Administration of praziquantel to pregnant and lactating women

Praziquantel (PZQ) is the safest of all anti-helminthics and now forms the backbone for all national control programs against schistosomiasis (Med. Res. Rev. 3 (1983) 147-200; Bull. WHO 57 (1979) 767-771; Wegner, D.H.G, Therapeutic Drugs (1991), Churchill Livingstone; Adv. Intern. Med. 32 (1987) 193-206; Drugs 42 (1991) 379-405; Pharmac. Ther. 68 (1995) 35-85; Ann. Intern. Med. 110 (1989) 290-296). Despite its lack of known toxicity, the drug was not tested on pregnant or lactating women prior to release. It is currently listed as Pregnancy Category B by the US FDA, which is a drug presumed safe based in animal studies. Unfortunately, this has been interpreted by most national control programs and WHO (1998) to exclude lactating and pregnant women from treatment. In fact, some experts advocate excluding adolescent girls from mass treatment campaigns over this issue. As a result, a large number of women living in endemic countries are currently left untreated or have treatment significantly delayed. A review of the current known toxicology of PZQ, combined with over two decades of clinical experience with this drug, suggest very low potential for adverse effects on either the mother or her unborn child. In contrast, significant animal and human data are presented in this review that suggest both the pregnant woman and her unborn fetus suffer morbid sequella from schistosomiasis. A double-blind placebo-controlled trial that could resolve this issue would require a very large and expensive study and in light of the above facts might not now be ethically appropriate. The author concludes that pregnant women should be treated with PZQ, that women of childbearing age should be included in all mass treatment programs and that lactating women are not systematically excluded from treatment.