Side-effects

The commonest side-effects experienced by people taking nevirapine (Viramune) are rash, nausea, fatigue, headache, vomiting, diarrhoea, abdominal pain, and muscle pain.

Approximately 16% of people starting nevirapine (NVP) will get a rash in the form of red blotches, itchy lumps, and/or speckles on the skin. This usually appears after one to four weeks of treatment and goes away after two to four weeks. Thereafter, most people experience very few or no side-effects.

Prophylactic concurrent treatment with antihistamines during the first two weeks of nevirapine therapy has been shown to reduce the risk of rash.1 However, treatment with the corticosteroid prednisolone has no effect on the number of patients experiencing rash, and can increase its severity.2 3

The rash can be treated in many cases with antihistamines. Beginning treatment with nevirapine at the same time as abacavir (Ziagen) is not recommended as both drugs can cause rashes, and it can be difficult to tell which drug is causing the reaction.

Women seem to be at greater risk than men of developing the mild and severe forms of rash associated with nevirapine.4 5 6 7 A small study has also identified a genetic variant in a human leukocyte antigen gene that may increase the risk of hypersensitivity to nevirapine, including rash and liver problems.8 9

Patients experiencing severe rash or a rash accompanied by fever, blistering, sores in the mouth, conjunctivitis, facial swelling, muscle or joint aches, or general malaise should consult a doctor, who may advise them to stop taking nevirapine.

The US FDA in 2008 issued safety labelling revisions for NVP tablets and oral solution following a number of serious hepatic events and skin reactions. Hepatic failure may be linked to a hypersensitivity reaction, resulting in severe rash (~7%), fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, facial edema, renal dysfunction, and only rarely, Stevens-Johnson syndrome or toxic epidermal necrolysis. Most serious adverse events in the US occurred after NVP treatment as part of a post-exposure prophylaxis regimen in healthcare workers.

A two-week induction stage of NVP at 200mg/day (150mg in children) can often reduce the occurrence of rash. If there is rash and no other symptoms, the NVP dose should not be escalated until the rash is resolved. The lead-in time should not exceed four weeks; if rash is still unresolved, an alternative regimen is suggested.

If severe hepatic, skin, or hypersensitivity reactions occur, NVP therapy should not be resumed. There are cases of hepatic injury damage even after NVP discontinuation. 

In addition to rash, liver toxicity can be a problem in patients beginning NVP.10 11 12 13 The greatest risk of liver toxicity occurs in the first six weeks of treatment. Some experts advise doing a liver panel at baseline, at week two when the nevirapine dose is increased, and then two weeks after that. The first 18 weeks on therapy require vigilance, particularly the first six weeks, which is the time of greatest risk.

For this reason, nevirapine should not be included in a post-exposure prophylaxis (PEP) regimen to prevent HIV infection.14 Pregnant women may also be at particular risk of developing liver toxicity when starting NVP treatment.15 16 One sizable US study even found that while pregnancy posed a risk for liver toxicity in women, nevirapine use did not.17

Less than 1% of patients in clinical trials have stopped NVP treatment due to liver toxicity. While elevated liver enzymes are more common in patients with hepatitis co-infection, these patients are not at increased risk of liver toxicity.

If moderate or severe abnormalities in liver enzymes occur, NVP should be interrupted, only to be restarted when liver enzyme levels return to baseline. NVP can start again at an initial dose of 200mg a day and liver enzymes should be closely monitored. The dose should be increased to 400mg a day with caution after extended monitoring.

In early 2004, Boehringer-Ingelheim updated their safety warning based on a retrospective review of safety data. They stated that women with CD4 counts above 250 cells/mm3 were at 12-fold greater risk of NVP-related liver toxicity than men and that women with CD4 cell counts above this level who are new to treatment should start NVP with caution, as should men with CD4 cell counts above 400 cells/mm3. This warning remains in the prescribing information. However, several subsequent studies have reached different conclusions.  One prospective cohort study of women in Zambia, Thailand and Kenya found that abnormal liver function tests at baseline, not CD4 cell counts, best predicted severe liver damage and associated rash in the first 24 weeks after starting antiretroviral therapy including nevirapine.18

European data suggest that it is safe for patients who have experienced good increases in their CD4 cell counts on another antiretroviral regimen to subsequently switch to nevirapine even when the CD4 count is above the level recommended for initiating treatment with the drug.19 20 An Indian study indicates the same may hold true in resource-limited settings.21 Based on these data, the European Medicines Agency has advised that people with HIV who have an undetectable viral load can safely switch to nevirapine at any CD4 cell count.

Symptoms of liver toxicity include nausea, loss of appetite, fatigue, liver tenderness or swelling, malaise, yellowing of the whites of the eyes, dark greenish-brown urine, yellowing of the skin (jaundice), and greyish or white stools.

High-density lipoprotein (HDL or ‘good’) cholesterol may rise in people taking nevirapine and overall, nevirapine appears to have a better lipid profile than efavirenz.22 23 24

References

  1. Anton P et al. Incidence of rash and discontinuation of nevirapine using two different escalating doses. AIDS 13: 524-525, 1999
  2. Montaner J et al. Randomized, controlled study of the effects of a short course of prednisone on the incidence of rash associated with nevirapine in patients infected with HIV-1. J Acquir Immune Defic Syndr 33: 41-46, 2003
  3. Knobel H et al. Failure of a short-term prednisone regimen to prevent nevirapine-associated rash: a double-blind placebo-controlled trial: the GESIDA 09 / 99 study. J Acquir Immune Defic Syndr 28: 14-18, 2001
  4. Antinori A et al. Female sex and the use of anti-allergic agents increase the risk of developing cutaneous rash associated with nevirapine therapy. AIDS 15: 1579-1581, 2001
  5. Bersoff-Matcha SJ et al. Sex differences in nevirapine rash. Clin Infect Dis 32: 124-129, 2001
  6. de Luca A et al. Gender, use of corticosteroids and CD4 counts are predictive factors of nevirapine-associated rash. AIDS 14: S68, 2000
  7. Mazhude C et al. Female sex but not ethnicity is a strong predictor of non-nucleoside reverse transciptase induced rash. AIDS 16: 1566-1568, 2002
  8. Littera R et al. HLA-dependent hypersensitivity to nevirapine in Sardinian HIV patients. AIDS 20: 1621-1626, 2006
  9. Haas DW et al. Pharmacogenetics of nevirapine-associated hepatotoxicity: an adult AIDS clinical trial group collaboration. Clin Infect Dis 43: 783-786, 2006
  10. de Maat M et al. Hepatotoxicity following nevirapine-containing regimens in HIV-1-infected individuals. Pharmacol Res 46: 295-300, 2002
  11. de Maat MMR et al. Case series of acute hepatitis in a non-selected group of HIV-infected patients on nevirapine-containing antiretroviral treatment. AIDS 17: 2209-2214, 2003
  12. González de Requena D et al. Liver toxicity caused by nevirapine. AIDS 16: 290-291, 2002
  13. Martinez E et al. Hepatotoxicity in HIV-1-infected patients receiving nevirapine-containing antiretroviral therapy. AIDS 15: 1261-1268, 2001
  14. Patel SM et al. Serious adverse cutaneous and hepatic toxicities associated with nevirapine use by non-HIV-infected individuals. J Acquir Immune Defic Syndr 35: 120-125, 2004
  15. Hitti J et al. Maternal toxicity with continuous nevirapine in pregnancy: results from PACTG 1022. J Acquir Immune Defic Syndr 36: 772-776, 2004
  16. Lyons F et al. Nevirapine tolerability in HIV infected women in pregnancy - a word of caution. Second International AIDS Society Conference on HIV Pathogenesis and Treatment, Paris, abstract LB27, 2003
  17. Ouyang DW et al. Increased risk of hepatotoxicity in HIV-infected pregnant women receiving antiretroviral therapy independent of nevirapine exposure. AIDS 23: 2425-30, 2009
  18. Peters PJ et al. Nevirapine-associated hepatotoxicity was not predicted by CD4 count ≥250 cells/µL among women in Zambia, Thailand and Kenya. HIV Medicine. doi:10.1111/j.1468-1293.2010.00873.x, 2010
  19. De Lazzari E et al. Risk of hepatotoxicity in virologically suppressed HIV patients switching to nevirapine according to gender and CD4 count. 46th ICAAC, San Francisco, abstract H-1064, 2006
  20. Wolf E et al. No increased risk for females or high CD4 count in a single-centre HIV cohort. 46th ICAAC, San Francisco, abstract H-1063, 2006
  21. Kumarasamy N et al. Safety of switching to nevirapine-based highly active antiretroviral therapy at elevated CD4 cell counts in a resource-constrained setting. J Acquir Immune Defic Syndr 45: 598 – 600, 2007
  22. van der Valk M et al. Nevirapine containing potent antiretroviral therapy results in an anti-atherogenic plasma lipid profile: results from the Atlantic Trial. Eighth Conference on Retroviruses and Opportunistic Infections, Chicago, abstract 654b, 2001
  23. van Leth F et al. Comparison of first-line antiretroviral therapy with regimens including nevirapine, efavirenz, or both drugs, plus stavudine and lamivudine: a randomised open-label trial, the 2NN Study. Lancet 363: 1253-1263, 2004
  24. Van Leth F et al. Nevirapine and efavirenz elicit different changes in lipid profiles in antiretroviral-therapy-naïve patients infected with HIV-1. PLoS Med 1: e19, 2004
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.