Nevirapine is able to penetrate the brain and spinal fluid, reducing the likelihood of dementia developing, as Tracy Barnes explains
DRUG NAME:
Nevirapine.
DRUG CLASS:
Non-nucleoside reverse transcriptase inhibitors (NNRTIs), Non-nucleoside analogues or "Non-nukes".
BRAND NAME:
Viramune®
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HOW NEVIRAPINE WORKS: Nevirapine belongs to the group of drugs referred to as non-nucleoside reverse transcriptase inhibitors (NNRTIs) or non-nucleoside analogues.
This class of drugs combat viral replication of HIV by disrupting the essential transcription process of HIV genetic material (RNA) into DNA. How non-nucleosides achieve this is poorly understood. Nevirapine is usually taken in combination with at least two other anti-retroviral drugs, predominantly drugs from the nucleoside analogue class of HIV anti-retrovirals.
HISTORY: Nevirapine was formerly known as BIRG 587.
COMBINATION THERAPY: Nevirapine is an established component of combination anti-retroviral therapy for both treatment-na•ve and treatment-experienced patients. Its effectiveness when used in combination with other HIV anti-retrovirals that have not previously been used has been proven.
Nevirapine is most commonly prescribed in regimes that include two nucleoside analogues and is often considered an effective alternative to a protease inhibitor.
Nevirapine also has the ability to penetrate the brain and spinal fluid, reducing the likelihood of dementia developing.
DOSING: Nevirapine is produced both as a tablet and as an oral suspension. Each white, oval shaped tablet contains 200mg of nevirapine anhydrate. The recommended standard regime is one 200mg tablet taken once a day for the first 14 days, following this 14 day lead-in period a second 200mg dose of nevirapine is introduced, this daily total of 400mg nevirapine establishes the final daily dose for the drug.
Nevirapine suspension contains 10mg of nevirapine per ml and is generally used in the treatment of HIV-positive children.
DOSING RESTRICTIONS: There are no dietary restrictions with nevirapine.
Dosing increments are made over a two-week period, to reduce the incidence of side effects.
Nevirapine should be used as part of combination antiretroviral therapy. Herbal preparations containing St. John's Wort should not be used while taking nevirapine as they reduce their anti-retroviral potency.
It is thought that nevirapine may reduce levels of hormonal contraceptives and women taking nevirapine are advised to consider additional or alternative methods of contraception.
SIDE EFFECTS: The most commonly reported side effect of nevirapine is a skin rash. Approximately 16% of those commencing nevirapine treatment experience this side effect. In most cases the rash subsides after two to four weeks of treatment.
Very rarely, people treated with nevirapine develop a severe and life-threatening rash. This more severe rash usually occurs within the first six weeks of treatment; any patient with severe rash symptoms or rash with accompanying symptoms should consult their physician immediately, treatment will normally be permanently discontinued and not re-introduced.
Liver toxicity is also associated with nevirapine. It is more likely to occur during the first eight weeks of therapy with nevirapine. For this reason, physicians normally monitor liver function during the first three months of therapy. Some very rare cases of liver failure have been reported. Patients experiencing symptoms associated with hepatitis e.g. nausea, loss of appetite, fatigue, liver tenderness or swelling, yellowing of the whites of the eyes, jaundice, dark green/brown urine, pale stools; should consult their physician immediately.
If severe hepatitis is confirmed, nevirapine should be permanently discontinued and not re-introduced.
As with most anti-retrovirals common side effects are more likely to occur during the first few weeks after commencing treatment. The most frequently reported side effects of nevirapine are:
Diarrhoea;
Nausea or vomiting;
Fatigue;
Headache;
Rash.
Apart from the rash, most of the above side effects are remedied with dietary change and/or over the counter medications to alleviate symptoms. It is always wise to check with your physician before taking any other medication in case it interferes with the efficacy of your treatment.
PRE-EXISTING CONDITIONS: Nevirapine should never be re-introduced to patients who previously experienced a hypersensitivity reaction or hepatitis because of treatment with the drug.
Nevirapine should never be used in patients with severe liver failure.
Increased incidence of liver toxicity has been associated with patients who have a history of raised ALT or AST levels and/or hepatitis B and hepatitis C.
PAEDIATRIC USE: Nevirapine is suitable for use in children over the age of 2 months. Children below the age of 16 and above 50kg in weight may follow adult dosing schedules.
For children below 50kg and below 16 years of age the oral suspension is recommended, dosed according to body weight. Children aged 2-8 years should receive 4mg nevirapine per kg body weight, once a day for 14 days, after which, if no rash appears, the dose should be increased to 7mg nevirapine per kg body weight to a maximum dose of 400mg per day. Children aged 8-16 years and less than 50kg in weight should receive 4mg per kg body weight once a day for first 14 days, after which, if no rash appears, the dose should be increased to 4mg per kg body weight twice a day to a maximum dose of 400mg per day.
USE DURING PREGNANCY: The use of nevirapine during labour has been established as an effective regime to reduce HIV transmission from mother to child, although the product is not licensed for this use in the UK.
Nevirapine is known to be able to cross the placenta into the unborn child very effectively due to its lipid solubility and low protein binding. One dose of nevirapine during labour provides the baby with a therapeutic dose of nevirapine, protecting the child during delivery where many of mother to child transmissions occur. Combination therapy during labour and short course therapy to the baby are being investigated. Some concerns have been raised about the possibility of drug resistance when using any anti-retroviral in monotherapy, including nevirapine.
NEVIRAPINE-RESISTANT HIV: In order to minimise the risk of drug resistant HIV developing it is very important that nevirapine is used in combination with drugs that have not previously been included in any treatment regimes and are therefore likely to be effective in reducing viral load below detectable levels. If resistance to nevirapine does develop it is highly likely that cross-resistance to any other drugs in this class will occur.
