BMA Concise Guide to Medicine & Drugs

Zidovudine/Lamivudine

Brand name [zidovudine] Retrovir; [lamivudine] Epivir, Zeffix

Used in the following combined preparations Combivir, Trizivir

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Drug group Drug for HIV and immune deficiency

Overdose danger rating Medium

Dependence rating Low

Prescription needed Yes

Available as generic Yes (zidovudine); No (lamivudine)

GENERAL INFORMATION

Zidovudine and lamivudine belong to the same class of drugs – nucleoside analogues – and are used in the treatment of HIV infection. The two drugs can be prescribed separately or combined in one tablet, which is usually prescribed with another class of drug (either a non-nucleoside reverse transcriptase inhibitor or a protease inhibitor) to treat HIV. This combination of three drugs is more effective at treating HIV than either a single or double regime of drugs.

Although not a cure for HIV, combination antiretroviral therapy (known as highly active antiretroviral therapy, or HAART) slows down production of the virus and, therefore, reduces the viral load and consequent damage done to the immune system. The drugs need to be taken regularly and on a long-term basis to remain effective.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, liquid, injection (zidovudine).

Frequency and timing of doses 1–2 x daily.

Adult dosage range One tablet; 15–30ml liquid; dosage for injection calculated according to body weight.

Onset of effect 1 hour.

Duration of action 12–24 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. If your next dose is due within 2 hours, take a single dose now and skip the next. It is very important not to miss doses on a regular basis as this can lead to the development of drug-resistant HIV.

Stopping the drug Do not stop taking the drug without consulting your doctor.

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.

POSSIBLE ADVERSE EFFECTS

The most common adverse effects of zidovudine and lamivudine are nausea, vomiting, and diarrhoea; fatigue is also common. Discuss with your doctor if these are severe or if significant skin discoloration occurs. If you develop severe abdominal pain, you should contact your doctor immediately. Long-term use of zidovudine and lamivudine may also cause other adverse effects (see Prolonged use).

INTERACTIONS

General note A wide range of drugs may interact with zidovudine and lamivudine causing either an increase in adverse effects or a reduction in the effect of the antiretroviral drugs. Check with your doctor or pharmacist before taking any new drugs, including those from the dentist and supermarket, and herbal medicines.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have liver or kidney problems.

· You have other infections, such as hepatitis B or C.

· You are taking other medicines.

Pregnancy Safety in pregnancy not established. If you are pregnant or planning pregnancy, discuss with your doctor.

Breast-feeding Safety in breast-feeding not established. Breast-feeding is not recommended by HIV-positive mothers as the virus may be passed to the baby.

Infants and children Reduced dose necessary under 12 years.

Over 60 Increased likelihood of adverse effects. Reduced dose may therefore be necessary.

Driving and hazardous work No special problems.

Alcohol No known problems.

PROLONGED USE

There is an increased risk of serious blood disorders, such as anaemia, with long-term use of zidovudine and lamivudine. There may also be a redistribution of fat from the limbs to the abdomen, back, and breasts. This may be accompanied by increases in blood levels of lipids and glucose.

Monitoring Regular blood checks will be carried out to monitor the viral load, blood count, and blood lipid and glucose levels.