Combivir (Zidovudine/Lamivudine)

Some people taking COMBIVIR, or other medicines like it (NRTIs), develop a condition called lactic acidosis, together with an enlarged liver.

Lactic acidosis is caused by a build-up of lactic acid in the body. It is rare; if it happens, it usually develops after a few months of treatment. It can be life-threatening, causing failure of internal organs.

Lactic acidosis is more likely to develop in people who have liver disease, especially women.

Signs of lactic acidosis include:

• deep, rapid, difficult breathing

• drowsiness

• numbness or weakness in the limbs

• feeling sick (nausea), being sick (vomiting)

• stomach pain.

During your treatment, your doctor will monitor you for signs of lactic acidosis. If you have any of the symptoms listed above or any other symptoms that worry you:

See your doctor as soon as possible.

If you feel unwell in any other way or have any symptoms that you do not understand, you should contact your doctor immediately.

Listed below are some side effects that have been noted:

Very common side effects

These may affect more than 1 in 10 people:

• headache

• feeling sick (nausea)

Common side effects

These may affect up to 1 in 10 people:

• being sick (vomiting)

• diarrhea

• stomach pains

• feeling dizzy

• tiredness, lack of energy

• fever (high temperature)

• general feeling of being unwell

• muscle pain and discomfort

• joint pain

• skin rash

• hair loss

Common side effects that may show up in blood tests are:

• a low red blood cell count (anaemia) or low white blood cell count (neutropenia or leucopenia)

• an increase in the level of liver enzymes

• an increased amount in the blood of bilirubin (a substance produced in the liver) which may make your skin appear yellow

• increased levels of lactic acid in the blood

Uncommon side effects

These may affect up to 1 in 100 people:

• shortness of breath

• wind/gas (flatulence)

• itching

• muscle weakness

Uncommon side effects that may show up in blood tests are:

• a decrease in the number of cells involved in blood clotting (thrombocytopenia), or in all kinds of blood cells (pancytopenia)

Rare side effects

These may affect up to 1 in 1000 people:

• difficulty in sleeping (insomnia)

• lactic acidosis

• changes in body shape

• liver disorders, such as an enlarged liver or fatty liver

• inflammation of the pancreas (pancreatitis)

• chest pain; disease of the heart muscle (cardiomyopathy)

• fits (convulsions)

• feeling depressed or anxious, not being able to concentrate, feeling drowsy

• indigestion, taste disturbance

• changes in the colour of your nails, your skin, or the skin inside your mouth

• a flu-like feeling—chills and sweating

• loss of appetite

• breakdown of muscle tissue

• passing urine more often

• enlarged breasts in men

• cough

• sweating

• itchy, bumpy rash (hives)

• tingly feelings in the skin (pins and needles)

Rare side effects that may show up in blood tests are:

• increase in an enzyme called amylase

• a failure of the bone marrow to produce new red blood cells (pure red cell aplasia)

Very rare side effects

These may affect up to 1 in 10 000 people:

• Damage to nerves (peripheral neuropathy) which may include the following:

  • sensation of weakness in the limbs

  • numbness

Very rare side effects that may show up in blood tests are:

• a failure of the bone marrow to produce new red or white blood cells (aplastic anaemia)

If you are pregnant, or planning to become pregnant soon, you must inform your doctor before taking any medicine. The safe use of COMBIVIR in pregnancy has not been established. Your doctor will decide whether you should continue to be treated with COMBIVIR if you are pregnant. If you take COMBIVIR while you are pregnant, talk to your doctor about how you can be included in the Antiretroviral Pregnancy Registry.

Babies and infants exposed to Nucleoside Reverse Transcriptase Inhibitors (NRTIs) during pregnancy or labour show minor temporary increases in blood levels of lactate. The clinical importance of these temporary increases is unknown.

These findings do not affect current recommendations to use antiretroviral therapy in pregnant women to prevent transmission of HIV to their babies. There have been very rare reports of disease that affect the neonatal (babies) nervous system such as delayed development and seizures. The long term effects of COMBIVIR are not known.

It is recommended that HIV infected women do not breastfeed their infants under any circumstances in order to avoid transmission of HIV from mother to child. The active substances in COMBIVIR are likely to be found in breast milk.

You are recommended not to breastfeed your baby while taking COMBIVIR.

REMEMBER: This medicine is for you. Never give it to someone else. It may harm them even if their symptoms are the same as yours.

In pediatric patients with a history of prior antiretroviral nucleoside exposure, a history of pancreatitis, or other significant risk factors for the development of pancreatitis, COMBIVIR should be used with caution. Treatment with COMBIVIR should be stopped immediately if clinical signs, symptoms, or laboratory abnormalities suggestive of pancreatitis occur (see Adverse Reactions).

The class of medicines to which COMBIVIR belongs (NRTIs) can cause a condition called lactic acidosis (excess of lactic acid in your blood), together with an enlarged liver. Symptoms of lactic acidosis include feeling of weakness, loss of appetite, sudden unexplained weight loss, upset stomach and difficulty breathing. This rare but serious side effect occurs more often in women. If you have liver disease you may also be more at risk of getting this condition. While you are being treated with COMBIVIR your doctor will monitor you closely for any signs that you may be developing lactic acidosis. See Side Effects and What to Do About Them: for additional information.

If you have hepatitis B infection, you should not stop COMBIVIR without instructions from your doctor, as you may have recurrence of your hepatitis. This may occur due to you suddenly stopping the active substance lamivudine in COMBIVIR.