Reactions 917 - 31 Aug 2002

Reminder about teratogenicity ofisotretinoin

The first New Zealand case of isotretinoin-inducedteratogenicity recently reported to the Centre forAdverse Reactions Monitoring (CARM) has promptedProfessor Marius Rademaker of Waikato Hospital,Hamilton, to remind physicians about the welldocumented highly teratogenic nature of this drug.

In an article recently posted on the New ZealandMedsafe website, Professor Rademaker warns thatisotretinoin should not be used in pregnancy or wherethere is any possibility of pregnancy. He says that theevidence suggests that even a single dose of isotretinoinmay be teratogenic. Results of a US study have alsoshown a high incidence of severe malformationsassociated with isotretinoin (47% of exposed infants hadcongenital malformations and 5% had otherabnormalities), and the WHO database now contains atotal of 691 reports of isotretinoin-associated fetaldisorders, including 35 reports of multiplemalformations.

In the case report recently received by CARM, thewoman had continued taking isotretinoin 40 mg/dayduring the first 6 weeks of her pregnancy. Although anantenatal ultrasound showed no abnormalities, theneonate was born with typical retinoid embryopathywhich included malformations of the heart, ear andoesophagus.

Professor Rademaker says it is essential that all femalepatients of child-bearing potential are counselled aboutthe risks of isotretinoin on pregnancy. He advises thatpregnancy must be excluded in such patients beforetherapy, and that the patient should have been usingeffective contraception for 1 month before startingtreatment. Ideally, isotretinoin therapy should start withthe patient’s next menstrual cycle. Professor Rademakeralso says that women should undergo regular pregnancytests during treatment, and that contraception should becontinued for 1 month after stopping isotretinoin.Rademaker M. Avoiding teratogenicity with isotretinoin. Internet Document : [4pages], 22 Aug 2002 800863624

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Reactions 31 Aug 2002 No. 9170114-9954/10/0917-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved