- Severe fluid and electrolyte derangements and severe hypokalemia have been reported in patients treated with methyclothiazide
- Treatment with methyclothiazide may precipitate azotemia and cause cumulative drug effects in patients with renal disease or significantly impaired renal function. Caution should be exercised when administered in patients with renal impairment
- Use cautiously in patients with impaired hepatic function or progressive hepatic disease because minor alterations of fluid and electrolyte balance may precipitate hepatic coma
- Sensitivity reactions have been reported in patients with a history of bronchial asthma or allergy
- Worsening or activation of SLE, hyperuricemia, or even frank gout may occur in some patients with the use of methyclothiazide
- Patients should be monitored for clinical signs of electrolyte imbalance including dry mouth, thirst, lethargy, drowsiness, restlessness, hypotension, tachycardia, muscle cramps, oliguria, nausea and vomiting
- Brisk diuresis, presence of severe cirrhosis, concomitant ACTH or corticosteroid administration, inadequate oral electrolyte intake, or prolonged therapy increases the risk of hypokalemia. Hypokalemia may be treated by potassium supplementation or consumption of potassium rich foods
- Dilutional hyponatremia may result during therapy in edematous patients in hot weather; water restriction is the appropriate therapy rather than salt administration, except when hyponatremia is life threatening
- If progressive renal impairment becomes evident, a careful reappraisal of therapy is necessary with consideration given to withholding or discontinuing the drug
- Methyclothiazide may cause activation of latent diabetes mellitus
- Methyclothiazide may decrease urinary excretion of calcium. Marked hypercalcemia may be evidence of hidden hyperparathyroidism. Discontinue therapy before performing tests for parathyroid function
- Increase in total serum cholesterol, total triglyceride levels, and low-density lipoproteins have been reported with methyclothiazide therapy
Cautions: Use cautiously in
- Volume depletion
- Arrhythmias
- Post-sympathectomy patients
- Seizure disorder
- Pregnancy near-term
- Gestational hypertension
- Alcohol intake
- History of pancreatitis
- Elderly patients
Pregnancy Category:B
Breastfeeding: There is no reason to discontinue nursing, if mother needs to take the drug. Large doses may decrease milk production due to intense diuresis. This information is based upon LactMed database (available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 15 June 2011). As per manufacturer's data, due to the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug analyzing the importance of the drug to the mother.

US Trade Name(s)
US Availability
methyclothiazide (generic)

Canadian Trade Name(s)
Canadian Availability

UK Trade Name(s)
UK Availability

Australian Trade Name(s)
Australian Availability
[Outline]




Pricing data from www.DrugStore.com in U.S.A.
- Methyclothiazide 5 MG TABS [Bottle] (MYLAN)
30 mg = $54.99
90 mg = $139.69
Warning: This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit drugstore.com.
Drug Name: Methyclothiazide 5 MG Oral Tablet
Ingredient(s): Methyclothiazide
Imprint: M;29
Color(s): Blue
Shape: Round
Size (mm): 8.00
Score: 2
Inactive Ingredient(s): colloidal silicon dioxide / magnesium stearate / microcrystalline cellulose / pregelatinized starch / sodium lauryl sulfate / sodium starch glycolate / fd&c blue #1
Drug Label Author:
Mylan Pharmaceuticals, Inc.
DEA Schedule:
Non-Scheduled