Hydroflumethiazide Dosage

Usual Adult Dose for Hypertension

Initial dose: 50 mg orally once or twice a day.
Maintenance dose: 25 to 200 mg/day orally.

Usual Adult Dose for Edema

Initial dose: 50 mg orally twice a day.
Maintenance dose: 50 to 100 mg/day orally.

Renal Dose Adjustments

CrCl less than 25 mL/min: Not recommended.

CrCl 25 to 80 mL/min: Initial dose: 25 mg orally once or twice a day.
Maintenance dose: 25 to 200 mg/day orally.

Liver Dose Adjustments

Thiazides should be used with caution in patients with impaired hepatic function or progressive liver disease, since minor alterations of fluid and electrolyte balance may precipitate hepatic coma.

Precautions

Hydroflumethiazide is contraindicated in patients with anuria.

Hydroflumethiazide therapy should be used with caution in severe renal disease. In patients with renal disease, thiazide treatment may precipitate azotemia. Cumulative effects of hydroflumethiazide may develop in patients with impaired renal function. If progressive renal impairment becomes evident, as indicated by rising nonprotein nitrogen or blood urea nitrogen, a careful reappraisal of treatment is necessary with consideration given to withholding or discontinuing diuretic therapy.

Hydroflumethiazide, like other diuretics, should be used with caution in patients with severe liver disease. The possible electrolyte and intravascular fluid shifts associated with hydroflumethiazide-induced diuresis has resulted in hepatic coma and death in some patients with hepatic cirrhosis and ascites.

Sensitivity reactions may be observed in patients with a history of allergy or bronchial asthma.

The possibility of exacerbation or activation of systemic lupus erythematosus has been observed.

All patients receiving thiazide treatment should be observed for clinical signs of fluid or electrolyte imbalance, namely, hyponatremia. hypochloremic alkalosis, and hypokalemia. Serum and urine electrolyte determinations are particularly important when the individual is vomiting excessively or receiving parenteral fluids. Warning signs, irrespective of cause, include dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting.

Hypokalemia may be observed with thiazides as with any other potent diuretic, especially with brisk diuresis or when severe cirrhosis is present. Interference with adequate oral electrolyte intake will also contribute to hypokalemia.

Any chloride deficit is generally mild and usually does not require specific therapy, except under extraordinary circumstances (as in liver disease or renal disease). Dilutional hyponatremia may be observed in edematous patients in hot weather. Appropriate treatment is water restriction, rather than administration of salt, except in rare instances when the hyponatremia is life-threatening. In actual salt depletion, appropriate replacement is the treatment of choice.

Hyperuricemia may occur or frank gout may be precipitated in certain patients receiving thiazide treatment.

Insulin requirements in diabetic individuals may be increased, decreased, or unchanged. Latent diabetes mellitus may become manifested during thiazide use.

Thiazides may decrease serum protein bound iodine (PBI) levels without signs of thyroid disturbance.

Dialysis

Data not available

Other Comments

The maximum recommended dose is 200 mg per day.

Doses greater than 100 mg should be given as 2 divided doses.

Periodic monitoring of electrolytes is recommended, particularly in elderly patients and in patients receiving a high dose.

See also:

Further information

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