarone level and use with caution. Atazanavir may increase amprenavir levels in Antacids May decrease atazanavir Take atazanavir 2 hours before or 1 hour after taking antacids. Atorvastatin May increase risk Bepridil Calcium channel blockers Decrease dose of calcium channel blockers and check ECG. Cisapride Clarithromycin Increases risk of side effects and may decrease effectiveness of clarithromycin. Consider alternatives or reduce clarithromycin dose by at least 50%. Cyclosporin Check cyclosporine level. TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME

Atazanavair plus (continued) ddi buffered tablets can significantly decrease atazanavir Take atazanavir (with food) either 2 hours before or 1 hour after buffered ddi tablets. Although ddi EC should not affect atazanavir level, they should be taken at least 1 hour apart. Atazanavir should be taken with food, and ddi EC should be taken on an empty stomach. Diltiazem Decrease diltiazem dose by at least 50% and check ECG. Ergot derivatives Efavirenz Decreases atazanavir Atazanavir should be boosted with ritonavir if used with efavirenz. Ethinyl estradiol Atazanavir increases ethinyl estradiol Use lowest effective ethinyl estradiol dose. High fat meal increases atazanavir by 35% and low fat meal increases atazanavir level by 70% in Atazanavir should be taken with food. Irinotecan Atazanavir may interfere with irinotecan metabolism. May increase irinotecan side effects. Lidocaine (systemic) Increases risk Check lidocaine level and use with caution. Lovastatin Midazolam Norethindrone Should be used together with caution and decrease norethindrone dose to lowest effective dose. May increase norethindrone side effects, particularly in diabetic women. Pimozide Proton-pump inhibitors Should not be used together. May significantly decrease atazanavir Quinidine Increases risk Check quinidine level and use with caution. Increases rifabutin level. Decrease dose of rifabutin to 150mg every other day or 3 times a week. level of most protease inhibitors in Atazanavair plus (continued) Substantially increases atazanavir blood level. If combined, use atazanavir 300mg (with food) + ritonavir 100mg once daily. Increases saquinavir level by 5 6 fold in Dose adjustments currently under study. Sildenafil Increases sildenafil blood level. Decrease sildenafil dose to 25mg every 48 hrs and check Simvastatin Sirolimus Check sirolimus level. St. John s Wort Should not be used together. May reduce atazanavir Tacrolimus Check tacrolimus level. Tedalafil increase tedalafil Tenofovir Increases tenofovir level by 24% and decreases atazanavir level by up to 40% in Atazanavir should be boosted with ritonavir if used with tenofovir. Tricyclic antidepressants Increases risk Check antidepressant level and use with caution. Vardenafil increase vardenafil Warfarin Has not been studied but may lead to serious side effects. Atovaquone (Mepron) plus Increases AZT level by 35% in No Fatty foods Increases atovaquone Atovaquone should be taken with food. Decreases atovaquone Atovaquone dose may have to be increased. decrease atovaquone Decreases atovaquone level by 50% in May decrease atovaquone Atovaquone plus (continued) TMP/SMX Increases TMP/SMX blood level by 17% and 8%, respectively. No dose adjustment recommended. Azithromycin (Zithromax) plus May increase AZT No dose adjustment recommended. Cyclosporine May increase cyclosporine May increase ddi No dose adjustment recommended. Digoxin May increase digoxin Ergot derivatives May increase ergot drug Azithromycin may be taken with or without food. Hexobarbital May increase hexobarbital Midazolam May increase midazolam No Increases azithromycin No dose adjustment recommended, but check for hearing and liver side effects. May increase phenytoin May increase rifabutin No Theophylline May increase theophylline Terfenadine May increase terfenadine Warfarin May increase warfarin Birth control pills See section on Ethinyl estradiol. Cidofovir (Vistide) plus Adefovir Amikacin Amphotericin B Foscarnet D R UG INTERA CTIO NS. AUGUS UGUST 2004. PR O JECT INFORM 5 PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG

6 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER Cidofovir plus (continued) Gentamicin Kanamycin Pentamidine (IV) Probenecid Needs to be taken together to decrease the risk Streptomycin Increases risk Tenofovir risk Tobramycin Ciprofloxacin (Cipro) plus Antacids Needs to be taken 2 hours before or 6 hours after taking ciprofloxacin, otherwise decreases ciprofloxacin Caffeine May increase caffeine Cyclosporine May increase risk of elevated serum creatinine. Ciprofloxacin needs to be taken 2 hours before or 6 hours after ddi buffered tablets, otherwise ddi may decrease ciprofloxacin Ciprofloxacin may be taken at the same time as ddi EC capsules. May be taken with or without food, but preferred time of dosing is 2 hours after a meal. Iron supplements Needs to be taken 2 hours before or 6 hours after taking ciprofloxacin, otherwise decreases ciprofloxacin Methotrexate May increase blood level of methotrexate. If used together, check for methotrexate side effects. Probenecid Increases ciprofloxacin Sucralfate Needs to be taken 2 hours before or 6 hours after taking ciprofloxacin, otherwise decreases ciprofloxacin Theophylline Should not be used together.