Isotretinoin
Isotretinoin is a teratogen; there is about a 20–35% risk for congenital defects in infants exposed to the drug "in utero", and about 30–60% of children exposed to isotretinoin prenatally have been reported to show neurocognitive impairment. Because of this, there are strict controls on prescribing isotretinoin to women who may become pregnant and women who become pregnant while taking isotretinoin are strongly advised to terminate their pregnancies.
Actinic keratosis
Topical retinoids have been studied in the treatment of AK with modest results, and the American Academy of Dermatology does not currently recommend this as a first-line therapy. Treatment with adapalene gel daily for 4 weeks, and then twice daily thereafter for a total of nine months led to a significant but modest reduction in the number AKs compared to placebo; it demonstrated the additional advantage of improving the appearance of photodamaged skin. Topical tretinoin is ineffective as treatment for reducing the number of AKs. For secondary prevention of AK, systemic, low dose acitretin was found to be safe, well-tolerated and moderately effective in chemoprophylaxis for skin cancers in kidney transplant patients. Acitretin is a viable treatment option for organ transplant patients according to expert opinion.