Pregnancy

Nevirapine (Viramune) is safe for use in pregnant women.1 2 However, the use of nevirapine in pregnant women poses an elevated risk of liver toxicity, which has been fatal to mothers and foetuses.3 4 There is also evidence that blood levels of nevirapine are reduced in pregnant women, which may increase chances of developing resistance.5

Treatment with nevirapine during labour has also been shown to reduce mother-to-baby transmission of HIV. The advantage of nevirapine is that a single dose could be affordable even in developing countries, where the cost of regular treatment with most anti-HIV drugs makes their use unrealistic. The key study showing nevirapine’s effectiveness in reducing HIV transmission was HIVNET 012, which compared a single dose of nevirapine to a short course of AZT during labour and during the first week of life in over 600 women in Uganda. At birth, the treatments were similarly effective, but after 14 weeks of breastfeeding, the rate of HIV infection was 13% in the nevirapine group and 25% in the AZT group.6

Later studies have demonstrated that single doses of nevirapine during labour, with or without a dose for the infant after birth can further reduce the risk of transmission when added to a course of AZT treatment.7 8 However, maternal exposure to nevirapine compromised subsequent triple therapy including nevirapine, even in women who did not have detectable NNRTI resistance.9 10 11 12 Consequently, in February 2004, the World Health Organization recommended that short-course regimens of nevirapine monotherapy not be used when standard regimens are available. This was due to the risk of nevirapine resistance and because AZT in combination therapy reduced transmission to a greater extent than nevirapine alone.13 This was followed in July 2004 by the South African Medicines Control Council recommending that nevirapine should no longer be used as the sole drug in short course treatment in preventing mother-to-child transmission. Despite this, recent evidence from a small South African study suggests that giving AZT and 3TC to women who have received short-course nevirapine during labour may reduce the risk that they will develop resistance to nevirapine.14

There is also evidence that breast milk may be a reservoir for nevirapine-resistant virus and breastfed infants may be at risk of contracting a nevirapine-resistant form of HIV during the early weeks of life.15 Despite this risk, a recent study has shown that mothers who take nevirapine while breast-feeding produce levels of the drug in the milk high enough to prevent or reduce the risk of mother-to-child transmission in areas where there is no practical alternative to breastfeeding.16

For more information on the use of nevirapine and other anti-HIV drugs to prevent mother-to-child transmission of HIV, see Antiretroviral therapy during pregnancy.

References

  1. Mirochnick M et al. Pharmacokinetics of nevirapine in human immunodeficiency virus type 1-infected pregnant women and their neonates. Pediatric AIDS Clinical Trials Group Protocol 250 Team. J Infect Dis 178: 368-374, 1998
  2. Marazzi MC et al. Safety of nevirapine-containing antiretroviral triple therapy regimens to prevent vertical transmission in an African cohort of HIV-1-infected pregnant women. HIV Med 7: 338-344, 2006
  3. Hitti J et al. Maternal toxicity with continuous nevirapine in pregnancy: results from PACTG 1022. J Acquir Immune Defic Syndr 36: 772-776, 2004
  4. Timmermans S et al. Nelfinavir and nevirapine side-effects during pregnancy. AIDS 19: 795-799, 2005
  5. Haberl A et al. Nevirapine plasma exposure is decreased in pregnant women. 15th International AIDS Conference, Bangkok, abstract TuPeB4644, 2004
  6. Guay LA et al. Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomised trial. Lancet 354: 795-802, 1999
  7. Taha TE et al. Short postexposure prophylaxis in newborn babies to reduce mother-to-child transmission of HIV-1: NVAZ randomised clinical trial. Lancet 362: 1171-1177, 2003
  8. Lallemant M et al. Single-dose perinatal nevirapine plus standard zidovudine to prevent mother-to-child transmission of HIV-1 in Thailand. N Engl J Med 351: 217-228, 2004
  9. Jourdain G et al. Intrapartum exposure to nevirapine and subsequent maternal responses to nevirapine-based antiretroviral therapy. N Engl J Med 351: 229-240, 2004
  10. Jackson JB et al. Identification of the K103N resistance mutation in Ugandan women receiving nevirapine to prevent HIV-1 vertical transmission. AIDS 14: F111-F115, 2000
  11. Eshleman SH et al. Selection and fading of resistance mutations in women and infants receiving nevirapine to prevent HIV-1 vertical transmission (HIVNET 012). AIDS 15: 1951-1957, 2001
  12. Cunningham CK et al. Development of resistance mutations in women receiving standard antiretroviral therapy who received intrapartum nevirapine to prevent perinatal human immunodeficiency virus type 1 transmission: a substudy of pediatric AIDS clinical trials group protocol 316. J Infect Dis 186: 181-188, 2002
  13. Moodley D et al. Evaulation of safety and efficacy of two simple regimens for the prevention of mother to child transmission (MTCT) in HIV infection: nevirapine vs lamivudine and zidovudine used in a randomised clinical trial (the SAINT study). 13th International AIDS Conference, Durban, abstract TuOrB356, 2000
  14. McIntyre J et al. Additon of short-course Combivir to single dose Viramune for prevention of mother-to-child transmission of HIV-1 can significantly decrease the subsequent development of maternal NNRTI-resistant virus. 15th International AIDS Conference, Bangkok, abstract LbOrB09, 2004
  15. Lee E et al. Breast milk shedding of drug-resistant subtype C HIV-1 and among women receiving single-dose nevirapine. Tenth Conference on Retroviruses and Opportunistic Infections, Boston, abstract 96, 2003
  16. Shapiro RL et al. Antiretroviral concentrations in breastfeeding infants of women in Botswana receiving antiretroviral treatment. J Infect Dis 192: 720-727, 2005
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