* Increases risk of serious side effects. If concurrent use cannot be avoided, check theophylline level and adjust dose. Warfarin May increase warfarin Check for warfarin toxicity. Ciprofloxacin plus (continued) Zinc-containing multivitamins Needs to be taken 2 hours before or 6 hours after taking ciprofloxacin otherwise decreases ciprofloxacin Clarithromycin (Biaxin) plus Alprazolam May increase midazolam blood level. Check for alprazolam side effects. Increases amprenavir level by 18% in Anticoagulants May increase anticoagulants effect. Check prothrombin (coagulation) time. Astemizole risk of heart problems. Atazanavir Increases risk of side effects and may decrease clarithromycin effectiveness. Consider alternatives or reduce clarithromycin dose by at least 50%. Atorvastatin May increase risk of atorvastatin side effects. Decreases AZT level by 25% in Consider taking at least 2 hours apart. Carbamazepine Increases carbamazepine Check carbamazepine level. Cisapride Cyclosporine May increase cyclosporine Interaction is complex. Clarithromycin dose should be adjusted for people with kidney problems. Digoxin May increase digoxin Check digoxin level. Disopyramide May increase risk Check disopyramide level and QTc prolongation. Efavirenz Slightly increases efavirenz level but decreases clarithromycin level by 39% (increases 14- OH clarithromycin level by 34%) in No dose adjustment currently recommended. Ergot derivatives increase risk for serious side effects. Fluvastatin May increase risk of fluvastatin side effects. Increases clarithromycin level by 53% and indinavir level by 29% in No dose adjustment recommended. Increases clarithromycin Clarithromycin dose should be decreased for people with kidney dysfunction. Clarithromycin plus (continued) Loratadine May affect loratidine and clarithromycin levels in No dose adjustment currently recommended. Lovastatin May increase risk of lovastatin side effects. Midazolam May increase midazolam blood level. Check for midazolam side effects. Consider using alternatives to clarithromycin. Decreases clarithromycin level by 30% and increases nevirapine level by 26% in Pimozide Should not be used together.* Increases risk of serious side effects. May increase phenytoin Pravastatin May increase risk of pravastatin side effects. Quinidine May increase risk Check quinidine level and QTc prolongation. increase rifabutin level and decrease clarithromycin decrease clarithromycin Increases clarithromycin level by 77% and increases ritonavir level by 12% in Requires lower dose of clarithromycin and monitoring for kidney toxicity in people with a history of kidney problems. Increases saquinavir level by 177% and increases clarithromycin level by 45% (but decreases 14-OH clarithromycin level by 24%) in No dose adjustments currently recommended. Sildenafil May increase sildenafil Consider dose reduction. Simvastatin May increase risk of simvastatin side effects. St. John s Wort May decrease clarithromycin Tedalafil increase tedalafil Theophylline Increases theophylline Check theophylline level. May increase triazolam Check for triazolam side effects. Trimetrexate May affect trimetrexate and/or clarithromycin TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME

Clarithromycin plus (continued) Vardenafil increase vardenafil Warfarin Check prothrombin (coagulation) time. Clindamycin (Cleocin) plus Erythromycin Should not be used together*. Causes erythromycin and clindamycin to be less effective. Neuromuscular blocking agents May increase neuromuscular blocking effect. Clofazimine (Lamprene) plus Dapsone May decrease effectiveness of clofazimine. Combivir plus Combivir is a single pill containing 2 anti- HIV drugs AZT and 3TC. If you take Combivir as part of your regimen, refer separately to drug interactions for AZT and 3TC. Cycloserine (Seromycin) plus Alcohol May increase risk of seizures. Ethionamide May increase risk of central nervous system related toxicity. Isoniazid May increase risk of central nervous system related toxicity. Dapsone plus May increase dapsone Clofazimine May decrease effectiveness of clofazimine. ddc ddi ddi buffered tablets and dapsone need to be taken 2 hours apart, otherwise dapsone has no activity. Ganciclovir Probenecid increase dapsone level in blood and increase risk Pyrimethamine decrease dapsone Dapsone plus (continued) Decreases dapsone level 7 10 times in Saquinavir (Invirase) May increase dapsone Check for