Adefovir is an antiviral medicine. You have been prescribed it for chronic hepatitis B infection.
The usual dose is one 10 mg tablet daily. You can take your doses either with or without food.
It is important to take adefovir regularly every day, preferably at the same time each day.
|Type of medicine||An antiviral medicine|
|Used for||Chronic hepatitis B infection in adults|
|Also called||Adefovir dipivoxil; the brand name is Hepsera®|
Hepatitis means inflammation of the liver. Some viruses can cause hepatitis. Hepatitis B is a virus which is carried in your bloodstream to your liver, where it can affect and damage your liver. Following infection with hepatitis B, a few people develop a persistent infection called chronic hepatitis B.
People with chronic hepatitis B usually need treatment to stop or to reduce the activity of the virus. This limits damage to the liver, which is a complication of the infection. One of the types of treatment currently given is an antiviral medicine. Antiviral medicines like adefovir work by stopping the hepatitis B virus from multiplying (replicating); this reduces the amount of the virus in your body.
A doctor who is a liver specialist will usually start the treatment for you. Treatment for chronic hepatitis B usually continues for several years, but can be lifelong. It can include more than one antiviral medicine.
Before taking adefovir
Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking adefovir it is important that your doctor knows:
- If you are pregnant, trying for a baby, or breastfeeding.
- If you have a problem with the way your kidneys work.
- If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine.
How to take adefovir
- Before you start the treatment, read the manufacturer's printed information leaflet from inside your pack. It will give you more information about adefovir, and it will also provide you with a full list of the side-effects which you could experience from taking it.
- Take adefovir exactly as your doctor tells you to. The usual dose is one 10 mg tablet daily. You can take the tablet either with or without food.
- Try to take your doses at the same time of day each day, as this will help you to remember to take adefovir regularly.
- If you are ever sick within one hour of taking a tablet, you should take a second tablet. This is because your body will not have absorbed a sufficient amount of the medicine. If, however, you are sick and it is more than one hour after taking a tablet, you do not need to take a second dose, as your body will have already absorbed the full dose.
- If you forget to take a dose at your usual time, take it as soon as you remember. However, if you do not remember until the following day, leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- Keep your regular appointments with your doctor. This is so that your progress can be monitored. You will need to have some blood tests from time to time.
- It is important that you continue to take adefovir regularly. Treatment for hepatitis B can be long-term. Continue to take the tablets, even if you feel well. This is to keep your liver healthy.
- Treatment with adefovir does not stop you from passing the infection on to others through sexual contact, sharing needles to inject drugs, or from mother to baby. A vaccine is available which protects against hepatitis B and can be offered to your sexual and household contacts who are at risk of being infected. Do not have sex with anyone (especially any sex without using a condom) until they have been fully immunised and have had their blood checked to see that the immunisation has worked.
- Most people with chronic hepatitis B will be advised to eat a normal healthy balanced diet. However, it is likely you will be advised not to drink alcohol. Alcohol will increase the risk and speed of you developing liver damage.
- Medicines similar to adefovir have been associated with a serious side-effect in a few people. This is known as lactic acidosis. It is a problem where there is too much lactic acid in the blood. The symptoms associated with it are listed in the next section 'Can adefovir cause problems?'. Although this has occurred in only a very few people, you must let your doctor know straightaway if you develop the symptoms listed below.
- You must avoid getting pregnant while you are taking adefovir. Make sure you have discussed with your doctor which types of contraception are suitable for you.
- If you buy any medicines, supplements or herbal remedies 'over the counter', check with a pharmacist that they are suitable to take with adefovir and your other medicines.
- If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.
Can adefovir cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the more common ones associated with adefovir. The best place to find a full list of the side-effects which can be associated with your medicine, is from the manufacturer's printed information leaflet supplied with the medicine. Alternatively, you can find an example of a manufacturer's information leaflet in the reference section below. Speak with your doctor or pharmacist if any of the following continue or become troublesome.
|Very common adefovir side-effects (these affect more than 1 in 10 people)||What can I do if I experience this?|
|Feeling tired or weak||Do not drive and do not use tools or machines while affected. If this continues, speak with your doctor|
|Changes to some blood tests||Your doctor will check for these|
|Common adefovir side-effects (these affect less than 1 in 10 people)||What can I do if I experience this?|
|Feeling sick (nausea) or being sick (vomiting), indigestion, wind, tummy (abdominal) pain||Stick to simple meals - avoid fatty or spicy food. If it continues, speak with your doctor|
|Diarrhoea||Drink plenty of water to replace lost fluids|
|Headache||Drink plenty of water and ask a pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know|
|Itchy rash||If troublesome, speak with your doctor|
Your doctor will discuss with you the possibility of this medicine causing a problem called lactic acidosis. Let your doctor know straightaway if you develop the following symptoms:
- Feeling sick (nausea) or being sick (vomiting), tummy pain, loss of appetite, loss of weight, feeling weak or dizzy, and fast or gasping breathing.
If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for further advice.
How to store adefovir
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
Further reading and references
Manufacturer's PIL, Hepsera® 10 mg tablets; Gilead Sciences Ltd, The electronic Medicines Compendium. Dated July 2019.
British National Formulary, 78th Edition (Sep 2019); British Medical Association and Royal Pharmaceutical Society of Great Britain, London.