Pharmacology of Antimicrobials and Cytotoxic drugs
11. Methicillin:
a. T
b. T
c. T
d. T
12. Chloramphenicol:
a. F
b. T: metabolized primarily in liver to chloramphenicol glucuronide.
c. T
d. F: is a broad spectrum antibiotic.
13. Benzylpenicillin:
a. F
b. F
c. F
d. F: minimally metabolized in the liver except for nafcillin.
14. Trimethoprim and sulfamethoxazole:
a. F: marketed in a fixed ration of 1 part TMP to 5 parts SMZ.
b. T: sulfamethoxazole inhibits the synthesis of dihydropteroic acid from PABA while trimethoprim inhibits the synthesis of tetrahydrofolate from dihydrofolate.
c. T
d. T: can cause toxic epidermal necrolysis.
15. Doxycycline:
a. F: 95% of an oral dose is absorbed.
b. F: excreted mainly in bile and faeces and can therefore be used in renal failure.
c. T
d. F: has a long half-life of 16 - 25h.
16. Methotrexate:
a. F: is a structural analogue of tetrahydrofolate but with a much higher affinity for dihydrofolate reductase than folate itself.
b. T: stops the synthesis of the active compound tetrahydrofolate.
c. T: the effects of methotrexate can be reversed by administration of exogenous folate in the form of citrovorum factor, also called folinic acid or leucovorin; this is done when methotrexate must be given in high doses or when accidental overdose occrs; normal cells are 'rescued' whilst tumor cells are still subject to its cytotoxic action.
d. T: used for the maintenance of remission in acute lymphatic leukaemia and for curative therapy of choriocarcinoma, often in combination with other agents.
17. Resistance in cytotoxic drugs is due to:
a. F
b. T
c. F
d. T
18. Erythromycin:
a. F: aminoglycosides is the commonest causative agent.
b. T: used to treat infections of the upper and lower respiratory tracts, soft tissue and skin infections caused by streptococcus.
c. T: commonest side effect of the macrolides.
d. T
19. The following drugs are ototoxic:
a. F
b. T
c. T
d. T
20. Moxalactam:
a. T
b. T: active against Gram-positive cocci and Gram-negative bacilli.
c. T: Cefotaxime and ceftriaxone also enters the CSF; moxalactam has poor activity against Gram-positive cocci and therefore should not be used in the treatment of meningitis due to these organisms.
d. T