dapsone toxicity. TMP/SMX Increases trimethoprim level by 1.5 times; increases dapsone level by 1.5 times in Delavirdine (Rescriptor) plus Alprazolam Amlodipine increase amlodipine Check for toxicity. Amphetamines increase amphetamine May increase amprenavir Antacids Needs to be taken 1 hour apart, otherwise decreases delavirdine level by 44% in Astemizole Atorvastatin Use lowest possible dose of atorvastatin. May increase risk Barbiturates May decrease delavirdine Bepridil increase bepridil level in blood and side effects. Carbamazepine Should not be used together. May significantly decrease delavirdine Cimetidine decrease delavirdine Cisapride Clarithromycin Increases delavirdine level by 31% and increases clarithromycin level by 100% (but decreases 14-OH clarithromycin level by 75%) in Clarithromycin dose should be adjusted for people with kidney problems. Cyclosporine increase cyclosporine Check cyclosporine level. Needs to be taken 1 hour apart, otherwise decreases delavirdine Delavirdine plus (continued) Dexamethazone decrease delavirdine Dihydroergotamine Diltiazem increase diltiazem Check for toxicity. Ergonovine Ergotamine Erythromycin May increase delavirdine Ethinyl estradiol May increase ethinyl estradiol Impact of interaction is uncertain. Famotidine decrease delavirdine Felodipine increase felodipine Check for toxicity. Flecainide Check flecainide level. Fluoxetine Increases delavirdine level by 50% in Fluvastatin Use lowest possible dose of fluvastatin. May increase risk Fosamprenavir Should not be used together. May significantly decrease fosamprenavir Increases indinavir level 50 100% in Indinavir may be reduced to 600mg 3 times a day. Isradipine increase isradipine Check for toxicity. May increase delavirdine May increase lopinavir Needs further study. Increases delavirdine level by 50% in Lansoprazole decrease delavirdine Lidocaine (systemic) Check lidocaine level. Loratadine increase loratadine D R UG INTERA CTIO NS. AUGUS UGUST 2004. PR O JECT INFORM 7 PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG

8 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER Delavirdine plus (continued) Lovastatin Methadone Increases methadone May require lower dose of methadone. Methylergonovine Midazolam Increases nelfinavir level about 100% but decreases nelfinavir active metabolite by about 45%. Decreases delavirdine level by about 40% in No data exist to guide dose adjustments. Nicardipine increase nicardipine Check for toxicity. Nifedipine increase nifedipine Check for toxicity. Nisoldipine increase nisoldipine Check for toxicity. Nizatidine decrease delavirdine Omeprazole decrease delavirdine Phenobarbital Should not be used together. May significantly decrease delavirdine Should not be used together. May significantly decrease delavirdine Pimozide Propafenone Check propafenone level. Quinidine Check quinidine level. Ranitidine decrease delavirdine Rapamycin increase rapamycin Check rapamycin level. Should not be used together*. Significantly decreases delavirdine level and increases rifabutin Should not be used together*, otherwise significantly decreases delavirdine Delavirdine plus (continued) Increases ritonavir level by about 70% in No dose adjustment currently recommended. Increases saquinavir level by 5 times in Decrease saquinavir dose to 800mg 3 times a day. Saquinavir (Invirase) Increases saquinavir level by 5 times in May increase risk of gastrointestinal side effects and liver function tests. Decrease saquinavir dose to 800mg 3 times a day. Sildenafil Increases sildenafil Decrease sildenafil dose to no more than 25mg in a 48 hour period. Simvastatin St. John s Wort Should not be used together. May significantly decrease delavirdine Tacrolimus increase tacrolimus Check tacrolimus level. Tedalafil increase tedalafil Vardenafil increase vardenafil Verapamil increase verapamil Check for toxicity. Voriconazole increase delavirdine side effects and decrease effectiveness of voriconazole. Warfarin Check INR. Didanosine (ddi, Videx) or (ddi EC, Videx EC) plus EC stands for Enteric Coated. Alcohol Heavy alcohol intake may increase risk of pancreatitis. Allopurinol Should not be used together. Increases ddi level 113 312% in Should be taken 2 hours before or 1 hour after taking ddi tablets. ddi EC may be taken at the same time as amprenavir, but only on an empty stomach. Didanosine plus (continued) Atazanavir ddi buffered tablets can significantly decrease atazanavir Take atazanavir (with food) either 2 hours before or 1 hour after buffered ddi tablets. Although ddi EC should not affect atazanavir level, they should be taken at least 1 hour apart. Atazanavir should be taken with food and ddi EC should be taken on an empty stomach. Anticancer drugs Azithromycin May increase AZT No dose adjustment recommended. Cimetidine Needs to be taken at least 2 hours apart. Ciprofloxacin Ciprofloxacin