Methyclothiazide Dosage
This dosage information may not include all the information needed to use Methyclothiazide safely and effectively. See additional information for Methyclothiazide.
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Usual Adult Dose for:
Additional dosage information:
Usual Adult Dose for Hypertension
2.5 to 5 mg orally once a day.
Usual Adult Dose for Edema
2.5 to 10 mg once a day.
Renal Dose Adjustments
CrCl less than 25 mL/min: Not recommended.
CrCl 25 to 80 mL/min: 2.5 mg orally once a day.
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
Methyclothiazide is contraindicated in patients with anuria.
Methyclothiazide shares with other thiazides the propensity to deplete potassium reserves to an unpredictable level.
There have been isolated cases that certain non-edematous individuals developed severe fluid and electrolyte derangements after only brief exposure to normal doses of thiazide and non-thiazide diuretics.
Thiazides should be used with caution in individuals with renal disease or significant impairment of renal function, since azotemia may be precipitated and cumulative drug effects may occur. If progressive renal impairment becomes evident as indicated by a rising nonprotein nitrogen or blood urea nitrogen, a careful reappraisal of treatment is necessary with consideration given to withholding or discontinuing diuretic therapy.
Methyclothiazide, like other diuretics, should be used with caution in patients with severe liver disease. The possible electrolyte and intravascular fluid shifts associated with thiazide-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.
Exacerbation or activation of systemic lupus erythematosus has been observed.
Hyperuricemia may occur or frank gout may be precipitated in certain patients receiving thiazide treatment.
All patients should be monitored for clinical signs of electrolyte imbalances such as 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, especially with brisk diuresis, when severe cirrhosis is present, during concomitant use of corticosteroids or ACTH, or after prolonged therapy. Interference with adequate oral electrolyte intake will also contribute to hypokalemia. Hypokalemia may be avoided or treated by use of potassium supplements or foods with a high potassium content.
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 therapy 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.
Latent diabetes mellitus may become manifest during thiazide use.
The antihypertensive effects of methyclothiazide may be enhanced in the postsympathectomy patient.
Thiazides may decrease urinary calcium excretion. Thiazides may cause intermittent and slight elevation of serum calcium in the absence of known disorders of calcium metabolism. Marked hypercalcemia may be evidence of hidden hyperparathyroidism. Thiazides should be withdrawn before carrying out tests for parathyroid function.
Thiazides may cause increased concentrations of total serum cholesterol, total triglycerides, and low-density lipoproteins in some individuals. Thiazides should be used with caution in patients with moderate or high cholesterol concentrations and in patients with elevated triglyceride levels.
Dialysis
Data not available
Other Comments
The maximum effective dose for hypertension is 5 mg/day. If after 8 to 12 weeks with the 5 mg/day dosage satisfactory blood pressure control is not attained, another antihypertensive drug should be added.
The maximum effective dose for edema is 10 mg/day.
Periodic monitoring of electrolytes is recommended, particularly in elderly patients and in patients receiving a high dose.
