Clonidine Hcl 100 mcg, Hydrochlorothiazide 20 mg Tablets

Clonidine stimulates alpha-adrenoreceptors in the brain stem. This action results in reduced sympathetic outflow from the central nervous system and in decreases in peripheral resistance, renal vascular resistance, heart rate, and blood pressure.

The pharmacokinetics of clonidine is dose-proportional in the range of 0.1 to 0.6 mg.

Absorption — The absolute bioavailability of clonidine following oral administration is 70% to 80%. The median (range) time to peak plasma concentrations (Tmax) following oral administration of 50 µg/mL QLONILIK solution under fasting condition was 2 hours (0.75 hour to 8 hours).

Effect of food — Food had no effect on plasma exposure of clonidine after administration of QLONILIK.

Distribution — Following intravenous administration, clonidine displays biphasic disposition with a distribution half-life of about 20 minutes. Clonidine crosses the placental barrier.

Elimination — Elimination half-life ranges from 12 to 16 hour.

Metabolism — About 50% of the absorbed dose is metabolized in the liver.

Excretion — Following oral administration, about 40% to 60% of the absorbed dose is recovered in the urine as unchanged drug in 24 hours.

Patients with Renal Impairment — The half-life increases up to 41 hours in patients with severe impairment of renal function. Clonidine is minimally removed during hemodialysis.

The mechanism of the antihypertensive effect of thiazides is unknown. Hydrochlorothiazide does not usually affect normal blood pressure.

Hydrochlorothiazide affects the distal renal tubular mechanism of electrolyte reabsorption. At maximal therapeutic dosage all thiazides are approximately equal in their diuretic efficacy.

Hydrochlorothiazide increases excretion of sodium and chloride in approximately equivalent amounts. Natriuresis may be accompanied by some loss of potassium and bicarbonate.

After oral use diuresis begins within 2 hours, peaks in about 4 hours and lasts about 6 to12 hours.