Drugs which increase the level of theophylline include :: (A) Ciprofloxacin, (B) Cimetidine, (C) Allopurinol, (D) All of these
Answer is D. Drugs which inhibit theophylline metabolism and increase its plasma level are:


Erythromycin
Ciprofloxacin
Cimetidine
OCP
Allopurinol


Agents which induce theophylline metabolism and decrease its plasma level are :


Smoking
Phenytoin
Rifampicin
Phenobarbitone