B. Incorrect! Peginterferon α-2a is used for the treatment of chronic hepatitis B and may be preferable to interferon- α.

Transcription

1 Pharmacology - Problem Drill 24: Antibiotics, Antifungal and Antiviral Drugs Question No. 1 of reduces the replication of influenza A and B viruses by inhibiting viral neuraminidase. Question #01 (A) Oseltamivir (B) Peginterferon α-2a (C) Nystatin (D) Lamivudine (E) Enfuvirtide A. Correct! Oseltamivir reduces the replication of influenza A and B viruses by inhibiting viral neuraminidase. Peginterferon α-2a is used for the treatment of chronic hepatitis B and may be preferable to interferon- α. Nystatin is an antifungal used to treat oral thrush. Lamivudine is used for the initial treatment of chronic hepatitis B. Enfuvirtide inhibits HIV from fusing to the host cell. Oseltamivir and zanamivir reduce the replication of influenza A and B viruses by inhibiting viral neuraminidase. They are most effective for the treatment of influenza if started within a few hours of the onset of symptoms. In otherwise healthy individuals they reduce the duration of the symptoms by about days. The correct answer is (A).

2 Question No. 2 of 10 Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed. 2. inhibits HIV from fusing to the host cell. Question #02 (A) Oseltamivir (B) Enfuvirtide (C) Nevirapine (D) Delavirdine (E) isoniazid Oseltamivir reduces the replication of influenza A and B viruses by inhibiting viral neuraminidase. B. Correct! Enfuvirtide inhibits HIV from fusing to the host cell. Feedback on Each Answer Nevirapine is non-nucleoside reverse transcriptase inhibitors with activity against HIV-1 but not the HIV-2 type. Delavirdine is non-nucleoside reverse transcriptase inhibitors with activity against HIV-1 but not the HIV-2 type. Isoniazid kills actively growing mycobacteria within host cells. Fusion inhibitors such as enfuvirtide inhibit HIV from fusing to the host cell. It is useful in managing infection that has failed to respond to a regimen of other antiretroviral drugs. It should be combined with other antiretroviral drugs. The correct answer is (B).

3 Question No. 3 of is a narrow-spectrum antifungal agent that is fungistatic. Question #03 (A) Zidovudine (AZT) (B) Griseofulvin (C) Valganciclovir (D) Ganciclovir (E) Nystatin Zidovudine (AZT) is an antiviral drug. B. Correct! Griseofulvin is a narrow-spectrum antifungal agent that is fungistatic. Valganciclovir is an ester of ganciclovir which is licensed for the initial and maintenance treatment of CMV retinitis in AIDS patients. Ganciclovir is a synthetic nucleoside analogue that used for life threatening or sight threatening CMV. Nystatin is an antifungal used to treat oral thrush. Griseofulvin is a narrow-spectrum antifungal agent that is fungistatic. It interacts with the microtubules which causes interference with spindle formation in dividing cells and therefore with mitosis. It is given orally and may cause GI upsets, headache and photosensitivity. Allergic reactions may also occur. The correct answer is (B).

4 Question No. 4 of is given iv for systemic infections and orally for GI infections caused by fungal infection. Question #04 (A) Terbinafine (B) Griseofulvin (C) Nystatin (D) Miconazole (E) Ganciclovir Terbinafine is an allylamine that is fungicidal for a wide range of skin pathogens. Griseofulvin is a narrow-spectrum antifungal agent that is fungistatic. Nystatin is an antifungal used to treat oral thrush. D. Correct! Miconazole is given iv for systemic infections and orally for GI infections caused by fungal infection. Ganciclovir is a synthetic nucleoside analogue that used for life threatening or sight threatening CMV. Miconazole is given iv for systemic infections and orally for GI infections. Unwanted effects are infrequent. The correct answer is (D).

5 Question No. 5 of inhibits bacterial protein synthesis by binding to the 30S ribosome causing an alteration in codon: anticodon recognition. Question #05 (A) Rifampicin (B) Isoniazid (C) Aminoglycosides (D) Clindamycin (E) Antifungals Rifampicin is a potent orally active drug which inhibits mycobacterial RNA polymerase. Isoniazid kills actively growing mycobacteria within host cells. The mechanism of action is unknown. C. Correct! Aminoglycosides inhibit bacterial protein synthesis by binding to the 30S ribosome causing an alteration in codon: anticodon recognition. Clindamycin is a lincosamide that is active against Gram-positive cocci. Antifungals work through other mechanisms. Aminoglycosides inhibit bacterial protein synthesis by binding to the 30S ribosome causing an alteration in codon: anticodon recognition. This group of drugs includes gentamicin, streptomycin, amikacin, kanamycin, tobramycin and neomycin. While they are effective against many aerobic Gram-negative and some Gram-positive organisms, resistance to aminoglycosides is becoming a problem. Aminglycosides are associated with serious side effects such as ototoxicity and nephrotoxicity. The correct answer is (C).

