How To Get Comfortable With Prescription Oral Medications

Transcription

1 How To Get Comfortable With Prescription Oral Medications Jimmy D. Bartlett, O.D., D.Sc., FAAO Professor Emeritus, The University of Alabama at Birmingham American Optometric Association June 24, 2015 Disclosure Statement Alcon Allergan Bausch & Lomb Jobson Medical Publishing Shire Pharmaceuticals United States Pharmacopeia Please silence all mobile devices. How To Get Comfortable Know the disease state you re treating Know the applicable drug(s) not all, just the few you will be using Know your patient and ask the right questions Don t memorize dosages look them up Clinical experience is key 1

2 Clinical Pearls Select your patients carefully Treat according to your comfort level, or just a little beyond As your experience grows, so will your confidence If possible or practical, spend some time in a colleague s office, a referral center, or other clinic where you can gain hands-on experience Review your cases with a trusted colleague, partner, or faculty member Remember that there are many correct ways to treat ocular disease Importance of Patient History Gives clues to drug contraindications! Medical Hepatic Renal GI Allergies Medications, including OTC Drug Interactions Causing Decreased GI Absorption of Tetracyclines Avoid milk, dairy, and antacids Formation of drug-drug complexes (Ca 2+, Mg 2+ ) Tetracyclines milk, dairy, antacids 2

3 ORAL ANTIVIRAL DRUGS 3

4 Ophthalmic Management No therapy may be required Topical steroids for corneal edema and anterior uveitis Oral analgesics Oral Antivirals Acyclovir Should be started within 72 hours of skin lesions, but can be as late as 1 week 800 mg 5 times daily for 7 days 4

5 Acyclovir Formulations 200 mg capsule 400 mg tablet 800 mg tablet 200 mg/5 ml suspension (banana flavor) Benefits of Acyclovir Therapy Dendriform keratopathy Stromal keratitis Anterior uveitis Acute and chronic pain Few side effects 5

6 Valacyclovir (Valtrex) Prodrug of acyclovir Available as 500 mg tablet Dosage is 1000 mg tid x 7 days 6

7 Famciclovir (Famvir) Prodrug of penciclovir Available as 125, 250, 500 mg tablet Dosage is 500 mg tid x 7 days Side Effect(s) of Antivirals Nausea Diarrhea What to Ask Before Prescribing Are you allergic to antiviral medications such as acyclovir ( Zovirax )? Have you been treated before with this medicine and had to stop for any reason? Are you pregnant or nursing? get in the habit of asking this question unless the patient is not a female of childbearing potential 7

8 Don t Forget These Procedures! Slit lamp exam Uveitis? IOP Dilated fundus exam Retinitis? Acyclovir in Active HSV Keratitis Oral acyclovir 400 mg 5 times daily for treatment of HSV epithelial keratitis Does not prevent stromal disease Does not benefit stromal keratitis in patients receiving topical antivirals and steroids Acyclovir in Preventing Recurrent HSV Keratitis Effective preventive dose is 400 mg BID (or Valtrex 500 mg QD) Dendritric (epithelial) Even effective for disciform (stromal) Because of expense, greatest benefit is in suppression of vision-threatening stromal disease 8

9 ORAL ANTIBACTERIAL DRUGS Conditions Requiring Oral Antibacterial Drugs Preseptal cellulitis Internal hordeolum Meibomian gland dysfunction* Chlamydial conjunctivitis Ocular rosacea* Dacryocystitis A Good Place To Start is Preseptal Cellulitis or Internal Hordeolum 9

10 Eyelid Anatomy Etiology Local infection of eyelid or adnexa Eyelid or facial trauma Upper respiratory tract infection 10

11 Be Comfortable With The Diagnosis Differentiate From Orbital Cellulitis Proptosis Visual acuity Pupils Ocular motility Pain and fever Constitutional symptoms Differentiation From Orbital Cellulitis Clinical Finding Preseptal Cellulitis Orbital Cellulitis Proptosis Absent Marked Chemosis Rare Common Vision Normal Often reduced Pupils Normal May be APD Motility Usually normal Restricted Pain on motion Absent Present IOP Normal May be elevated Temperature Usually normal Elevated (>102 ) General Treatment Strategy (Adult) Largely empirical Penicillinase-resistant penicillin or First-generation cephalosporin 11

12 Penicillins Penicillins Resistant to Penicillinase (β Lactamase) Methacillin Oxacillin Cloxacillin Dicloxacillin Nafcillin 12

13 Penicillin-ß Lactamase Inhibitor Combination (Broad Spectrum) Amoxicillin/Clavulanate (Augmentin) Expensive! (875 mg x 20 = $145) Generic is $32-$46 13

14 Augmentin* Formulation Amoxicillin Clavulanic Acid Tablet 250, 500, 875 mg 125 mg Chewable Tablet 200, 250, 400 mg mg Oral Suspension 125, 200, 400 mg per 5 ml mg per 5 ml *All formulations are pregnancy cat. B and probably safe during breastfeeding Augmentin Formulations What To Ask Before Prescribing Are you allergic to penicillin or cephalosporin drugs such as Keflex? True allergy signs and symptoms include: Hives Itching Rash Acute low blood pressure Laryngeal edema/difficult breathing Upset stomach is not an allergic response Are you pregnant or nursing? 14

