Which of the following is NOT listed as a side effect of phenytoin?

• A. Nausea
• B. Gingival hyperplasia
• C. Slurred speech
• D. Stevens-Johnson syndrome

Answer: (A)

Phenytoin’s adverse-effect profile includes several well-recognized reactions tied to its long-term CNS and dermatologic impacts. Gingival hyperplasia is a classic, dose-related change involving gum overgrowth. Slurred speech reflects CNS effects such as ataxia or cerebellar toxicity, especially with higher levels or rapid dosing changes. Stevens-Johnson syndrome is a known, though rare, serious hypersensitivity reaction associated with anticonvulsants, including phenytoin. Nausea, while possible with many drugs, is not typically listed as a distinct adverse effect of phenytoin in standard references. The question tests your ability to identify the effects that are emphasized in standard phenytoin safety profiles, making nausea the option not listed, while the other three fit the established adverse-effect pattern.