Is it safe to use albendazole during late pregnancy?/nA 25-year-old woman, six months pregnant, has

Fråga: Is it safe to use albendazole during late pregnancy?

A 25-year-old woman, six months pregnant, has echinococcosis. Treatment with albendazole is considered.

Sammanfattning: Albendazole passes the placenta and is teratogenic in several animal species. In late pregnancy, this risk is probably small. It is not known whether albendazole has toxic effects on the fetus, and only two case reports of human fetal exposition were found. One of them ended in premature birth, but both children were healthy. Since the effects of albendazole on the fetus in late pregnancy are uncertain and small hydatid cysts seldom result in obstetric complications, it seems reasonable to postpone treatment until after delivery if possible.

Svar: A question about albendazole and pregnancy has previously been answered in Drugline (1). Use of albendazole during pregnancy was not recommended, although coincidental use was not considered a major reason for abortion. Large hydatid cysts in pregnancy are rare with an incidence of 1/20000 even in endemic areas (2). Small cysts do not interfere with normal pregnancy and labour, while large cysts should be removed because of the risk of rupture (2).

An updated search revealed two new case reports of albendazol medication in pregnant women. A 20-year-old woman was treated with albendazole 10 mg/kg daily for echinococcus cysts during the third trimester and delivered a healthy boy two weeks before estimated date of delivery (3). Another woman with the same diagnosis underwent cystectomy in the nineteenth week of pregnancy, under peroperative treatment with albendazole. She delivered a premature but otherwise healthy boy at 33 weeks (4).

Albendazole is known to be teratogenic in several animal species, even in doses commonly used in clinical practice (5-6). In rats it has been shown to have fetotoxic effects in doses above 6 mg/kg (5). In cows, single doses of 25 mg/kg in the last three months of gestation did not induce abortion (7). No human teratogenicity data exist, but based on the animal studies, pregnancy is considered a contraindication (5-6).

The antihelminthic drug netobimin is metabolised to albendazole. In two animal studies albendazole and its metabolites were found in the amniotic fluid and umbilical blood after administration of netobimin to the mother (8-9). The concentrations were more than 50 percent of the maternal plasma concentrations. The passage of albendazole itself has not been studied, but since it is known to be teratogenic in animals, it seems obvious that it is capable of passing the placental barrier. 1 Drugline no 09156 (year 1991) 2 Rahman MS, Rahman J, Lysikiewicz A: Obstetric and gynaecological presentations of hydatid disease. Br J Obstetr Gynaecol 1982; 89: 665-670 3 Vliet W van, Scheele F, Sibinga-Mulder L, Dekker GA: Echinococcosis of the liver during pregnancy, Int J Gynecol Obstetr 1995; 49: 323-324 4 Golaszewski T, Susani M, Golaszewski S, Sliutz G, Bischof G, Auer H: A large hydatid cyst of the liver pregnancy. Arch Gynecol Obstet 1995; 256: 43-47 5 Dollery C Sir, editor. Therapeutic drugs. 2nd ed. Edinburgh: Churchill Livingstone; 1998 6 Parfitt K, editor. Martindale, The complete drug reference. 32nd ed. London: Pharmaceutical Press; 1999 7 Theodorides VJ, Carakostas MC, Colaianne JJ, Freeman JF, Page SW: Safety of albendazole in developing bovine fetuses. Am J Vet Res 1993; 54: 2171-4 8 Christofol C, Navarro M, Franquelo C, Valladares JE, Carretero A, Ruberte J, Arboix M: Disposition of netobimin, albendazole, and its metabolites in the pregnant rat: developmental toxicity. Toxicol Appl Pharmacol 1997; 144: 56-61 9 Cristofol C, Carretero A, Fernandez M, Navarro M, Sautet J, Ruberte J, Arboix M: Transplacental transport of netobimin metabolites in ewes. Eur J Drug Metab Pharmacokinet 1995; 20: 167-171