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Review of Pharmacology - 9E (2015)

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13. Ans. a. Hypokalemia (Ref: Harrison 18th/351)<br />

Laxative abuse is associated with hypokalemia.<br />

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14. Ans. c. Ceftriaxone (Ref: Harrison 18th/3414)<br />

Erythromycin and sulfamethoxazole are bacteriostatic drugs and cannot be relied upon in serious infections like bacterial<br />

meningitis. Streptomycin is an aminoglycoside effective mainly against gram negative bacteria but is not preferred for<br />

meningitis due to following reasons:<br />

• It cannot kill gram positive organisms responsible for bacterial meningitis like Streptococcus, Staphylococcus<br />

and Listeria, etc.<br />

• To prevent the emergence <strong>of</strong> drug resistance; as it is first line antitubercular drug.<br />

Ceftriaxone is a third generation cephalosporin with broad spectrum antibacterial activity and good CSF penetration. It is<br />

commonly used for empirical treatment <strong>of</strong> acute bacterial meningitis.<br />

15. Ans. b. Beta lactam antibiotics (Ref: Katzung 12th/907-908)<br />

Friends, this question has been unnecessarily made controversial by giving different answers in different books for competitive<br />

exams. Please try to search for the references provided in those books. Now coming to explanation:<br />

• The terms time dependent killing (TDK) and concentration dependent killing (CDK) are applicable only for cidal<br />

drugs. Beta lactams and vancomycin follow TDK whereas aminoglycosides and fluoroquinolones follow CDK.<br />

• Long post-antibiotic effect is shown by most <strong>of</strong> the drugs against gram positive bacteria (including aminoglycosides,<br />

beta lactams, clindamycin and macrolides) but few drugs have long PAE against gram negative bacteria. The table<br />

given in katzung is modified as:<br />

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Now coming to options:<br />

• Clindamycin and erythromycin are static drugs, so can be easily excluded<br />

• Fluoroquinolones follow CDK.<br />

• So, answer is beta lactams as these follows TDK and have long PAE against gram positive cocci.<br />

16. Ans. d. Lamivudine (Ref: Katzung 12th/870)<br />

Lamivudine is nucleoside reverse transcriptase inhibitor (NRTI), not the non-nucleoside reverse transcriptase inhibitor<br />

(NNRTI).<br />

NNRTIs incude:<br />

• Efavirenz<br />

• Nevirapine<br />

• Delavirdine<br />

• Etravirine<br />

• Rilpivirine<br />

17. Ans. c. Ethionamide (Ref: KDT 7th/771)<br />

Ethionamide and PAS are two antitubercular drugs associated with hypothyroidism and goiter.<br />

757<br />

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