Generic Medicine Info
Indications and Dosage
Adult: 25-100 mg daily in 1-2 divided dose. Dose may be administered on alternate days or on 3-5 days each week. Max: 200 mg daily.
Child: 1-2 mg/kg daily as single or in 2 divided doses. <6 months 3 mg/kg daily in 2 divided doses. <2 years Max: 37.5 mg daily. 2-12 years Max: 100 mg daily.
Elderly: >65 years Initially, 12.5 mg daily, titrate as necessary in increments of 12.5 mg.

Adult: Initially, 12.5 mg daily, may be increased up to 50 mg daily as necessary, either alone or with other antihypertensives. Dosage is individualised and may be titrated according to patient condition. Max: 100 mg daily.
Child: 1-2 mg/kg daily as single or in 2 divided doses. <6 months 3 mg/kg daily in 2 divided doses. <2 years Max: 37.5 mg daily. 2-12 years Max: 100 mg daily.
Elderly: >65 years Initially, 12.5 mg daily, titrate as necessary in increments of 12.5 mg.
Renal Impairment
Hypertension: Contraindicated.
Should be taken with food.
Hypersensitivity to sulfonamide-derived drugs. Anuria. Severe renal impairment.
Special Precautions
Patient with electrolyte or fluid disturbances, gout, history or at high risk of skin cancer (e.g. light-coloured-skin, immunosuppression), Addison’s disease, SLE, ascites due to cirrhosis, diabetes, hypercholesterolaemia, bronchial asthma and parathyroid disease. Mild to moderate renal impairment and hepatic impairment. Children and elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Photosensitivity, non-melanoma skin cancer (NMSC) (long-term use), SLE, electrolyte imbalance (e.g. hyponatraemia, hypokalaemia, hypochloremic alkalosis, hypomagnesaemia), hypersensitivity reactions (e.g. anaphylactoid reactions, necrotizing angiitis, respiratory distress, fever, urticaria, rash, purpura), acute transient myopia, acute angle-closure glaucoma.
Blood and lymphatic system disorders: Aplastic anaemia, agranulocytosis, leukopenia, haemolytic anaemia, thrombocytopenia.
Cardiac disorders: Hypotension, orthostatic hypotension.
Eye disorders: Blurred vision (transient), xanthopsia.
Gastrointestinal disorders: Pancreatitis, jaundice, diarrhoea, vomiting, sialadenitis, cramping, constipation, gastric irritation, nausea, anorexia.
General disorders and administration site conditions: Weakness.
Metabolism and nutrition disorders: Hyperglycaemia, glycosuria, hyperuricaemia.
Musculoskeletal and connective tissue disorders: Muscle spasm.
Nervous system disorders: Vertigo, paraesthesia, dizziness, headache, restlessness.
Renal and urinary disorders: Renal failure, renal dysfunction, interstitial nephritis.
Reproductive system and breast disorders: Impotence.
Skin and subcutaneous tissue disorders: Stevens-Johnson syndrome, toxic epidermal necrolysis, alopecia.
Patient Counseling Information
This medicine may cause dizziness, if affected, do not drive or operate machinery. This medicine may cause photosensitivity reactions, avoid exposure to direct sunlight and UV light and apply sunscreen when going outdoors.
Monitoring Parameters
Monitor serum electrolytes (e.g. Na, K), blood pressure, BUN, renal function tests, fluid status and creatinine. Assess skin for photosensitivity and skin cancer.
Symptoms: Electrolyte depletion (e.g. hypokalaemia, hypochloraemia, hyponatremia), extreme diuresis resulting to dehydration. Management: Symptomatic and supportive treatment. May induce emesis or perform gastric lavage. Administration of activated charcoal may be given within 1 hour of ingestion. Correct dehydration, electrolyte imbalance, hepatic coma, and hypotension by established procedures. Give oxygen or artificial respiration for respiratory impairment as needed.
Drug Interactions
Increases toxicity of lithium. Risk of hypokalaemia may be increased when given with drugs that induce torsades de pointes e.g. digitalis glycoside, astemizole, sotalol, terfenadine, pimozide. May enhance orthostatic hypotension with barbiturates and opioids. Additive effect and may enhance first-dose hypotension with α-blockers and ACE inhibitors. Cholestyramine and colestipol resins may reduce absorption of hydrochlorothiazide. Increased K-depleting effect with corticosteroids, ACTH and amphotericin B. May increase response to neuromuscular blocking action of skeletal muscle relaxants (e.g. tubocurarine). May reduce diuretic and antihypertensive effects of diuretics with NSAIDs. May reduce the therapeutic effect of antidiabetics. May decrease excretion thereby increasing toxicity of amines (e.g. amphetamine, quinidine).
Food Interaction
May potentiate orthostatic hypotension with alcohol.
Lab Interference
May interfere with parathyroid function tests. May cause false positive result to aldosterone/renin ratio (ARR).
Description: Hydrochlorothiazide, a thiazide diuretic, inhibits Na reabsorption in the distal tubules resulting to increased excretion of Na, K, Mg hydrogen ions and water.
Onset: Diuresis: Approx 2 hours. Peak effect: Approx 4-6 hours.
Duration: 6-12 hours.
Absorption: Rapidly and well-absorbed from the gastrointestinal tract. Bioavailability: Approx 65-75%. Time to peak plasma concentration: Approx 1-5 hours.
Distribution: Crosses the placenta and enters the breast milk. Volume of distribution: 3.6-7.8 L/kg. Plasma protein binding: Approx 40-68%.
Excretion: Mainly via urine (≥61% as unchanged drug). Elimination half-life: Approx 5-15 hours.
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Hydrochlorothiazide, CID=3639, https://pubchem.ncbi.nlm.nih.gov/compound/Hydrochlorothiazide (accessed on Jan. 20, 2020)

Store between 20-25°C. Protect from light and moisture.
MIMS Class
ATC Classification
C03AA03 - hydrochlorothiazide ; Belongs to the class of low-ceiling thiazide diuretics.
Anon. Hydrochlorothiazide. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 31/07/2019.

Anon. Thiazides General Statement. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 01/08/2019.

Buckingham R (ed). Hydrochlorothiazide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 31/07/2019.

Hydrochlorothiazide 50 mg Tablets (Ascent Pharmahealth Malaysia Sdn Bhd). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my/. Accessed 31/07/2019.

Hydrochlorothiazide Capsule (Sciegen Pharmaceuticals Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 31/07/2019.

Hydrochlorothiazide Tablet (Heritage Pharmaceuticals Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 31/07/2019.

Hydrochlorothiazide Tablets, USP (Mylan Pharmaceuticals Inc). U.S. FDA. https://www.fda.gov/. Accessed 31/07/2019.

Joint Formulary Committee. Hydrochlorothiazide. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 31/07/2019.

Disclaimer: This information is independently developed by MIMS based on Hydrochlorothiazide from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS 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 © 2021 MIMS. All rights reserved. Powered by MIMS.com
  • Hydrochlorothiazide Kausikh
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