BMA Concise Guide to Medicine & Drugs

Efavirenz

Brand name Sustiva

Used in the following combined preparation Atripla

QUICK REFERENCE

Drug group Drug for HIV and immune deficiency

Overdose danger rating Medium

Dependence rating Low

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Efavirenz is a non-nucleoside reverse transcriptase inhibitor, which is a type of antiretroviral drug used to treat HIV infection; it is active against HIV type 1 but not against type 2 (which is rare in the UK). Efavirenz is never used alone but is combined with other antiretrovirals, for example two nucleoside analogues, to reduce viral replication. The aim of this treatment is to minimize viral damage to the immune system and to make the emergence of drug resistance less likely. Combination antiretroviral therapy (known as highly active antiretrovial therapy, or HAART) is not a cure for HIV, but if the drugs are taken regularly on a long-term basis, they can reduce the viral load and improve the outlook for the patient. However, the patient remains infectious and will suffer a relapse if treatment is stopped.

INFORMATION FOR USERS

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

How taken/used Tablets, capsules, liquid.

Frequency and timing of doses Once daily, usually at night to minimize adverse effects.

Adult dosage range Up to 600mg, according to body weight.

Onset of effect 1 hour.

Duration of action 24 hours.

Diet advice None.

Storage Keep in the original container in a cool, dry place 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. It may be necessary to withdraw all your drugs gradually, starting with efavirenz.

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

Gastrointestinal upsets, including nausea, vomiting, and diarrhoea, and a rash are the most common adverse effects. The drug can also cause vivid dreams and changes in sleep patterns, but these tend to wear off with time. If any of these symptoms are severe, or if mood changes occur, discuss with your doctor. If a rash develops, contact your doctor without delay.

INTERACTIONS

General note A wide range of drugs may interact with efavirenz, 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 an infection such as hepatitis B or C.

· You are pregnant or planning pregnancy.

· You are taking other medicines.

Pregnancy Should not be used during pregnancy except on strict medical advice. Pregnancy should be avoided when taking efavirenz by using barrier methods of contraception in addition to other methods.

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

Infants and children Not prescribed to children under 3 years. Reduced dose necessary in older children.

Over 60 Reduced dose may be necessary to minimize adverse effects.

Driving and hazardous work Avoid such activities until you have learned how efavirenz affects you because the drug can cause dizziness.

Alcohol No known problems, although some people may find the effects of alcohol are more pronounced while taking efavirenz.

PROLONGED USE

No known problems.

Monitoring Your doctor will take regular blood samples to check the drug’s effects on the viral load. Blood will also be checked for changes in lipid, cholesterol, and sugar levels.