Sounds like ' low-SAR-tan'

Easy-to-read medicine information about losartan – what is it, how to take losartan safely and possible side effects.

Type of medicine Also called
  • Belongs to a group of medicines called angiotensin receptor blockers (ARBs)
  • Losartan Actavis®
  • Cozaar®

What is losartan?

  • Losartan is used to lower high blood pressure (hypertension). It works by relaxing the blood vessels and in this way lowers blood pressure. It also protects your kidneys, and is helpful in patients with diabetes or kidney disease.
  • Losartan is also used to treat heart failure.
  • It is available as tablets.


  • The dose of losartan will be different for different people.
  • Your doctor will usually start you on a low dose, and increase the dose depending on how you respond. This allows your body to get used to the medicine and reduces unwanted side effects.
  • Always take your losartan exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much losartan to take, how often to take it, and any special instructions.

How to take losartan

  • Take losartan, once a day, at the same time each day. It is best taken in the morning.
  • You can take losartan with or without food.
  • Limit alcohol intake while you are taking losartan. Alcohol can increase your chance of side effects such as dizziness and light-headedness.
  • If you forget to take your dose, take it as soon as you remember.
  • But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Do not take potassium tablets while you are taking losartan, unless your doctor tells you to.

Possible side effects

Like all medicines, losartan can cause unwanted side effects, although not everyone gets them. Often unwanted side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Dizziness
  • Feeling light headed
  • Feeling faint when you stand up
  • This is quite common when you first start taking losartan and usually goes way with time
  • Be careful when getting up from either lying down or sitting to avoid falls. These effects puts you at risk of falls and injuries, especially if your are elderly
  • Stand up slowly. If you do feel dizzy sit down, or lie down for a few moments
  • Tell your doctor if  this continues
  • Muscle cramps
  • Muscle weakness
  • Changes in your heart beat (either fast, slow or irregular)
  • Tell your doctor
  • Allergic reaction such as skin rash, itching, swelling of the lips, face, and mouth or difficulty breathing such as chest tightness, or wheezing
  • Tell your doctor immediately or ring HealthLine 0800 611 116
  • Signs of problems with your liver such as yellowing of the skin or eyes, dark urine, pain in the abdomen
  • Tell your doctor immediately or ring HealthLine 0800 611 116


  • Losartan may interact with a few medications and herbal supplements so check with your doctor or pharmacist before starting losartan or before starting any new medicines.
  • Also, check with your pharmacist before taking over-the-counter medicines such as:
    • Cold and flu medicines containing phenylephrine (e.g. Sudafed PE)
    • Anti-inflammatories such as diclofenac (e.g. Voltaren Rapid), ibuprofen (e.g. Nurofen), naproxen (e.g. Naprogesic).

Learn more

The following links provide further information on losartan:

Medsafe Consumer Information Sheet: Cozaar

New Zealand Formulary Patient Information: losartan

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr J Bycroft. Health Navigator NZ