When instructing a client taking phenytoin, which adverse effect should the nurse advise the client to monitor for?

Phenytoin, an anticonvulsant medication, requires careful monitoring for several potential adverse effects. One significant concern is the risk of developing a skin rash. This can be indicative of serious conditions such as Stevens-Johnson syndrome or toxic epidermal necrolysis, both of which can lead to severe skin damage and complications. Patients on phenytoin should be advised to promptly report any new or worsening rash, as early identification is crucial for intervention and preventing more severe reactions.

Other side effects like weight gain, headaches, and fatigue are not typically the primary concerns associated with phenytoin use. While they can occur, they do not carry the same level of risk for severe complications as a skin rash. Therefore, emphasizing the need to monitor for skin reactions is vital for patient safety and prompt management of any adverse effects.