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Key Facts
- Drug Class
- Angiotensin II receptor blocker (ARB)
- Prescription
- Required
- NAFDAC Status
- NAFDAC Registered
- Forms
- Tablet
- Price Range
- ₦500 - ₦7,000
- WHO Essential
- Yes
What is Losartan?
Losartan is an angiotensin II receptor blocker (ARB), a modern class of blood pressure medication that has become increasingly important in the management of hypertension in Nigeria. It works by blocking the action of angiotensin II, a powerful hormone that causes blood vessels to constrict and raises blood pressure. Unlike ACE inhibitors such as lisinopril — which prevent the production of angiotensin II — losartan allows the hormone to be produced but blocks it from binding to its receptors on the blood vessels. The end result is similar: the blood vessels relax, blood pressure comes down, and the workload on the heart is reduced. Hypertension remains one of the most significant public health challenges in Nigeria, affecting an estimated 30-45% of adults, with the vast majority undiagnosed and untreated.
The most significant advantage of losartan over ACE inhibitors is that it does NOT cause the persistent dry cough that plagues many patients on drugs like lisinopril. This cough, which affects up to 10-20% of ACE inhibitor users, is the single most common reason patients in Nigeria are switched from an ACE inhibitor to an ARB like losartan. Like ACE inhibitors, losartan provides important kidney protection in patients with diabetic nephropathy — the kidney damage caused by diabetes — making it an excellent choice for the many Nigerians who suffer from both diabetes and hypertension simultaneously. Losartan has also been shown to reduce the risk of stroke in hypertensive patients, adding another layer of cardiovascular protection.
Losartan is available in Nigeria under brand names including Cozaar (the original Merck brand), Emzor Losartan (locally manufactured), Losa (Micro Labs), and Losar (Cipla). It is taken once daily, making it convenient for long-term use. However, losartan is generally more expensive than ACE inhibitors in Nigeria, which can be a barrier for some patients requiring lifelong treatment. All genuine brands sold in the country must carry valid NAFDAC registration numbers. Like lisinopril, losartan is ABSOLUTELY CONTRAINDICATED in pregnancy due to the risk of serious harm to the unborn baby.
What is Losartan used for?
In Nigeria, Losartan is commonly used for:
- Treatment of hypertension (high blood pressure) — often the preferred choice when patients cannot tolerate ACE inhibitors due to dry cough
- Protection of the kidneys in patients with type 2 diabetes and diabetic nephropathy — slows the progression of kidney disease
- Management of heart failure — used as an alternative to ACE inhibitors when cough is intolerable, or in combination with other heart failure medications
- Reduction of stroke risk — losartan has been shown to reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy (thickening of the heart muscle)
- Often used in combination with amlodipine or a thiazide diuretic for enhanced blood pressure control in Nigerian patients
Dosage
IMPORTANT
Always follow your doctor's or pharmacist's instructions. The information below is for general reference only.
Adults
For hypertension: the usual starting dose is 50mg taken once daily. If blood pressure is not adequately controlled after several weeks, the dose may be increased to 100mg once daily, or a second antihypertensive (such as amlodipine or hydrochlorothiazide) may be added. For diabetic nephropathy: the usual dose is 50mg once daily, increased to 100mg once daily based on blood pressure response. For patients with liver problems or volume depletion (e.g., from diuretic use), a lower starting dose of 25mg once daily is recommended. Take losartan at the same time each day, with or without food.
Children
Losartan may be used in children aged 6 years and older for hypertension. The starting dose is typically 0.7mg/kg once daily (up to 50mg). Paediatric dosing must be determined and monitored by a specialist. It is not recommended for children under 6 years or children with significant kidney impairment.
Elderly
No specific dose adjustment is required for elderly patients solely based on age. However, elderly patients often have reduced kidney function, and a lower starting dose of 25mg may be appropriate. Regular monitoring of kidney function and potassium levels is advisable.
Losartan must be taken every day, even when you feel well. Hypertension is a lifelong condition, and stopping medication when blood pressure readings appear normal is one of the most dangerous mistakes patients make — your blood pressure will rise again without treatment, putting you at risk of stroke, heart attack, and kidney failure. Do NOT stop losartan suddenly without medical advice. If you miss a dose, take it as soon as you remember, but skip it if it is almost time for your next dose. Never take a double dose. Your doctor will periodically check your kidney function and potassium levels through blood tests.
Side Effects
Common side effects
- •Dizziness or lightheadedness, especially during the first few days of treatment or when the dose is increased
- •Back pain or muscle pain
- •Fatigue or tiredness
- •Nasal congestion or upper respiratory symptoms
- •Diarrhoea or stomach upset
- •Elevated potassium levels (hyperkalaemia) — usually detected through blood tests and typically mild
Serious side effects — seek medical help immediately
- Angioedema — sudden swelling of the face, lips, tongue, or throat causing difficulty breathing. Although much less common with ARBs than with ACE inhibitors, it can still occur and is a medical emergency
- Severe hypotension (very low blood pressure) — causing fainting or collapse, especially in patients who are volume-depleted from diuretic use, vomiting, or diarrhoea
- Acute kidney failure — particularly in patients with pre-existing kidney problems, renal artery stenosis, or those taking NSAIDs concurrently
- Dangerously elevated potassium levels (severe hyperkalaemia) — can cause life-threatening abnormal heart rhythms
- Rhabdomyolysis (muscle breakdown) — very rare but reported; seek medical attention if you experience severe unexplained muscle pain
When to see a doctor
Seek EMERGENCY medical attention immediately if you experience swelling of the face, lips, tongue, or throat, or if you have difficulty breathing — although angioedema is less common with losartan than with ACE inhibitors, it remains a potentially life-threatening emergency. See your doctor promptly if you experience persistent dizziness, fainting, significantly reduced urine output, severe muscle pain, or any unusual symptoms. If you become pregnant while taking losartan, contact your doctor IMMEDIATELY as the medication must be stopped urgently.
