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Common Brand Name: Cozaar

Side Effects & Precautions

Medically reviewed by Jessica Swirble, PharmD
Last updated on March 16, 2024

Drug Information | Side Effects | Use & Dosage | Request a Prescription

What are the side effects of losartan?

The use of losartan has been shown to cause side effects in some patients.

Common mild side effects of losartan use include:

  • Diarrhea
  • Heartburn
  • Muscle weakness
  • Fatigue
  • Joint or muscle pain
  • Dizziness
  • Back pain
  • Upper respiratory infections

More severe side effects include:

  • Swelling
  • Hoarseness
  • Difficulty breathing or swallowing
  • Chest pain
  • Irregular heartbeat
  • Pale skin
  • Unusual bleeding or bruising
  • Dark-colored urine
  • Yellowing of the skin or eyes

Seek medical attention immediately if you experience any severe symptoms while taking losartan. If you experience mild side effects that become severe or do not go away after a few days, speak to a healthcare provider right away.

What should I tell my healthcare provider before using losartan?

Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with losartan. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.

Tell your provider if you are taking these medications or supplements:

  • Other blood pressure medications
  • Potassium supplements or potassium-sparing diuretics
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)

You should also mention medical conditions such as:

  • Kidney disease
  • Liver disease
  • Heart disease
  • Low blood pressure
  • Dehydration

If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using losartan to assess potential risks and benefits.

Are there any other special instructions I should follow?

You should avoid taking salt substitutes containing potassium while taking losartan. Talk to your healthcare provider about the use of this drug with food, beverages, alcohol, and tobacco. Your provider may recommend that you follow a low-sodium diet while taking losartan.

Your healthcare provider will tell you if you should avoid certain foods, beverages, or products while using losartan. It is extremely important to follow their guidance, as certain drugs can interact with other substances in the body---leading to potentially severe reactions. If you have any questions about special instructions you should follow while taking this drug, talk to your healthcare provider before use.

Losartan is usually prescribed along with healthy lifestyle changes like a reduced-calorie diet and increased physical activity to control blood pressure. Follow your healthcare provider’s guidance regarding these habits while taking losartan.

What should I do in case of an overdose?

The symptoms of a losartan overdose include:

  • Irregular heartbeat
  • Dizziness
  • Fainting

If you experience any of these symptoms, call the poison control helpline at 1-800-222-1222. If an individual has collapsed, is having seizures, or is unresponsive, call 9-1-1 immediately.