What Are Phenobarbital Tablets Used For?

Doctors typically prescribe phenobarbital tablets to control seizures, according to MedlinePlus. It is also sometimes used to treat anxiety and prevent withdrawal symptoms in patients who are stopping another barbiturate medication.

As of 2015, phenobarbital is the oldest epilepsy medication still in use, states the Epilepsy Foundation. Inexpensive and effective, phenobarbital is used to treat temporal lobe epilepsy, Lennox-Gastaut syndrome, Rasmussen's syndrome, refractory seizures, tonic seizures and clonic seizures.

The most common side effects of phenobarbital are fatigue and tiredness, states the Epilepsy Foundation. Other side effects include depression, memory problems, decreased sexual desire and anemia. Additionally, taking phenobarbital can increase risk of suicide.

Phenobarbital is habit-forming, and withdrawal symptoms include increased anxiety, shaking, dizziness, nausea and vomiting, notes MedlinePlus. Other withdrawal symptoms include muscle twitching, confusion, changes in vision and difficulty sleeping. To avoid withdrawal symptoms, patients should decrease the medication gradually.

Phenobarbital should be stored at room temperature out of the reach of children, states the Epilepsy Foundation. Patients can take phenobarbital with or without food, but it's best to stay consistent. Most patients take phenobarbital once per day. If phenobarbital causes sleepiness or excess fatigue when taken during the day, it can be taken 30 to 60 minutes before bedtime.