6 Question No. 6 of 10 as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed. 6. is a polyene macrolide antibiotic similar to amphotericin and with the same mechanism of action. Question #06 (A) Terbinafine (B) Griseofulvin (C) Nystatin (D) Miconazole (E) Fluconazole Terbinafine is an allylamine that is fungicidal for a wide range of skin pathogens. Griseofulvin is a narrow-spectrum antifungal agent that is fungistatic. C. Correct! Nystatin is a polyene macrolide antibiotic similar to amphotericin and with the same mechanism of action. Miconazole is given iv for systemic infections and orally for GI infections. Fluconazole may be given orally or intravenously. Since it reaches high concentrations in the CSF, it may be useful in fungal meningitis. Nystatin is a polyene macrolide antibiotic similar to amphotericin and with the same mechanism of action. It is used for oral thrush. The correct answer is (C).

7 Question No. 7 of 10 as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed. 7. is effective against several different types of fungi but is toxic and relapse is common. Question #07 (A) Ketoconazole (B) Terbinafine (C) Flucytosine (D) Amphotericin B (E) Zidovudine A. Correct! Ketoconazole is effective against several different types of fungi but is toxic and relapse is common. Terbinafine is an allylamine that is fungicidal for a wide range of skin pathogens. Flucytosine is a synthetic antifungal mainly effective against yeast infections. Amphotericin B binds has preferential binding activity to fungi and protozoa over human cells. Zidovudine (AZT) is an antiviral drug. Ketoconazole is effective against several different types of fungi but is toxic and relapse is common. It is best absorbed from the GI tract in conditions of low ph. Liver toxicity has been reported and may be fatal. Other side effects include the GI disturbances and pruritus. The correct answer is (A).

8 Question No. 8 of is a potent orally active drug which inhibits mycobacterial RNA polymerase. Question #08 (A) Rifampicin (B) Isoniazid (C) Aminoglycosides (D) Clindamycin (E) Griseofulvin A. Correct! Rifampicin is a potent orally active drug which inhibits mycobacterial RNA polymerase. Isoniazid kills actively growing mycobacteria within host cells. Aminoglycosides inhibit bacterial protein synthesis by binding to the 30S ribosome. Clindamycin is a lincosamide that is active against Gram-positive cocci. Griseofulvin is a narrow-spectrum antifungal agent that is fungistatic. Rifampicin is a potent orally active drug which inhibits mycobacterial RNA polymerase. It penetrates the CSF. Unwanted effects are infrequent, but serious liver damage may occur. It induces hepatic drug metabolizing enzymes and resistance can develop rapidly. The correct answer is (A).

9 Question No. 9 of includes erythromycin as well as the newer clarithromycin and azithromycin. Question #09 (A) Penicillins (B) Reverse transcriptase inhibitors (C) Macrolides (D) Protease inhibitors (E) Fusion inhibitors Think of a newer class of antibiotics. Reverse transcriptase inhibitors are used to treat HIV. C. Correct! Macrolides include erythromycin as well as the newer clarithromycin and azithromycin. Protease inhibitors include saquinavir, ritonavir and lopinavir. Fusion inhibitors such as enfuvirtide inhibit HIV from fusing to the host cell. Macrolides include erythromycin as well as the newer clarithromycin and azithromycin. They are bactericidal and bacteriostatic and exert their effect by inhibiting bacterial protein synthesis through an effect on translocation. Their antibacterial spectrum is the same as that for penicillins. The correct answer is (C).

10 Question No. 10 of Which of the following are both bacteriostatic and bacteriocidal? Question #10 (A) Aminoglycosides (B) Tetracyclines (C) Penicillins (D) Cephalosporins (E) Macrolides Aminoglycosides are bacteriocidal, but not bacteriostatic. Tetracyclines are bacteriostatic, but not bacteriocidal. Penicillins are bacteriocidal, but not bacteriostatic. Cephalosporins are bacteriocidal, but not bacteriostatic. E. Correct! Macrolides are both bacteriostatic and bacteriocidal. Macrolides include erythromycin as well as the newer clarithromycin and azithromycin. They are bactericidal and bacteriostatic and exert their effect by inhibiting bacterial protein synthesis through an effect on translocation. Their antibacterial spectrum is the same as that for penicillins. The correct answer is (E).