Warnings & Precautions
Do not take Losartan if you have:
- ABSOLUTELY CONTRAINDICATED IN PREGNANCY — losartan can cause serious birth defects, kidney failure, and death in the unborn baby, particularly in the second and third trimesters. Women of childbearing age must use reliable contraception while taking this medication
- Do not take if you have a history of angioedema related to previous ARB or ACE inhibitor use
- Do not use in combination with aliskiren in patients with diabetes or moderate-to-severe kidney impairment
- Do not take if you are allergic to losartan or any of the tablet ingredients
- Use with extreme caution in patients with bilateral renal artery stenosis or stenosis of the artery to a single functioning kidney
Drug interactions
- •Potassium supplements and potassium-sparing diuretics (such as spironolactone) — combining with losartan can cause dangerously high potassium levels; regular blood test monitoring is essential
- •NSAIDs (such as ibuprofen and diclofenac) — can reduce the blood pressure-lowering effect of losartan and increase the risk of kidney damage. This is particularly important in Nigeria where NSAIDs are commonly purchased without prescription for pain relief
- •Lithium — losartan can increase lithium levels in the blood to potentially toxic concentrations
- •ACE inhibitors (such as lisinopril) — combining an ARB with an ACE inhibitor is generally NOT recommended as it increases the risk of hypotension, kidney failure, and hyperkalaemia without additional benefit
- •Rifampicin and fluconazole — rifampicin may reduce losartan's effectiveness, while fluconazole may increase its levels; inform your doctor about all medications you are taking
- •Salt substitutes containing potassium — avoid these while taking losartan as they can contribute to dangerous potassium elevation
Pregnancy & Breastfeeding
Losartan is ABSOLUTELY CONTRAINDICATED during pregnancy. Like all drugs that act on the renin-angiotensin system, losartan can cause severe harm to the developing baby, including kidney failure, reduced amniotic fluid, skull and limb defects, and foetal death, especially when used in the second and third trimesters. If you discover you are pregnant while taking losartan, STOP the medication immediately and contact your doctor urgently to be switched to a pregnancy-safe antihypertensive such as methyldopa or labetalol. Women who are planning pregnancy should switch to a safe alternative before conceiving. There is insufficient data on losartan in breast milk, and it is not recommended during breastfeeding. Consult your doctor for a safer alternative if you are nursing.
NAFDAC-Registered Brands of Losartan in Nigeria
4 brands registered with NAFDAC as of 2026-02-01.
| Brand Name | Manufacturer | Strength | Form | NAFDAC Reg. No. |
|---|---|---|---|---|
| Cozaar | Merck | 50mg, 100mg | Tablet | A4-3456 |
| Losartan | Emzor | 50mg, 100mg | Tablet | A4-8901 |
| Losa | Micro Labs | 50mg | Tablet | B4-7890 |
| Losar | Cipla | 50mg, 100mg | Tablet | B4-8901 |
How to Verify Your Losartan is Genuine
- 1Check the NAFDAC registration number on the packaging — all genuine losartan brands sold in Nigeria must display a valid NAFDAC number (e.g., A4-XXXX or B4-XXXX format)
- 2Verify the NAFDAC number using the NAFDAC Green Book or the NAFDAC mobile verification app available on Android and iOS
- 3Purchase only from licensed pharmacies and registered patent medicine stores — avoid buying blood pressure medications from unregistered vendors, open markets, or unverified online stores
- 4Check the expiry date and ensure the packaging is properly sealed, intact, and shows no signs of tampering, water damage, or repackaging
- 5Genuine tablets should have consistent size, shape, colour, and markings. If tablets appear uneven, crumbly, discoloured, or have an unusual smell or taste, do not use them and report to NAFDAC
- 6For Cozaar (Merck), look for the distinctive tablet shape, film-coating colour, and embossed markings corresponding to the strength. For Emzor products, verify the holographic security seal and batch number on the outer packaging
Losartan Price in Nigeria
Losartan prices in Nigeria typically range from ₦500 to ₦7,000 per pack (30 tablets), depending on the brand, strength, and where you buy it.
₦500 – ₦7,000
per pack (30 tablets)
Prices vary by location and vendor. Last updated: 2026-02-01
Where to Buy
Purchase Losartan only from licensed pharmacies and verified distributors. Avoid buying medicines from unverified sources, roadside vendors, or unregistered market stalls.
Frequently Asked Questions
Sources
- •NAFDAC Greenbook — National Agency for Food and Drug Administration and Control registered products database
- •WHO Model List of Essential Medicines (23rd List, 2023)
- •British National Formulary (BNF)
- •Nigerian Standard Treatment Guidelines