Omeprazole and dry mouth.

BACKGROUND

Omeprazole causes irreversible inhibition of the hydrogen/potassium adenosine triphosphatase enzyme, leading to a marked reduction in both acid secretion and volume of gastric juice. Reported side-effects include nausea, vomiting, diarrhoea, constipation, and headache. We report the development of dry mouth during omeprazole therapy.

METHODS

We have identified six patients taking omeprazole for more than 6 weeks who complained of a dry mouth. Salivary production was measured as whole salivary flow produced over a 10-min period spat into a collecting vessel and as 5% citric acid-stimulated parotid salivary flow collected with a Lashley cup device placed over the parotid duct. Flow rates were evaluated both during and after cessation of treatment. Saliva produced was then cultured for microbes.

RESULTS

Four of the six had subnormal parotid or whole salivary flow rates on treatment that recovered after stopping treatment. The increase after treatment was marked in four. Significant amounts of Candida albicans grew from the saliva of the three patients with the lowest salivary flows; one saliva also grew Staphylococcus aureus.

CONCLUSIONS

Salivary flow is reduced in some patients treated with omeprazole, returning to normal after cessation of treatment. This reduction may predispose to opportunistic infection, particularly in the edentulous.