Galen Pharmacology Exam 1 Practice Test

Phenobarbital is a long-acting CNS depressant that can produce physical dependence. Because of this dependence, stopping it abruptly can trigger withdrawal symptoms, including seizures or even status epilepticus, especially in people who have been on it long-term for seizure control. Because of the risk, abrupt discontinuation is not recommended and a gradual taper under medical supervision is usually required.

This drug does have CNS depressant effects, so the idea that it has no CNS depressant effects isn’t correct. It also interacts with other CNS depressants—combining it with alcohol, benzodiazepines, or other sedatives can markedly increase sedation and respiratory depression—and it can affect the metabolism of other drugs through enzyme induction.