triction of venous return by the expanded uterus is properly treated through elevation of the lower extremities and use of support hose; use of diuretics to lower intravascular volume in this case is illogical and unnecessary. there is hypervolemia during normal pregnancy which is harmful to neither the fetus nor the mother (in the absence of cardiovascular disease), but which is associated with edema, including generalized edema in the majority of pregnant women. if this edema produces discomfort, increased recumbency will often provide relief. in rare instances this edema may cause extreme discomfort which is not relieved by rest. in these cases a short course of diuretics may provide relief and may be appropriate.

ts, thiazides may precipitate azotemia.

monitis and pulmonary edema, photosensitivity, fever, urticaria, rash, purpura. metabolic: electrolyte imbalance (see precautions ), hyperglycemia, glycosuria, hyperuricemia. musculoskeletal: muscle spasm. nervous system/psychiatric: vertigo, paresthesia, dizziness, headache, restlessness. renal: renal failure, renal dysfunction, interstitial nephritis (see warnings ). skin: erythema multiforme including stevens-johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis, alopecia. special senses: transient blurred vision, xanthopsia. urogenital: impotence. whenever adverse reactions are moderate or severe, thiazide dosage should be reduced or therapy withdrawn.

failure. peak plasma concentrations are observed within 1 to 5 hours of dosing, and range from 70 to 490 ng/ml following oral doses of 12.5 to 100 mg. plasma concentrations are linearly related to the administered dose. concentrations of hydrochlorothiazide are 1.6 to 1.8 times higher in whole blood than in plasma. binding to serum proteins has been reported to be approximately 40% to 68%. the plasma elimination half-life has been reported to be 6 to 15 hours. hydrochlorothiazide is eliminated primarily by renal pathways. following oral doses of 12.5 to 100 mg, 55% to 77% of the administered dose appears in urine and greater than 95% of the absorbed dose is excreted in urine as unchanged drug. in patients with renal disease, plasma concentrations of hydrochlorothiazide are increased and the elimination half-life is prolonged. when hydrochlorothiazide is administered with food, its bioavailability is reduced by 10%, the maximum plasma concentration is reduced by 20%, and the time to maximum concentration increases from 1.6 to 2.9 hours. pharmacodynamics: acute antihypertensive effects of thiazides are thought to result from a reduction in blood volume and cardiac output, secondary to a natriuretic effect, although a direct vasodilatory mechanism has also been proposed. with chronic administration, plasma volume returns toward normal, but peripheral vascular resistance is decreased. the exact mechanism of the antihypertensive effect of hydrochlorothiazide is not known. thiazides do not affect normal blood pressure. onset of action occurs within 2 hours of dosing, peak effect is observed at about 4 hours, and activity persists for up to 24 hours. clinical studies: in an 87 patient 4-week double-blind, placebo controlled, parallel group trial, patients who received hydrochlorothiazide capsules had reductions in seated systolic and diastolic blood pressure that were significantly greater than those seen in patients who received placebo. in published placebo-controlled trials comparing 12.5 mg of hydrochlorothiazide to 25 mg, the 12.5 mg dose preserved most of the placebo-corrected blood pressure reduction seen with 25 mg.

nation half-life is prolonged. when hydrochlorothiazide is administered with food, its bioavailability is reduced by 10%, the maximum plasma concentration is reduced by 20%, and the time to maximum concentration increases from 1.6 to 2.9 hours.