The need to maintain long-term treatment of chronic pathologies makes the appearance of interactions possible when such therapies incorporate other drugs to deal with the aggravation of the same or other intercurrent pathologies. A case is presented in which the addition of trazodone to a chronic treatment with carbamazepine (CBZ) is associated with symptoms typical for intoxication by this antiepileptic, accompanied by a raised serum concentration. When the trazodone was suspended, these symptoms lessened and the concentration of CBZ decreased progressively, suggesting a probable interaction between the 2 drugs.
The addition of voriconazole to chronic treatment with carbamazepine 400 mg twice a day was associated with increased carbamazepine serum levels (14.1 mg/l) and serum concentration dose ratios. Three days after the voriconazole was started, this ratio doubled its value to 1. Carbamazepine concentration as well as serum concentration dose ratio gradually decreased after treatment with voriconazole was discontinued, suggesting a probable interaction between the two drugs, according to the drug interaction probability scale. Although no clinical toxicity appeared with carbamazepine, the interaction can be considered severe and potentially toxic: early detection, suspension of carbamazepine and dose adjustment prevented such harm in this case. The likely mechanism is that voriconazole decreases carbamazepine metabolism.To our knowledge this is the first reported case of interaction between voriconazole, as precipitant drug, and carbamazepine, as object drug. The interaction is not referenced in clinical databases as published cases, but as a foreseeable interaction.Publication of this first clinical case reinforces the need of using both drugs associated with caution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.