Isoniazid, tricyclics and the "cheese reaction".

Isoniazid is an antitubercular drug with some monamine oxidase (MAO) inhibition. Perhaps because this is only weak inhibition, a few clinicians consider dietary or drug restrictions for their patients on isoniazid. However recent reports suggest the combination of isoniazid and antidepressants may cause adverse events possibly related to isoniazid's MAO inhibition activity. The mechanism of the tyramine reaction and recommendations for cautious combinations of tricyclic antidepressants and isoniazid are discussed.