Hydrochlorothiazide
Medication
thiazide diuretic
heart & blood pressure
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Prescribed for excess fluid and raised blood pressure
When to take
HealthHub: a once-a-day dose is taken in the morning
Take with
Water · HealthHub: a second daily dose sits before 4pm
Pros & cons
Pros
- HealthHub: often a single dose each day
- HealthHub: works on the kidneys to shed water and salt
- FDA label: usual bp start is 25 mg once daily
Cons
- HealthHub: more urine, dry mouth, thirst, dehydration
- HealthHub: can lower blood potassium
- HealthHub: sun-sensitive; a rare skin-cancer signal
Sources
- HSA — Listing of Registered Therapeutic Products (data.gov.sg open dataset, 5,511 rows, cached locally at /tmp/hsa_all.json and filtered offline) · read 2026-08-27
what it says
“All 30 hydrochlorothiazide-containing rows carry Forensicclassification 'Prescription Only'; only 3 are single-ingredient — SIN00108P DI-ERTRIDE TABLET 25 mg · SIN03675P APO-HYDROCHLOROTHIAZIDE 50 mg · SIN03676P APO-HYDROCHLOROTHIAZDE 25 mg”
- HealthHub (National Medication Information workgroup, SG) — Hydrochlorothiazide: what is this medication for · read 2026-08-27
what it says
“Hydrochlorothiazide belongs to a class of medications called Diuretics. It works on your kidneys to get rid of extra water and salts in your body. This medication is used to remove excess fluid from your body.”
- HealthHub — Hydrochlorothiazide: how should I take or use this medication · read 2026-08-27
what it says
“If you are taking one dose a day, take it in the morning … take the second dose before 4pm so that you do not need to wake up often at night to pass urine.”
- HealthHub — Hydrochlorothiazide: what precautions should I take · read 2026-08-27
what it says
“You are allergic to any other medications, especially sulfonamide medicines (e.g. Bactrim) … You have any problems with the way your kidneys work … You have gout … You have lupus or history of lupus”
- HealthHub — Hydrochlorothiazide: common side effects · read 2026-08-27
what it says
“Passing urine more often, dry mouth, increased thirst … Too much water loss may result in dehydration … This medication may cause potassium loss … More sensitive to sunlight, skin rash”
- HealthHub — Hydrochlorothiazide: rare but serious side effects · read 2026-08-27
what it says
“Very rarely, this medication may be linked to the increased risk of Non-melanoma skin cancer … taking higher doses of this medication for long periods … is linked to a very small risk”
- US FDA label for Hydrochlorothiazide tablets, Indications and Usage, via openFDA drug/label.json (effective 2023-12-25) · read 2026-08-27
what it says
“indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis … indicated in the management of hypertension either as the sole therapeutic agent or to enhance the effectiveness of other antihypertensive drugs”
- US FDA label for Hydrochlorothiazide tablets, Dosage and Administration, via openFDA drug/label.json (effective 2023-12-25) · read 2026-08-27
what it says
“For Edema - The usual adult dosage is 25 to 100 mg daily as a single or divided dose … For Control Of Hypertension … 25 mg daily … may be increased to 50 mg daily”
- US FDA label for Hydrochlorothiazide tablets, Precautions — Drug Interactions, via openFDA drug/label.json (effective 2023-12-25) · read 2026-08-27
what it says
“Lithium Generally should not be given with diuretics … add a high risk of lithium toxicity … cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption … by up to 85 and 43 percent”
Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.