needs to be taken 2 hours before or 6 hours after ddi buffered tablets, otherwise ddi may decrease ciprofloxacin Ciprofloxacin may be taken at the same time as ddi EC capsules. Dapsone Needs to be taken 2 hours apart, otherwise dapsone has no activity. ddc Should not be used together. Significantly increases risk of peripheral neuropathy. Needs to be taken 1 hour apart, otherwise decreases delavirdine d4t Increases risk of pancreatitis, especially in pregnant women. Decreases ddi ddi and ddi EC should be taken on an empty stomach, at least 2 hours after eating. Ganciclovir Should be used with caution. Significantly increases ddi May increase risk of pancreatitis. Hydroxyurea Increases anti-hiv activity in test tubes. May increase risk of pancreatitis. May decrease ddi and indinavir levels in Indinavir should be taken 1 hour before or 2 hours after taking ddi. Needs to be taken 2 hours apart, otherwise ddi buffering agents may significantly decrease itraconazole ddi or ddi EC should be taken 1 hour before or 2 hours after taking Kaletra. ddi and ddi EC should be taken on an empty stomach, and Kaletra should be taken with a meal. Needs to be taken 2 hours apart, otherwise ddi buffering agents may significantly decrease ketoconazole Methadone Decreases ddi level by 60% in TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME

Didanosine plus (continued) Nelfinavir should be taken 2 hours before or after taking ddi or ddi EC. Nelfinavir should be taken with food, and ddi and ddi EC should only be taken on an empty stomach. Pentamidine (IV) May increase risk of pancreatitis. Quinolones Quinolones need to be taken 2 hours before or 6 hours after ddi buffered tablets, otherwise ddi may decrease quinolone level in Quinolones may be taken at the same time as ddi EC capsules. Ribavirin of pancreatitis and mitochondrial toxicity. Decreases ddi level by 13% in No dose adjustment recommended, but take 2½ hours apart. Saquinavir Saquinavir should be taken 2 hours before or after taking ddi or ddi EC. Saquinavir is best taken with food, and ddi and ddi EC should only be taken on an empty stomach. Tenofovir Increases ddi level by 44% in May increase risk of ddi side effects. Tetracyclines risk of pancreatitis. Efavirenz (Sustiva) plus Decreases amprenavir level by 36% and increases efavirenz level by 15% in Amprenavir dose may need to be increased. Atazanavir Decreases atazanavir Atazanavir should be boosted with ritonavir if used with efavirenz. Atorvastatin Decreases atorvastatin Atorvastatin dose may need to be increased. Clarithromycin Slightly increases efavirenz level but decreases clarithromycin level by 39% (increases 14- OH clarithromycin level by 34%) in No dose adjustment currently recommended. Fluconazole Increases efavirenz level by 16% in No dose adjustment currently recommended. Should be taken on an empty stomach. Increases efavirenz level 10 50% in Fosamprenavir May significantly decrease fosamprenavir level in Use only boosted fosamprenavir at 1,400mg + 300mg ritonavir once a day. Decreases indinavir level by 31% in Indinavir dose should be increased to 1,000mg 3 times a day or 800mg twice daily if boosted with ritonavir. Efavirenz plus (continued) Decreases lopinavir level by about 25% (trough by about 33%). Kaletra dose should be increased to 4 capsules twice a day. Methadone Decreases methadone level by 52% in Check for methadone withdrawal symptoms and adjust methadone Increases nelfinavir level by 20% and decreases efavirenz level by 22% in No dose adjustments currently recommended. Decreases efavirenz level by 22% in Efavirenz dose may need to be increased to 800mg once a day. Decreases rifabutin Increase rifabutin dose by 50% if taken daily or double the dose if taken 3 times a week. Decreases efavirenz level by 26% in Impact of interaction is uncertain. Increases efavirenz level by 21% and ritonavir level by 18% in Check Decreases efavirenz level by 12% and decreases saquinavir level by 62% in Requires ritonavir boosting. St. John s Wort May decrease efavirenz Simvastatin Decreases simvastatin Simvastatin dose may need to be increased. Voriconazole Emtricitabine (FTC, Emtriva) plus There are currently no known or suspected interactions between FTC and any other drugs. Enfuvirtide (T20, Fuzeon) plus There are currently no known or suspected interactions between enfuvirtide and any other drugs, although ritonavir can increase enfuvirtide level in blood somewhat. Ethinyl estradiol (Ortho-Novum) plus ethinyl estradiol and norethindrone levels in Use another form of contraception. Atazanavir Increases ethinyl estradiol Use lowest effective dose of ethinyl estradiol. May increase ethinyl estradiol Impact of interaction is uncertain. Ethinyl estradiol plus (continued) Fluconazole Increases ethinyl estradiol level by up to 38% in No dose adjustments currently recommended. Increases ethinyl