Since the introduction of astemizole preparations into the market in 1988, adverse reactions associated with the drug has required a series of labelling changes and warnings. Amongst these changes are warnings of irregular heart rhythms or severe allergic reactions if taken at higher-than-recommended doses or in conjuction with some other drugs, including antihypertensives, anti-asthmatics, anti-HIV/AIDS drugs as well as some antibiotics.

In the US, Hismanal has been voluntarily withdrawn from the market. The US Food Drug Administration (FDA) supported this withdrawal in the light of availability of other antihistamines and the overall risk benefit profile of astemizole.

In Singapore, the Ministry has also decided to de-register all products containing astemizole. The product licences for all astemizole preparations will be revoked on 31 Jul 2000. Product licences which expire before this date will not be renewed. New product licence applications for astemizole would also not be approved.