Question

which substances interact with phenytoin to cause increased central nervous system (cns) depression? select all that apply. alcohol evening primrose cimetidine oral contraceptive drugs calcium - containing antacids

Explanation:

• Alcohol: Phenytoin is a CNS depressant, and alcohol also depresses the CNS. Their combined use can lead to increased CNS depression.
• Evening primrose: Does not typically interact with phenytoin to increase CNS depression.
• Cimetidine: Cimetidine can inhibit the metabolism of phenytoin, increasing its blood levels and potentially enhancing CNS depressive effects.
• Oral contraceptive drugs: Interactions with phenytoin usually involve reduced effectiveness of oral contraceptives or altered phenytoin levels, not increased CNS depression.
• Calcium - containing antacids: Can decrease the absorption of phenytoin, not cause increased CNS depression.

Answer:

A. Alcohol, C. Cimetidine