How do you take Irbesartan; Hydrochlorothiazide?

Take one tablet once a day, usually in the morning. You can take it with or without food, but try to take it at the same time every day. Swallow the tablet whole with a glass of water. Your doctor will decide whether you need the 150/12.5 mg or 300/12.5 mg strength.

What are the side effects of Irbesartan; Hydrochlorothiazide?

Dizziness or feeling lightheaded (especially when you stand up quickly), feeling tired or weak, headache, nausea, and passing more urine than usual (because of the water tablet component)

Who should not take Irbesartan; Hydrochlorothiazide?

People allergic to Irbesartan, Hydrochlorothiazide, or sulfonamide-related medicines. People with severe kidney or liver problems. People with diabetes or kidney problems who are already taking Aliskiren (another blood pressure drug). Pregnant women or women planning to become pregnant. People with very low potassium or sodium levels.

Prescription

Antihypertensive (combination of Angiotensin II Receptor Blocker and Thiazide Diuretic)

Irbesartan; Hydrochlorothiazide

Q: What is Irbesartan; Hydrochlorothiazide used for?

High blood pressure (hypertension), especially when one medicine alone is not enough to control it

Last reviewed June 2026

Who is this for?

What is this drug?

This is a combination tablet containing two medicines — Irbesartan (which relaxes blood vessels) and Hydrochlorothiazide (a water tablet that helps your body remove extra salt and water through urine). Together, they work to lower high blood pressure more effectively than either one alone.

What is it used for?

High blood pressure (hypertension)especially when one medicine alone is not enough to control it

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High Blood Pressure Heart Failure

How it works

Blocks angiotensin II type 1 (AT1) receptors to prevent vasoconstriction and aldosterone secretion, while inhibiting sodium reabsorption in the distal convoluted tubule to promote diuresis and reduce circulating fluid volume, thereby lowering blood pressure through complementary mechanisms.

Prescription Required

You need a doctor's prescription to buy this drug.

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What to watch out for

Only buy this medicine from a licensed pharmacy — do not buy from roadside sellers or open markets, as fake blood pressure drugs are common in Nigeria. Do not stop taking this medicine on your own even if you feel fine, because high blood pressure often has no symptoms but can cause stroke or heart attack. Drink enough water daily, especially during hot weather, but follow your doctor's advice on fluid intake.

Common Side Effects

Dizziness or feeling lightheaded (especially when you stand up quickly)
feeling tired or weak
headache
nausea
and passing more urine than usual (because of the water tablet component)

Serious Side Effects

Severe dizziness or fainting (could mean your blood pressure has dropped too low)
signs of kidney problems like very little or no urine output
or unusual muscle cramps and weakness with irregular heartbeat (could mean your potassium or sodium levels are dangerously low). Go to the hospital immediately if you notice any of these.

Drug Interactions

Avoid taking this medicine with potassium supplements or potassium-sparing water tablets, as it can cause dangerous changes in your potassium levels. Be careful with painkillers like ibuprofen and diclofenac (very common in Nigeria), as they can reduce the blood pressure-lowering effect and harm your kidneys. Alcohol can make the dizziness and blood pressure drop worse, so limit or avoid it.

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Pregnancy & Breastfeeding Warning

This medicine is NOT safe during pregnancy — it can seriously harm or even kill your unborn baby, especially in the second and third trimesters. It is also not recommended during breastfeeding. Tell your doctor immediately if you become pregnant.

Who Should NOT Take This

People allergic to Irbesartan
Hydrochlorothiazide
or sulfonamide-related medicines. People with severe kidney or liver problems. People with diabetes or kidney problems who are already taking Aliskiren (another blood pressure drug). Pregnant women or women planning to become pregnant. People with very low potassium or sodium levels.

How to Store

Store in a cool, dry place below 30°C — away from direct sunlight and humidity, which is very important in Nigeria's hot weather. Keep it in its original pack and away from children.

For information only — not medical advice. Always talk to a doctor or pharmacist before changing your medication.