estradiol level by 24% in ethinyl estradiol level by 42% in Use another form of contraception. ethinyl estradiol level by 47% in Use another form of contraception. ethinyl estradiol Use another form of contraception. ethinyl estradiol Use another form of contraception. ethinyl estradiol Use another form of contraception. ethinyl estradiol level by 40% in Use an another form of contraception. Ethionamide (Trecator) plus Alcohol Excessive alcohol consumption while on ethionamide may cause psychosis. Cycloserine May increase risk of central nervous system related toxicity. ddc Ethambutol May increase risk of side effects from other anti-tb drugs like ethambutol. Isoniazid May increase risk of encephalopathy (dysfunction of brain). May increase isoniazid Pyrazinamide May increase risk of side effects from other anti-tb drugs like pyrazinamide. May increase risk of side effects from other anti-tb drugs like rifabutin. May increase risk of side effects from other anti-tb drugs like rifampin. Rifapentine May increase risk of side effects from other anti-tb drugs like rifapentine. Fluconazole (Diflucan) plus Amphotericin B May interfere with the activity of amphotericin B. PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG D R UG INTERA CTIO NS. AUGUS UGUST 2004. PR O JECT INFORM 9

10 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER Fluconazole plus (continued) Astemizole Increases AZT level by 74% and may increase fluconazole Check for toxicity. Benzodiazepines May increase benzodiazepine Cimetidine Decreases fluconazole level by 13% in Cisapride Cyclosporine Increases cyclosporine level by 92% in Check cyclosporine level and serum creatinine. Efavirenz Increases efavirenz level by 16% in No dose adjustment currently recommended. Ethinyl estradiol Increases ethinyl estradiol level by up to 38% in No dose adjustments currently recommended. Glipizide Increases glipizide level by 49% in Closely check blood sugar for hypoglycemia. Glyburide Increases glyburide level by 44% in Closely check blood sugar for hypoglycemia. Hydrochlorothiazide Increases fluconazole level by 45% in Decreases indinavir level by 19% in Levonorgestrel Increases levonorgestrel level by 25% in Loratadine May affect loratadine and/or fluconazole Increases phenytoin level by 88% in Ranitidine May decrease fluconazole increase rifabutin level by up to 80% in Increases risk of painful eye inflammation. Decreases fluconazole level by 23% in May require higher dose of fluconazole. Increases ritonavir level by 12% in No dose adjustment recommended; however, check for liver toxicity. May increase saquinavir However, no Saquinavir (Invirase) May increase saquinavir However, Fluconazole plus (continued) Tacrolimus increase tacrolimus level in blood and increases risk Theophylline Increases theophylline level by 21% in Check theophylline level. Tolbutamide Increases tolbutamide level by 26% in Closely check blood sugar for hypoglycemia. Trimetrexate May affect trimetrexate and/or fluconazole Warfarin Check for increases in prothrombin (coagulation) time. Flucytosine (Ancobon) plus Amphotericin B Increases antifungal activity in test tubes but increases risk of bone marrow and kidney toxicity. Cytosine arabinoside Should be used with caution. May decrease antifungal activity. Ganciclovir Interferon-alfa Fosamprenavir (Lexiva) plus Alprazolam require decrease in alprazolam dose. Amiodarone May increase serious side effects. Check amiodarone blood concentrations if possible. Atorvastatin Fosamprenavir alone and with ritonavir increases atorvastatin Lower atorvastatin dose to no more than 20mg/ day or use alternatives. Bepridil Increases risk of serious side effects. Calcium channel blockers Check Carbamazepine May significantly decrease fosamprenavir Clorazepate require decrease in clorazepate dose. Fosamprenavir plus (continued) Cimetidine decrease fosamprenavir No dose adjustment currently recommended. Cisapride of serious side effects. Cyclosporine increase cyclosporine Check cyclosporine level if used together. Should not be used together. May significantly decrease fosamprenavir blood level. Dexamethazone May significantly decrease fosamprenavir Diazepam require decrease in diazepam dose. Dihydroergotamine Efavirenz May significantly decrease fosamprenavir level in Use only boosted fosamprenavir at 1,400mg + 300mg ritonavir once a day. Ergonovine Ergotamine Famotidine decrease fosamprenavir No dose adjustment currently recommended. Flecainide Should not be used together if boosting with ritonavir*. Increases risk of serious side effects. Flurazepam require decrease in flurazepam dose. Increases risk of serious side effects. Do not exceed 400mg of itraconazole if fosamprenavir used alone, or 200mg if boosted with ritonavir. Significantly decreases fosamprenavir level in Also increases risk Appropriate dose adjustments not yet established. Increases risk of serious side effects. Do not exceed 400mg of ketoconazole if fosamprenavir used alone, or 200mg if boosted with ritonavir. Lidocaine (systemic) May increase serious side effects. Check lidocaine blood concentrations if possible. TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME

