If a client with a systemic fungal infection is prescribed voriconazole, what advice should the nurse provide regarding ergot use?

The recommendation to wait until the voriconazole regimen is complete before using ergot again is based on the pharmacological interaction between these two medications. Voriconazole is an antifungal agent that is known to inhibit certain cytochrome P450 enzymes, particularly CYP3A4. Ergot derivatives, which are used mainly for migraines and various other conditions, also rely on CYP3A4 for metabolism.

When voriconazole is taken concurrently with ergot-containing medications, the inhibition of CYP3A4 can lead to increased serum levels of ergots, heightening the risk of side effects such as ergot toxicity. This can result in severe vasospasm, resulting in complications like ischemia. For patient safety, it is prudent to complete the antifungal therapy with voriconazole before reintroducing ergot medications to minimize any potential adverse interactions.

Thus, advising the client to wait until the voriconazole treatment is over ensures that any risk from potential drug interactions is effectively managed, aligning with best practices in pharmacology and patient care.