[Adverse drug effects in the oral region].

Syphilis was previously termed "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases. This role has been taken over by drugs, and this also applies to adverse drug reactions in the oral region. Accordingly, a careful drug history, including identification of any prescription, over-the-counter, or herbal medicines used, may give an important clue to the differential diagnosis of oral diseases when the aetiology is not apparent. Virtually all drugs have the potential to cause oral adverse reactions, but some have a greater ability to do so than others. Among the numerous adverse oral manifestations are xerostomia, taste disturbances and ulceration. The reactions are often non-specific, but they may mimic specific disease states such as erythema multiforme, lichen planus and pemphigus. Drug-induced gingival hyperplasia is an example of a quite characteristic and easily recognisable oral side effect. This article briefly describes some of the presentations and mechanisms of oral manifestations of drug therapy and the drugs that most commonly are responsible. Just like approved pharmaceuticals, herbal medicines are also associated with adverse oral manifestations. Finally we comment on some of the more recent reports on osteonecrosis of the jaws associated with the use of bisphosphonates.