To retain relative selectivity, it is important to use the lowest effective dose. Hydrochlorothiazide is a benzothiadiazine diuretic. Thiazides affect renal tubular mechanisms of electrolyte reabsorption and increase excretion of sodium and chloride in approximately equivalent amounts.
Natriuresis causes a secondary loss of potassium.
No change is observed in the bioavailability of either agent when given together in a single tablet. Absorption is not affected whether taken with or without food. Dose proportional increases in plasma bisoprolol concentrations are observed between the 2.5 and 5, as well as between the 5 and 10 mg doses. The pharmacokinetic profile of bisoprolol fumarate has been examined following single doses and at steady state. Once-daily dosing with bisoprolol fumarate results in less than twofold intersubject variation in peak plasma concentrations.