Saeed Arayne, Najma Sultana, Shahid Qureshi, Sajida Naseem.
Interaction studies of Omeprazole with Mefloquine, Pyrimethamine and Sulfadoxine.
Pak J Pharm Sci Jan ;19(4):314-21.

Mefloquine hydrochloride, pyrimethamine and sulfadoxine as readily tolerated antimalarial drugs that are highly active against both usual and multidrug resistant strains of Plasmodium falciparum. Omeprazole reduce gastric acid secretion, irreversibly by inhibition of H+_K+ ATPase of the apical membrane of the parietal cell. In order to study the drug interactions of the later with antimalarials, in vitro availability of omeprazole has been studied in presence of mefloquine hydrochloride, pyrimethamine and sulfadoxine. The availability of antimalarial drugs was found to be influenced considerably in presence of omeprazole. The effect of dissolution mediums, simulating various body environments with respect to pH and the influence of temperature on these interactions has been examined in order to elucidate the mechanism of these interactions.

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