Fentanyl analogues may be hundreds of times more potent than street heroin, and tend to produce significantly more respiratory depression , making it much more dangerous than heroin to users. Fentanyl is used orally, smoked, snorted, or injected. Fentanyl is sometimes sold as heroin or oxycodone , often leading to overdoses. Many fentanyl overdoses are initially classified as heroin overdoses.  The recreational use is not particularly widespread in the EU with the exception of Tallinn, Estonia, where it has largely replaced heroin. Estonia has the highest rate of 3-methylfentanyl overdose deaths in the EU, due to its high rate of recreational use. 
All topical corticosteroids are classified category C by the US Food and Drug Administration, but some are classified category A by the Therapeutic Goods Administration ( /hp/medicines- ). Studies in animals have shown that topical steroids are systemically absorbed and may cause fetal abnormalities. Limited and inconclusive data are available for humans, however there seems to be an association between very potent topical corticosteroids and fetal growth restriction. 8 , 9 Caution is needed, but topical corticosteroids have been frequently used in pregnancy.