Fosamprenavir plus (continued) Lovastatin of serious side effects. Methylergonovine of serious side effects. Midazolam of serious side effects. Nizatidine decrease fosamprenavir No dose adjustment currently recommended. Phenobarbital Pimozide of serious side effects. Propafenone Should not be used together if boosting with ritonavir*. Increases risk of serious side effects. Proton pump inhibitors May significantly decrease fosamprenavir Quinidine May increase serious side effects. Check quinidine blood concentrations if possible. Ranitidine Decreases fosamprenavir level by 51% in No dose adjustment currently recommended. Rapamycin increase rapamycin Check rapamycin level if used together. Increases risk of neutropenia. Check for side effects and decrease rifabutin dose by at least 50% if fosamprenavir used alone or by 75% if boosted with ritonavir. Should not be used together*. May decrease anti-hiv effect of fosamprenavir. Increases fosamprenavir Adjust dose to fosamprenavir 700mg + ritonavir 100mg twice a day or fosamprenavir 1,400mg + ritonavir 200mg once a day. Sildenafil May increase risk Decrease sildenafil dose to 25mg every 48 hours and check Simvastatin of serious side effects. St. John s Wort Should not be used together. May significantly decrease fosamprenavir Fosamprenavir plus (continued) Tacrolimus increase tacrolimus Check tacrolimus level if used together. Tedalafil increase tedalafil of serious side effects. Tricyclic antidepressants May increase risk Check tricyclics level if used together. Vardenafil May increase risk Decrease vardenafil dose to 2.5mg/24 hours (if fosamprenavir used alone) or 2.5mg/72 hours (if boosted with ritonavir). Check Warfarin May increase risk of serious side effects. Foscarnet (Foscavir) plus Adefovir Should not be used together.* Increases risk Amikacin Amphotericin B May decrease number of red blood cells and increases risk increase risk of anemia. Cidofovir ddc May increase risk of kidney toxicity and peripheral neuropathy. Check for toxicity. Gentamicin Kanamycin Pentamidine (IV) Should be used with caution. May increase risk Check closely. Should be used with caution. Abnormal kidney function has been observed. Streptomycin Increases risk Tenofovir May increase risk Foscarnet plus (continued) Tobramycin Ganciclovir (Cytovene, oral/iv) plus Acyclovir People allergic to acyclovir should not take ganciclovir. Adriamycin Amphotericin B Anticancer drugs Increases AZT level in blood and may increase risk of neutropenia, anemia and bone marrow toxicity. Avoid combination or lower AZT dose. Dapsone Should be used with caution. Significantly increases ddi May increase risk of pancreatitis. d4t May increase risk of pancreatitis. Increases oral ganciclovir Flucytosine Imipenem-cilastin May increase risk of seizures. Check closely. Interferon-alfa Pentamidine Probenecid increase ganciclovir level in blood and decrease ganciclovir clearance. Tenofovir May increase risk Check for kidney toxicity. TMP/SMX Vinblastine Vincristine D R UG INTERA CTIO NS. AUGUS UGUST 2004. PR O JECT INFORM 11 PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG

12 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER Indinavir (Crixivan) plus Amlodipine May increase amlodipine Increases amprenavir level by 33% and decreases indinavir level by 38% in Astemizole Atorvastatin May increase atorvastatin Atazanavir Increases AZT level 17 36% in No Benzodiazepines May increase benzodiazepine Bepridil May increase bepridil Cisapride Clarithromycin Increases clarithromycin level by 53% and indinavir level by 29% in No dose adjustment recommended. ddi May decrease ddi and indinavir levels in Indinavir should be taken 1 hour before or 2 hours after taking ddi. Increases indinavir level 50 100% in Indinavir may be reduced to 600mg 3 times a day. Dihydroergotamine Diltiazem May increase diltiazem Efavirenz Decreases indinavir level by 31% in Indinavir dose should be increased to 1,000mg 3 times a day or 800mg twice daily if boosted with ritonavir. Ergonovine Ergotamine Ethinyl estradiol Increases ethinyl estradiol level by 24% in Fatty foods Decreases indinavir Indinavir should be taken 1 hour before eating or 2 hours after eating a large or fatty meal. Indinavir may be taken with a small snack such as juice and dry toast. Indinavir plus (continued) Felodipine May increase felodipine Fluconazole Decreases indinavir level by 19% in Fluvastatin May increase fluvastatin Grapefruit juice Decreases indinavir level by 26% in Isradipine May increase isradipine May affect indinavir and/or