Repeated Medical PG Question- 104

#PHARMACOLOGY (NEET-PG)

Q- Which of the following antimicrobials should not be given to a chronic asthmatic patient managed on theophylline therapy?

           A. Erythromycin 

           B. Amoxicillin

           C. Cefotaxime

           D. Cotrimoxazole

ANSWER= A. Erythromycin

Explain:- Drugs which inhibit theophylline metabolism and increase its plasma level are Erythromycin, Ciprofloxacin, Cimetidine, Oral contraceptives, Allopurinol. The dose should be reduced to 2/3.

 

Q- Which of the following antihypertensive drug is avoided in patients with high serum uric acid levels?

           A. Hydrochlorothiazide 

           B. Enalapril 

           C. Prazosin 

           D. Atenolol

ANSWER= A. Hydrochlorothiazide
Explain:- Long-term use of higher dose thiazides in hypertension has caused a rise in blood urate levels.

 

A patient on lithium therapy developed hypertension. He was started on Thiazide for hypertension. After a few days, he developed coarse tremors and other symptoms suggestive of lithium toxicity. What is the probable mechanism of interaction? 

A. Thiazide increases the tubular reabsorption of lithium 

B. Thiazide inhibits the metabolism of lithium 

C. Thiazides act as an add on the drug to lithium

D. All of the above

ANSWER= A. Thiazide increases the tubular absorption of lithium
Explain:- Drug Interaction: Diuretics + Lithium = Decreased excretion—rise in Lithium level - toxicity; Diuretics (thiazide, furosemide) by causing Sodium ion loss to promote proximal tubular reabsorption of Sodium ion as well as Lithium ion → plasma levels of lithium rise. Potassium-sparing diuretics cause milder Lithium ion retention. Management: Reduce dose of lithium and monitor level.