Pharmacology of Antimicrobials and Cytotoxic drugs

21.    Aminoglycosides:

a.     should not be mixed with penicillins.

b.     are well absorbed orally.

c.      are ototoxic.

d.      are excreted unchanged in the urine.

22.    Aspirin increases methotrexate toxicity by:

a.      displacement of methotrexate from plasma protein binding sites.

b.      inhibiting renal excretion of methotrexate.

c.      inhibiting hepatic metabolism of methotrexate.

d.      increasing the intestinal absorption of methotrexate.

23.    6-mercaptopurine:

a.      is a toxic antibiotic drug in cancer chemotherapy.

b.      inhibits cell division by binding to micro-tubular proteins.

c.      is used in the therapy of leukaemia.

d.      is converted to an active metabolite.

24.     The alkylating agent:

a.       cyclophosphamide is metabolized by the liver to precursors of active metabolite.

b.      chlorambucil is used for therapy of chronic lymphocytic leukaemia.

c.      carmustine crosses the blood-brain barrier.

d.      mustard (chlorethanamine) is not given orally.

25.    Tetracycline absorption may be reduced by:

a.      aspirin.

b.      aluminium hydroxide.

c.      ferrous sulphate.

d.      calcium carbonate.

26.    Erythromycin stearate:

a.      is susceptible to penicillinase.

b.      is unstable in gastric acid.

c.      is an alternative to tetracycline in mycoplasma infections.

d.      inhibits the formation of bacterial cell wall.

27.    Gentamicin:

a.      is well absorbed orally.

b.      is mainly excreted.

c.      is effective against Pseudomonas aeruginosa.

d.      is nephrotoxic.

28.     Metronidazole:

a.      is useful for the treatment of amoebiasis.

b.      potentiates the anticoagulant effects of racemic warfarin.

c.      sometimes colors the urine brownish-red.

d.      is liable to produce reversible leukopenia.

29.    Bacteria develop resistance to an antimicrobial by:

a.      changing sex.

b.      changing their permeability to the drug.

c.      producing enzymes that inactivates the drug.

d.      transformation.

30.    Ampicillin:

a.      is effective against Haemophilus influenzae.

b.      is resistant to staphylococcal penicillamase.

c.      is stable in stomach acid.

d.      undergoes enterohepatic circulation.

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