itraconazole Decrease dose of indinavir to 600mg 3 times a day when combined with itraconazole 200mg twice daily. Increases indinavir trough level by about 4- fold in Currently under study; however, indinavir dose should be reduced to no more than 600mg twice a day if used together. Increases indinavir level by 68% in Decrease indinavir dose to 600mg 3 times a day. Lovastatin Methylergonovine Midazolam Increases indinavir level by 51% and increases nelfinavir level by 83% in There are limited data to support a dose of indinavir 1,200mg + nelfinavir 1,250mg twice a day. Decreases indinavir level by 27% in Indinavir dose should be increased to 1,000mg 3 times a day or 800mg twice daily if boosted with ritonavir. Nicardipine May increase nicardipine Nifedipine May increase nifedipine Nimodipine May increase nimodipine Nisoldipine May increase nisoldipine Nitrendipine May increase nitrendipine Norethindrone Increases norethindrone level in blood by 14%. Indinavir plus (continued) Quinidine Increases indinavir level by 10% in Increases rifabutin level by 204% and decreases indinavir level by 32% in Decrease dose of rifabutin by half the standard dose and increase indinavir dose to 1,000mg 3 times a day. rifampin Rifampicin indinavir level by 80% in blood, even when boosted with ritonavir. Significantly increases indinavir level in Adjust dose to indinavir 800mg + ritonavir 200mg twice a day or indinavir 400mg + ritonavir 400mg twice a day. Increases saquinavir level 3.6 6.2 times in Saquinavir (Invirase) Increases saquinavir level 4.6 7.2 times in Sildenafil Should be used with caution. Increases indinavir and sildenafil levels in Simvastatin St. John s Wort indinavir level by 57% in Tedalafil increase tedalafil TMP/SMX Increases trimethoprim level by 31% in Vardenafil Increases vardenafil Dose of vardenafil should not exceed 2.5mg/day. Verapamil May increase verapamil Interferon-alfa (Intron-A, Roferon-A) plus Anticancer drugs Increases anti-hiv activity in test tubes and may increase risk of bone marrow toxicity. Lower AZT dose by 50 75%. Flucytosine Ganciclovir TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME

Interferon-alfa plus (continued) Pentamidine Pyrimethamine Isoniazid (INH) plus Acetaminophen Alcohol Daily or heavy alcohol use may increase risk of isoniazid-associated hepatitis. Carbamazepine Increases carbamazepine Check for toxicity and adjust carbamazepine Corticosteroids Increases isoniazid metabolism and decreases isoniazid Isoniazid dose may require adjustment. Cycloserine May increase risk of central nervous system toxicity. ddc Ethionamide May increase risk of encephalopathy (dysfunction of the brain) and may increase isoniazid isoniazid May decrease itraconazole Should not be used together*. Decreases ketoconazole Increases phenytoin Check for toxicity and adjust dose of phenytoin accordingly. increase risk of liver toxicity. Sulfonylureas May increase risk of high blood sugar level. Theophylline Increases level of theophylline in Check theophylline level closely. Itraconazole (Sporanox) plus Alprazolam increase level of alprazolam in Check Amphotericin B May interfere with activity of amphotericin B. Itraconazole plus (continued) May increase itraconazole and amprenavir levels in Check Antacids Decreases itraconazole Should be taken 2 hours apart. Astemizole Atorvastatin Busulfan Increases busulfan Check for toxicity. Carbamazepine Increases carbamazepine level and decreases itraconazole Check for side effects. Cimetidine Decreases itraconazole May need to be taken at least 2 hours apart. Cisapride Cola beverage Increases itraconazole level 75% in Cyclosporine Increases cyclosporine level in blood and may increase risk ddi Needs to be taken 2 hours apart, otherwise ddi buffering agents may significantly decrease itraconazole May increase delavirdine Diazepam increase level of diazepam in Check Digoxin Increases digoxin Check for side effects. Dofetilide Should not be used together*. Increases dofetilide Felodipine Increases risk of felodipine side effects. Check closely. Fluvastatin May increase itraconazole Fosamprenavir Increases risk of serious side effects. Do not exceed 400mg of itraconazole if fosamprenavir used alone, or 200mg if boosted with ritonavir. Itraconazole plus (continued) Glipizide May increase risk of low blood sugar level. Glyburide May increase risk of low blood sugar level. May affect itraconazole and/or indinavir Reduce dose of indinavir to 600mg 3 times a day when combined with itraconazole 200mg twice daily. Isoniazid May decrease itraconazole Increases itraconazole Dose of itraconazole should not exceed 200mg/ day. Lovastatin Midazolam (oral) decrease itraconazole Itraconazole dose may need to be increased. Nicardipine Increases risk of nicardipine side effects. Check closely. Nifedipine Increases risk of nifedipine side effects. Check closely. Nimodipine Increases risk of nimodipine side effects. Check closely. Nisoldipine Increases risk of nisoldipine side effects. Check closely. Nitrendipine Increases risk of nitrendipine side effects. Check closely. Omeprazole Decreases itraconazole Phenobarbital Decreases itraconazole level and may increase phenobarbital Decreases itraconazole level and may increase phenytoin Pimozide Quinidine Ranitidine Decreases itraconazole D R UG INTERA CTIO NS. AUGUS UGUST 2004. PR O JECT INFORM 13 PROJECT INFORM 205 13TH STREET, SUITE 2001 SAN FRANCISCO ANCISCO, CA 94103-2461 415-558-8669 FAX 415-558-0684 SUPPORT@PR T@PROJECTINFORM.OR OJECTINFORM.ORG WWW.PR.PROJECTINFORM.OR OJECTINFORM.ORG

