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What does it do?

Entecavir is used to treat Hepatitis B.

Before you start

  • Tell your doctor if you have kidney problems or HIV.
  • Tell your doctor if you are pregnant or breastfeeding. If you are planning to get pregnant or find that you are, discuss this with your doctor. Use reliable contraception while taking entecavir.

How should you take it?

Take entecavir as directed with a glass of water. It is very important to take entecavir regularly. If you often forget to take entecavir, it may not work as well.
Some people may need to take entecavir on an empty stomach (2 hours before or 2 hours after food). Check with your doctor.

What if you forget a dose?

If it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time.

Can you take other medicines?

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Tiredness or weakness

Dizziness, headache


Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • You will need regular blood tests while taking entecavir to check your viral load and liver.
  • Very rarely, entecavir can cause a serious condition called lactic acidosis. Stop taking entecavir and tell your doctor immediately if you are feeling very unwell or unusually tired, or if your breathing becomes faster than normal.
  • Do not stop taking entecavir without talking to your doctor first.

This leaflet contains important, but not all, information about this medicine.

Prepared by the MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. March 2023

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at Te Whatu Ora – Waitaha. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed