Full Prescribing Info
Dosage/Direction for Use

Adult: Initially, 1.25 mg daily, adjusted after 3-4 wk according to response. Usual dose: 2.5-5 mg daily, either alone or with other antihypertensives. Maintenance dose: 5 mg on alternate days. Formulations with enhanced bioavailability: 0.5-1 mg daily.
Elderly: Initially, 2.5 mg/day or every other day.


Adult: 5-10 mg daily, increased if necessary to 20 mg daily. Max: 80 mg in 24 hr.
Elderly: Initially, 2.5 mg/day or every other day.
Should be taken with food. Take after breakfast.
Anuria; hepatic coma or pre-coma. Pregnancy.
Special Precautions
Pre-diabetes or DM; gout; SLE; hepatic and renal impairment; hypercholesterolaemia. Correct electrolyte disturbances prior to therapy. Risk of cross-sensitivity with sulfonamides, sulfonylureas, carbonic anhydrase inhibitors, thiazides and loop diuretics. Lactation.
Adverse Reactions
Chest pain, palpitation, necrotising angiitis, orthostatic hypotension, syncope, venous thrombosis, vertigo, volume depletion; depression, dizziness, chills, drowsiness, fatigue, restlessness, headache, lightheadedness; petechiae, photosensitivity, hypersensitivity reactions; gout attacks, electrolyte disturbances; abdominal bloating, diarrhoea, abdominal pain, anorexia, constipation, epigastric distress, nausea, xerostomia, pancreatitis, vomiting; impotence; aplastic anaemia, thrombocytopenia, haemoconcentration, leukopenia; cholestatic jaundice, hepatitis; joint pain, muscle cramps, weakness, neuropathy, paraesthesia; blurred vision; increased BUN, glucosuria.
Potentially Fatal: Stevens-Johnson syndrome, toxic epidermal necrolysis.
B D if used in gestational HTN.
Symptoms: Orthostatic hypotension, dizziness, drowsiness, syncope, haemoconcentration and haemodynamic changes due to plasma volume depletion. Management: Symptomatic and supportive.
Drug Interactions
Hypotensive and nephrotoxic effects of ACE inhibitors may be enhanced. Absorption may be reduced with bile acid sequestrants. Hyperglycaemic effect may be enhanced with diazoxide. May increase serum concentration and QTc-prolonging effect of dofetilide. May reduce lithium excretion. Hypotensive effect may be increased with alcohol.
Potentially Fatal: Increased risk of nephrotoxicity with ciclosporin. Severe electrolyte disturbances may occur with furosemide.
Food Interaction
Photosensitisation may occur with dong quai, St John's wort. Hypertension may be exacerbated with ephedra, yohimbe, ginseng. Antihypertensive effect may be increased with garlic. Avoid natural licorice.
Metolazone is a thiazide-like diuretic. It inhibits reabsorption of sodium in the distal tubules resulting in increased excretion of sodium and water, as well as potassium and hydrogen ions.
Onset: Approx 60 min.
Duration: ≤24 hr.
Absorption: Incompletely absorbed from the GI tract (oral).
Distribution: Crosses the placenta and enters breast milk. Protein-binding: 95%.
Metabolism: Not metabolised to a substantial extent.
Excretion: Via urine (80-95% unchanged); via bile and some undergo enterohepatic recycling; 6-20 hr (elimination half-life).
CIMS Class
ATC Classification
C03BA08 - metolazone ; Belongs to the class of low-ceiling sulfonamide diuretics.
Disclaimer: This information is independently developed by CIMS based on metolazone from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to CIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, CIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 CIMS. All rights reserved. Powered by
Register or sign in to continue
Asia's one-stop resource for medical news, clinical reference and education
Sign up for free
Already a member? Sign in