Antihypertensive (blood pressure-lowering combination — Angiotensin II Receptor Blocker + Diuretic)
Brand of Losartan Potassium; Hydrochlorothiazide
Last reviewed June 2026
Who is this for?
This is a combination drug containing two medicines — Losartan (which relaxes blood vessels) and Hydrochlorothiazide (a 'water tablet' that helps your body remove excess water and salt through urine). Together, they lower high blood pressure more effectively than either one alone.
Blocks angiotensin II type 1 (AT1) receptors, preventing vasoconstriction and aldosterone release, while hydrochlorothiazide inhibits sodium reabsorption in the distal convoluted tubule, promoting natriuresis and reducing blood volume to synergistically lower blood pressure.
Prescription Required
You need a doctor's prescription to buy this drug.
Explore this drug
The usual dose is one tablet (50 mg Losartan / 12.5 mg Hydrochlorothiazide) taken once daily, with or without food. Swallow with a full glass of water. Try to take it at the same time every day — morning is usually best since the water tablet part may make you urinate more often. Your doctor may increase to 100 mg/25 mg if your blood pressure is not well controlled.
If you miss a dose, take it as soon as you remember. But if it's almost time for your next dose, skip the missed one and continue your normal schedule. Never take two tablets at once to make up for a missed dose.
Always buy from a licensed pharmacy — brands available in Nigeria include Angizaar H, Artazide, CoLosar-Denk, Lorzide, and Presartan H; avoid roadside or unverified sellers as fake versions exist. This is a long-term medication for managing blood pressure — do not stop taking it because you feel fine, as high blood pressure often has no symptoms. Drink enough water, especially during hot weather or if you exercise a lot, because the water tablet component can cause dehydration.
Avoid taking with potassium supplements or potassium-containing salt substitutes, as this can cause dangerously high potassium levels. NSAIDs like ibuprofen (e.g. Brufen, Nurofen) can reduce the blood pressure-lowering effect and harm your kidneys if used regularly — talk to your doctor first. Alcohol can increase dizziness and lightheadedness, so limit or avoid drinking alcohol while on this medicine.
Check your specific combination
Is it safe to take Losartan with your other drugs?
This drug is NOT safe during pregnancy — it can cause serious harm or death to an unborn baby, especially in the second and third trimesters. If you are pregnant, planning to become pregnant, or breastfeeding, do not take this drug and talk to your doctor immediately for a safer alternative.
Store in a cool, dry place away from direct sunlight and heat — Nigerian weather can be hot, so avoid leaving it on windowsills, in cars, or near stoves. Keep the tablets in their original pack and away from moisture. Always keep out of reach of children.
For information only — not medical advice. Always talk to a doctor or pharmacist before changing your medication.
Names this drug is sold under — especially in Nigerian and West African pharmacies
Counterfeit Drug Warning
Fake drugs are a serious problem in Nigeria. Always buy from a registered pharmacy. If the packaging looks different from what is described above, do not use it.
Genuine packaging for CoLosar-Denk 50/12.5 mg Tablets
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NAFDAC Number
B4-5167
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