14 JECT INFORM 4. PR O JECT INFO T 2004. P UGUST 200 NS. AUGUS CTIO NS. A UG INTERA CTI D R UG INTER Itraconazole plus (continued) Should not be used together. May increase rifabutin level and may decrease itraconazole rifampin level and may decrease itraconazole significantly increase itraconazole level in Increases saquinavir However, no Saquinavir (Invirase) Increases saquinavir However, no Simvastatin Sirolimus Increases sirolimus Tacrolimus Increases tacrolimus Tedalafil Increases tedalafil Tedalafil dose should not exceed 10mg in a 72 hour period. Testosterone May decrease testosterone Tolbutamide May increase risk of low blood sugar level. Trazodone Increases trazodone Trazodone doe may need to be reduced. Trimetrexate May affect trimetrexate and/or itraconazole Vardenafil Increases vardenafil If taking 400mg itraconazole per day, dose of vardenafil should not exceed 2.5mg/day. If taking 200mg itraconazole per day, dose of vardenafil should not exceed 5mg/day. Verapamil Increases risk of verapamil side effects. Check closely. Vinblastine Increases vinblastine Check Vincristine Increases vincristine Check for side effects. Itraconazole plus (continued) Warfarin increase prothrombin (coagulation) time and increase anticoagulant effects. Check warfarin dose closely. Kaletra (lopinavir/ritonavir) plus Kaletra is a single pill containing 2 anti-hiv drugs, lopinavir and ritonavir. References below indicate which drug contained in Kaletra is specifically altered in combinations. Amiodarone May increase amiodarone Checking amiodarone level in blood is recommended. Decreases lopinavir level by 15% and increases amprenavir trough level about 2-fold in Amprenavir dose may be reduced to 750mg twice a day or less. However, optimal dose is unclear. Astemizole Atorvastatin Increases active atorvastatin level about 6- fold and atorvastatin metabolite by 2.5 times in blood and May increase risk Atovaquone Decreases atovaquone Atovaquone dose may have to be increased. Bepridil May increase bepridil Checking bepridil level in blood is recommended. Carbamazepine May decrease lopinavir Cisapride Clarithromycin Increases clarithromycin Clarithromycin dose should be decreased for people with kidney dysfunction. Cyclosporine May increase cyclosporine Checking cyclosporine level in blood is recommended. ddi or ddi EC should be taken 1 hour before or 2 hours after taking Kaletra. ddi and ddi EC should be taken on an empty stomach, and Kaletra should be taken with a meal. May increase lopinavir Needs further study. Dexamethasone May decrease lopinavir Dihydroergotamine Disulfiram/metronidazole Should be used together with Kaletra oral solution with caution. Alcohol in Kaletra oral solution may increase risk Kaletra plus (continued) Efavirenz Decreases lopinavir level by about 25% (trough by about 33%). Kaletra dose should be increased to 4 capsules twice a day. Ergonovine Ergotamine Ethinyl estradiol ethinyl estradiol level by 42% in Use another form of contraception. Felodipine increase felodipine Check for side effects. Increases lopinavir Kaletra should be taken with food. Fosamprenavir Significantly decreases fosamprenavir level in Also increases risk Appropriate dose adjustments not yet established. Increases indinavir trough level by about 4 times in Currently under study; however, indinavir dose should be reduced to no more than 600mg twice a day if used together. Increases itraconazole Itraconazole dose should not exceed 200mg/day. Increases ketoconazole level by 3 times in Ketoconazole dose should not exceed 200mg/day. Lidocaine (systemic) May increase lidocaine Checking lidocaine level in blood is recommended. Lovastatin Methadone Decreases methadone level by 53% in Check for methadone withdrawal symptoms and adjust methadone Methylergonovine Midazolam Decreases lopinavir Kaletra dose may need to be increased. Optimal dose is under study. Decreases lopinavir Kaletra dose should be increased to 4 capsules twice a day. Nicardipine increase nicardipine Check TOLL OLL-FREE NATION TIONAL HIV/AIDS TREATMENT TMENT INFORMATION HOTLINE 1-800-822-7422 LOCAL/INTERN CAL/INTERNATION TIONAL 415-558-9051 MONDAY-FRID -FRIDAY 9-5 SATURD TURDAY 10-4 PACIFIC TIME