Fosamprenavir slows the progress of HIV infection.

It is one of a number of medicines that you will need to take regularly.

Fosamprenavir has been associated with some side-effects. Your doctor will discuss these with you before you start treatment.

About fosamprenavir

Type of medicine A protease inhibitor (PI) antiretroviral medicine
Used for Human immunodeficiency virus (HIV) infection in adults and children over 6 years of age
Also called Telzir®
Available as Tablets and oral liquid medicine

Fosamprenavir is an antiretroviral medicine. It is used for human immunodeficiency virus (HIV) infection. It slows the progress of HIV infection, but it is not a cure. HIV destroys cells in the body, called CD4 T cells. These cells are a type of white blood cell and are important because they are involved in protecting your body from infection. If left untreated, the HIV infection weakens your immune system so that your body cannot defend itself against bacteria, viruses and other germs.

Fosamprenavir belongs to a group of antiretroviral medicines known as protease inhibitors (PIs). It is given alongside a number of other antiretroviral medicines, as part of a combination therapy. Taking three or more antiretroviral medicines at the same time is more effective than taking one alone. Taking a combination of different medicines also reduces the risk that the virus will become resistant to any individual medicine.

Fosamprenavir slows down the progress of HIV infection by reducing the amount of virus in your body. This helps improve your immune system and reduces the risk of you developing the complications associated with HIV infection. It will be prescribed for you by a doctor who is a specialist.

Before taking fosamprenavir

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking fosamprenavir it is important that your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have sugar diabetes.
  • If you have hepatitis (liver inflammation), or any other liver problem.
  • If you have haemophilia (an inherited bleeding disorder), or porphyria (a rare inherited blood disorder).
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine. This is particularly important if you know you are allergic to an antibacterial medicine known as a sulfonamide.

How to take fosamprenavir

  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The leaflet will give you more information about fosamprenavir and a full list of side-effects which you may experience from taking it.
  • Take fosamprenavir exactly as your doctor has told you to. It is usual to take two doses each day at the same time as a medicine called ritonavir - take the doses 12 hours apart. If you (or your child) have been given liquid medicine to take, your doctor will advise you about how much should be taken for each dose. The dose will also be on the label of the pack to remind you.
  • If you are taking fosamprenavir tablets, swallow them with a drink of water. Do not crush or break the tablets. You can take them before or after your meals.
  • If you are an adult taking fosamprenavir liquid medicine, you should take your doses when your stomach is empty - this means an hour before a meal or two hours after food. For children (aged 6-18 years) taking fosamprenavir liquid medicine, they should take their doses with a meal, or just afterwards.
  • Try to take fosamprenavir at the same times each day, as this will help you to remember to take it.
  • If you do forget to take a dose, take it as soon as you remember. If it is nearly time for your next dose when you remember, skip the missed dose and take the next dose when it is due. Do not take two doses together to make up for a forgotten dose.

Instructions for using the dosing syringe for Telzir® Oral Suspension:

  1. Shake the bottle well.
  2. Remove the bottle cap, and push the plastic adaptor into the top of the open bottle.
  3. Insert the syringe into the adapter.
  4. Turn the bottle (with the syringe connected to it) upside down.
  5. Gently pull out the plunger of the syringe so that the medicine fills the syringe to the mark which corresponds to your dose.
  6. Turn the bottle the correct way up again, and remove the syringe from the bottle.
  7. Put the tip of the syringe into your mouth, and gently push the plunger so that the medicine is released into your mouth.
  8. Repeat steps 3-7 if you have been told to use more than one syringeful.
  9. Remove the adaptor from the bottle and replace the bottle cap. Wash the syringe and adaptor with water after each use.

Getting the most from your treatment

  • Keep your regular appointments with your doctor so that your progress can be monitored. You may need to have regular blood tests while you are taking this medicine.
  • It is important that you continue to take fosamprenavir and your other antiretroviral treatment regularly. This will help to prevent the HIV from becoming resistant to the medicines you are taking. Even if you miss only a small number of doses, the virus can become resistant to treatment.
  • If you develop any infection soon after you start this treatment, let your doctor know. As a result of taking fosamprenavir, your immune system may start fighting an infection which was present before you started the treatment, but which you may not have been aware of.
  • Follow carefully any advice your doctor gives to you about making some lifestyle changes to reduce any risk of damage to your heart and blood vessels. These may include stopping smoking, eating healthily and taking regular exercise.
  • Although treatment with antiretroviral medicines may reduce the risk of your passing HIV to others through sexual contact, it does not stop it. It is important that you use condoms.
  • It is not uncommon for people with HIV to feel low or even depressed, especially soon after the diagnosis has been made. If you have any feelings of depression then you should speak with your doctor.
  • Some people who have taken antiretroviral medicines (particularly over a long time) have developed a condition called osteonecrosis. This is where some bone tissue dies because there is a reduced blood supply to it. It can cause joint aches and pains, and lead to difficulties in movement. If you notice any of these symptoms, speak with your doctor.
  • If you buy any medicines, check with a pharmacist that they are suitable to take with fosamprenavir and your other medicines. This is because some remedies interfere with fosamprenavir and stop it from working properly. In particular, do not take St John's wort.
  • If you have diabetes you may need to check your blood glucose more frequently, as this medicine may affect the levels of sugar in your blood. Your doctor will advise you about this.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.
  • Treatment for HIV is usually lifelong. Continue to take fosamprenavir unless you are advised otherwise, even if you feel well. This is to keep your immune system healthy.

Can fosamprenavir cause problems?

Along with their useful effects, all medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common fosamprenavir side-effects - these affect around 1 in 10 people who take this medicine
What can I do if I experience this?
Diarrhoea Drink plenty of water to replace lost fluids
Feeling or being sick, abdominal pain Stick to simple meals - avoid rich or spicy food. If it continues, speak with your doctor
Headache Ask your doctor to recommend a suitable painkiller
Feeling tired or dizzy Do not drive or use tools or machines until you feel better. If this continues, speak with your doctor
Tingling feelings in your mouth Speak with your doctor about this
Itchy skin rash Speak with your doctor about this
Changes to some blood tests Your doctor will check you for this

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store fosamprenavir

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Once a bottle of Telzir® Oral Suspension has been opened it will keep for 28 days - after this time, make sure you have a fresh supply.