15 Cephalosporins First-Generation Cephalosporins Name Cephalexin (generic) Keflex Cephradine (generic) Velosef Cefadroxil (generic) Duricef Formulation 250, 500 cap 250, 500 mg, 1 g tab 125, 250 mg/5ml 250, 500 mg cap 125, 250 mg/5ml 250, 500 mg cap 125, 250 mg/5ml Second-Generation Cephalosporins Name Cefaclor (generic) Ceclor, Ceclor CD Cefprozil (Cefzil) Formulation 250, 500 mg cap 375, 500 mg tab 125, 250, 375 mg/5ml 250, 500 mg tab 125, 250 mg/5ml 125, 250, 500 mg tab Cefuroxime (Ceftin) 125, 250 mg/5ml Loracarbef (Lorabid) 200, 400 mg cap/100, 200 mg/5ml 15

16 Ceftin Formulations As You Go From 1 st to 2 nd to 3rd You increase gram-negative coverage You lose gram-positive coverage You increase cost astronomically! So use 1 st generation cephalosporins for adults and children with presumed staph infection Use 2 nd generation for children with URIs Allergic Reactions to β-lactam Antibiotics Prevalence of penicillin allergy is only 2% Avoid penicillin in patients with history of severe PCN allergy Acute low blood pressure Extensive hives, swelling, itching Laryngeal edema Patients with mild PCN reactions can usually be given a cephalosporin 16

17 Macrolides Azithromycin Formulations Formulation Strength Cost Tablet Oral Suspension* 250, 600 mg 100, 200 mg/5ml 2 g/60 ml (single dose) Z-Pak 250 mg tablets (6) $26 Tri-Pak 500 mg tablets (3) $44 *Take at least 1 hr before or 2 hr after meals 17

18 What To Ask Before Prescribing Are you allergic to mycin drugs? Did you have to stop treatment with a mycin drug for any reason? Are you pregnant? Avoid clarithromycin in pregnancy (category C) Azithromycin and erythromycin are cat. B 18

19 Antibiotic Combinations Trimethoprim/Sulfamethoxazole Trimethoprim/Sulfamethoxazole Name Trimethoprim/sulfamethoxazole (generic) Bactrim, Bactrim DS Cotrim, Cotrim DS Septra, Septra DS Formulation 80 mg trim/400 mg sulf 160/800 mg (double strength) 40/200 mg/5ml Same as above Bactrim is a Sulfonamide! 19

20 Sulfonamide ( Sulfa ) Allergy Sulfur is not a sulfonamide Sulfites are not sulfonamides Sulfates are not sulfonamides ACNE ROSACEA AND MEIBOMIAN GLAND DYSFUNCTION (MGD) 20

21 Acne Rosacea Tetracyclines 21

22 Here We Use Tetracyclines As Antiinflammatories, Not Antimicrobials Inhibit lipase activity of normal lid flora Inhibit matrix metalloproteinases (MMPs) and other inflammatory mediators Anticollagenase properties Antilipase Activity and Matrix Metalloproteinase (MMP-9) Inhibition Typical Response To Treatment 22

23 Prescription for Doxycycline Doxycycline 50 mg 06/24/15 # 60 Sig.: Take one PO BID for ocular rosacea 3 Side Effects of Tetracyclines Nausea, diarrhea, pseudomembranous colitis For nausea, administer with food Tooth discoloration, bone deformity Photosensitization Esophagitis (do not take within 1 hr of bedtime) Side Effects of Oral Antibacterials 23

24 Side Effects of Antibacterials Hypersensitivity reactions GI irritant effects Nausea, diarrhea Pseudomembranous colitis Vaginal candidiasis Vaginal Candidiasis Treat with oral fluconazole (Diflucan) 150 mg PO x 1(single oral dose) 1-2 yogurts/day Antifungal creams PRESCRIBING DURING PREGNANCY 24

25 Drug Use During Pregnancy FDA Category Clinical Implication Example A No risk to fetus Levothyroxine, vitamin B 6 No evidence of Azithromycin, erythromycin, B risk dicloxacillin, cephalexin C Risk cannot be ruled out Clarithromycin, ciprofloxacin, methylprednisolone dose pack D Risk to fetus Tetracycline, doxycycline X Definite risk! Misoprostol, isotretinoin PRESCRIBING FOR CHILDREN Pediatric Dosage Calculation* Clark s Rule Pediatric Dose = Adult Dose x or Adult Dose x Weight (kg) 70 Weight (lb) 150 *5 ml = 1 tsp 25

26 Pediatric Dosage Calculation By Age Age Percent of Adult Dose >12 100% % % Pediatric Azithromycin Example For FDA-Approved Dosage 6 year-old female Weighs 40 lb Recent URI Presents with red, swollen, painful RUL Dosage is 10mg/kg x 1d, then 5mg/kg x 4d Pediatric Azithromycin Example Amanda Jane Doe 6 06/24/15 Zithromax 200mg/5 ml Sig.: One tsp PO on first day, then onehalf tsp QD x 4 days for eye infection. Take 1 h ac or 2 h pc 26

27 Reread Your Prescription for Accuracy! 27