Pregnancy

Although no formal safety studies have been carried out, animal studies and a review of over 700 human births in which the infant was exposed to nelfinavir (Viracept) in the womb have found no increased risk of birth defects.1 This suggests that pregnant women may take nelfinavir without risking harm to the foetus, although they may experience higher rates of gastrointestinal side-effects and raised blood sugar levels than non-pregnant women.2

However, recent studies have shown that plasma concentrations of nelfinavir are reduced in pregnant women, although levels of the drug's active metabolite M8 may be unaffected.3 4 Plasma concentrations of the drug should be monitored where possible, and pregnant women should consider increasing the dose of nelfinavir to 1500mg twice a day.5 A double dose on the day of delivery may also be necessary to ensure adequate drug levels.4

In looking at the pharmacokinetics of the 625mg nelfinavir formulation, participants in one study received 1250mg twice daily. In exploring the pharmacokinetic data, investigators for the P1026s study concluded that higher doses of nelfinavir might be considered during pregnancy.6

References

  1. Conner SD et al. Risk of birth defects associated with nelfinavir exposure during pregnancy. Tenth Conference on Retroviruses and Opportunistic Infections, Boston, abstract P782, 2003
  2. Timmermans S et al. Nelfinavir and nevirapine side-effects during pregnancy. AIDS 19: 795-799, 2005
  3. van Heeswijk RP et al. The pharmacokinetics of nelfinavir and M8 during pregnancy and post partum. Clin Pharnacol Ther 76: 588-597, 2004
  4. Hirt D et al. Pregnancy-related effects on nelfinavir-M8 pharmacokinetics: a population study with 133 women. Antimicrob Agents Chemother 50: 2079-2086, 2006
  5. Nellen JFJB et al. Nelfinavir plasma concentrations are low during pregnancy. Clin Infect Dis 39: 736-740, 2004
  6. Read JS, Best BM Pharmacokinetics of new 625mg nelfinavir formulation during pregnancy and postpartum. HIV Med 9(10): 875-882, 2008
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