entecavir at a glance
Medicine class
Nucleoside analogue antiviral
Usual role
Suppresses hepatitis B virus in selected adults, children and adolescents with chronic infection
Food
Usually taken with or without food; an empty stomach is required in some circumstances
Important
Do not stop without specialist advice because hepatitis can flare
What is entecavir used for?
Uses include:
Licensed treatment of chronic hepatitis B in adults with specified evidence of active disease, including those with compensated or decompensated liver disease.
Licensed treatment of specified nucleoside-naive children and adolescents aged 2 to under 18 years with compensated chronic hepatitis B.
Specialist, non-licensed prevention of hepatitis B reactivation in selected people receiving immune-suppressing treatment.
How does entecavir work?
Inside cells, entecavir is converted to an active triphosphate form. This blocks hepatitis B viral polymerase, interfering with viral DNA production and reducing the amount of virus in the body.
entecavir preparations and strengths
Oral solution
Route: Oral
Strengths: 0.05 mg/mL
How to take entecavir
Take entecavir by mouth exactly as prescribed. Follow the specialist’s food instructions because previous lamivudine failure or decompensated liver disease may require administration on an empty stomach.
The oral solution is ready to use; do not dilute it or mix it with another liquid or medicine.
Measure the prescribed amount using the supplied spoon, holding it upright and checking the mark at eye level.
Swallow directly from the spoon, then rinse it with water and leave it to air dry.
entecavir side effects
Common or expected effects
- Headache
- Tiredness
- Dizziness or sleepiness
- Difficulty sleeping
- Nausea or vomiting
- Diarrhoea or indigestion
- Raised liver enzymes on blood tests
- In children and adolescents, reduced neutrophils are reported very commonly
Get urgent medical advice
- Severe allergic reaction, including swelling or breathing difficulty
- Possible lactic acidosis, which may cause abdominal pain, nausea or vomiting
- Severe worsening of hepatitis during treatment or after entecavir is stopped
entecavir in pregnancy
Human pregnancy data are inadequate, so entecavir should be used only when clearly necessary. Discuss pregnancy, plans to conceive and contraception with the hepatitis specialist. Separate measures are needed to reduce hepatitis B transmission to the baby.
entecavir while breastfeeding
It is unknown whether entecavir enters human milk, and risk to the infant cannot be excluded. The selected product information says breastfeeding should be discontinued during treatment; discuss feeding options with the specialist team.
entecavir interactions
Entecavir has relatively few established metabolic interactions, but kidney elimination and HIV treatment status are important.
Medicines that reduce kidney function or compete for renal tubular secretion
They may increase entecavir or co-administered medicine concentrations, requiring closer monitoring of adverse effects and kidney function.
Lamivudine, adefovir or tenofovir disoproxil
No pharmacokinetic interactions were observed, although previous lamivudine resistance remains clinically important.
Medicines metabolised through cytochrome P450 enzymes
Metabolic interactions are unlikely because entecavir does not inhibit, induce or act as a substrate for these enzymes.
Common questions about entecavir
Answers are fully visible for fast scanning and source review.
Will entecavir cure hepatitis B?
It usually suppresses viral replication rather than eliminating hepatitis B. Specialist monitoring remains necessary even when blood results improve.
Can I pass hepatitis B to someone while taking entecavir?
Yes. Entecavir has not been shown to prevent transmission, so precautions involving sex, blood and shared personal items remain important.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.