Losartan — NZ Medication Guide | KiwiMeds
✅ Reviewed by a Registered Pharmacist NZ | Last updated: May 2026 | This information is for educational purposes only and does not replace advice from your doctor or pharmacist.
What is Losartan?
Losartan is an angiotensin receptor blocker (ARB) — a type of blood pressure medicine. It works similarly to ACE inhibitors but without causing the dry cough that is common with ACE inhibitors like lisinopril and ramipril.
What is it used for?
Losartan is used to treat high blood pressure, heart failure, and to protect the kidneys in people with type 2 diabetes and high blood pressure. It is often prescribed for people who cannot tolerate the cough caused by ACE inhibitors. It is fully funded by Pharmac.
How does it work?
Losartan blocks angiotensin II receptors in blood vessels and the heart. Angiotensin II is a hormone that causes blood vessels to constrict and blood pressure to rise. By blocking its effects, losartan relaxes blood vessels and lowers blood pressure.
How to take it
Losartan is usually taken once daily, with or without food. Take it at the same time each day. Do not stop taking it suddenly — always talk to your doctor before making any changes.
Common side effects
Losartan is generally well tolerated. Common side effects include dizziness (especially when standing up), tiredness, back pain, and upper respiratory tract infections. Raised potassium levels can occur, particularly in people with kidney disease or diabetes.
Serious side effects to watch for
Seek medical attention for: swelling of the face, lips, tongue, or throat (angioedema — less common than with ACE inhibitors but possible), signs of high potassium (muscle weakness, abnormal heartbeat), and kidney problems (decreased urine output, swelling).
Important drug interactions
NSAIDs (ibuprofen, naproxen) can reduce effectiveness and worsen kidney function. Potassium-sparing diuretics, potassium supplements, and salt substitutes increase potassium risk. Do not combine with ACE inhibitors or the drug aliskiren without specialist advice.
Things to avoid
Avoid NSAIDs — use paracetamol for pain relief instead. Avoid potassium supplements and salt substitutes unless advised by your doctor. Avoid in pregnancy. Limit alcohol as it can enhance blood pressure lowering.
NZ-specific information
Losartan is fully funded by Pharmac. Available as Cozaar and generic brands. A major advantage over ACE inhibitors is the absence of cough in most people. If you had to stop lisinopril or ramipril due to cough, losartan is a common alternative.
Frequently asked questions
Is losartan better than lisinopril? Both are effective blood pressure medicines. The main practical difference is that losartan does not cause the cough associated with ACE inhibitors. Does losartan cause dizziness? Dizziness on standing is possible, especially when first starting — rise slowly from sitting or lying positions.
💬 Always talk to your pharmacist or doctor for advice specific to you. This guide is for general information only and does not replace a professional consultation.
Related medications
Related: Lisinopril, Ramipril, Amlodipine.
References & Further Information
The following New Zealand and international resources were used to inform this page: