Oral quinine pharmacokinetics and dietary salt intake

Objectives: The objective was to determine whether or not dietary salt inta ke affects the relative bioavailability of oral quinine. Salt intake has be en shown to alter quinidine bioavailability. Methods: The pharmacokinetic properties of oral quinine sulphate (600 mg sa lt) were investigated in seven healthy Caucasian volunteers, in a randomise d, crossover study, on low- and high-salt diets. Plasma quinine concentrati ons were measured by high-performance liquid chromatography (HPLC) and the 24-h urinary sodium excretion was assayed. Results: Although the 24-h urine sodium excretion was significantly higher when the volunteers were on a high-salt diet, there were no significant dif ferences in quinine AUC0-infinity, t(max), and C-max after the two diets. T he median (range) quinine elimination half-life was significantly shorter a fter a high-salt diet [8.5 (4.3-10.2) h] than after a low-salt diet [10.0 ( 7.6-14.8) h] (P = 0.04). Conclusion: Dietary salt does not affect the relative oral bioavailability of quinine sulphate.