Entecavir is used to treat infections caused by viruses such as hepatitis B infection. Find out how to take it safely and possible side effects.
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What is entecavir?
Entecavir is used to treat long-term hepatitis B infection. It is called an antiviral medicine. Entecavir works by stopping the hepatitis B virus from multiplying and in this way reduces the amount of the virus in your body. It lowers the ability of the hepatitis B virus to infect new liver cells and improves the condition of your liver.
Most people who take entecavir achieve viral suppression, which means means the virus has been controlled and is at low (or undetectable) levels in your blood. However the virus is still present and it does not mean you have been cured. It does not prevent the spread of the virus to others through sexual contact or blood or body fluid contamination, such as sharing used needles. Read more about chronic hepatitis B.
In New Zealand entecavir is available as tablets (0.5 mg).
Dose of entecavir
- The usual dose of entecavir is 0.5 mg once a day.
- Some people may need higher doses (1 mg once a day).
- Your doctor will advise you how long to take entecavir for.
- Always take your entecavir exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.
How to take entecavir
- Swallow your entecavir tablet whole with a glass of water.
- Entecavir is best taken on an empty stomach, at least 2 hours before or 2 hours after food.
- Try taking your dose about the same time each day.
- Limit or avoid alcohol while taking entecavir. Alcohol can increase the chances of side effects like dizziness. Also alcohol may worsen liver problems.
- If you forget to take your dose, take it as soon as you remember. But, if it is nearly time for your next dose, take your next dose at the usual time. Do not take double the dose.
- Keep taking your entecavir tablets for the full time it has been prescribed, even if you feel well.
- Blood tests: you will need regular blood tests while taking entecavir to check how well the medicine is working for you.
Precautions – before starting entecavir
- Are you pregnant, planning a pregnancy or breastfeeding?
- Do you have problems with your kidneys?
- Do you have HIV infection?
- Are you taking any other medicines? This includes any medicines you buy without a prescription, such as herbal and complementary medicines.
If so, it’s important that you tell your doctor or pharmacist before you start entecavir. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.
Possible side effects from taking entecavir
Like all medicines, entecavir can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.
Entecavir can very rarely cause a condition called lactic acidosis. You are at highest risk if you have kidney problems. Contact your doctor immediately if you are being sick (vomiting), feel very unwell, have muscle cramps, become unusually tired or feel short of breath and your breathing becomes faster than normal – these are the signs of lactic acidosis.
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Learn more about entecavir
The following links have more information on entecavir.
- Entecavir New Zealand Formulary
- Hepatitis B – treatments now available for primary care BPAC, NZ, 2018