Proguanil Cimetidine

Cimetidine and omeprazole increase the gastric pH, which may lead to an increase in the absorption of proguanil. Cimetidine and omeprazole are also thought to inhibit the metabolism of proguanil, due to their inhibitory effects on cytochrome P450 isoenzyme CYP2C19. 

PROGUANIL H2 RECEPTOR BLOCKERS-CIMETIDINE 1 efficacy of proguanil L absorption and l formation of active metabolite Avoid concomitant use. Clinical significance is not established effectiveness of malarial prophylaxis may be 1... 

CIMETIDINE ANTIMALARIALS OTHER THAN PROGUANIL t efficacy and adverse effects of antimalarials Inhibition of metabolism, some definitely via CYP3A4 Avoid co-administration... 

Cimetidine co-administration increased the C, ax of proguanil, and significantly reduced the C ax and AUC of cycloguanil, presumably by inhibiting the metabolism of proguanil co-administration is probably inadvisable (5). 

Kolawole JA, Mustapha A, Abdul-Aguye I, Ochekpe N, Taylor RB. Effects of cimetidine on the pharmacokinetics of proguanil in healthy subjects and in peptic ulcer patients. J Pharm Biomed Anal 1999 20(5) 737 3. 

CYP2C19 CYP2D6 diazepam, imipramine, 5-mephenytoin, omeprazol, proguanil, propranolol codeine, debrisoquine, dextromethorphan, flecainide, paroxetine, perphenazine, thioridazine carbamazepine, rifampicin cimetidine, felbamate fluoxetine, paroxetine, quinidine... 

There is some evidence that omeprazoie and cimetidine can mod-erateiy reduce the production of the active metaboiite of proguanil, but also some evidence to suggest that this may not be clinically relevant. 

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