PDR Health


What is Phenobarbital?

Phenobarbital is a long-acting barbiturate. It is used as an anticonvulsant and sedative.


Health Benefits

Phenobarbital has a number of potential health benefits, including:

1. Reducing seizures: Phenobarbital is commonly used to treat epilepsy and other seizure disorders. It works by decreasing the activity of nerve cells in the brain.

2. relieving anxiety: Phenobarbital can help to relieve anxiety and promote relaxation.

3. inducing sleep: Phenobarbital is often used as a sedative to help people fall asleep.

4. alleviating pain: Phenobarbital can be used to alleviate pain, particularly when it is combined with other pain medications.

5. reducing fever: Phenobarbital can also help to reduce fever.

Side Effects

What are the side effects of Phenobarbital?

The most common side effects of phenobarbital include: drowsiness, dizziness, lightheadedness, nausea, vomiting, loss of coordination, and blurred vision. More serious side effects may include: depression, difficulties with thinking or memory, and problems with movement.


What is the recommended dosage of Phenobarbital?

The recommended dose of phenobarbital depends on the individual and the condition being treated. For epilepsy, the usual starting dose is 15 mg/kg per day, divided into 2 or 3 doses. For insomnia, the usual dose is 100-200 mg at bedtime.


What drugs or supplements interact with Phenobarbital?

Phenobarbital can interact with a number of other drugs and supplements, including: alcohol, barbiturates, benzodiazepines, cimetidine, MAO inhibitors, and warfarin.

Phenobarbital should not be used with alcohol or other central nervous system depressants. These substances can potentiate the sedative effects of phenobarbital and increase the risk of respiratory depression.

Cimetidine can increase the levels of phenobarbital in the blood. This may increase the sedative effects of phenobarbital and increase the risk of side effects.

MAO inhibitors can interact with phenobarbital and increase the risk of side effects.

Warfarin (Coumadin) is a blood thinner that can interact with phenobarbital. Phenobarbital can increase the levels of warfarin in the blood, which may increase the risk of bleeding.

Mechanism of Action

How does Phenobarbital work?

Phenobarbital works by depressing the central nervous system. It does this by binding to a specific receptor in the brain known as the GABA receptor. This results in an increase in the activity of GABA, a neurotransmitter that inhibits nerve cell activity. As a result, phenobarbital can help to reduce seizures and induce sleep.


What is the pharmacokinetics of Phenobarbital?

Phenobarbital is absorbed quickly from the gastrointestinal tract and reaches peak levels in the blood within 1-2 hours. It is then metabolized in the liver and excreted in the urine. The half-life of phenobarbital is 36-72 hours.

Alternatives to Phenobarbital

What are the alternatives to Phenobarbital?

There are a number of alternatives to phenobarbital, including: other anticonvulsants such as carbamazepine and valproic acid; sedatives such as diazepam and zolpidem; and alternative therapies such as acupuncture and yoga.

How long does it take to work?

The effects of phenobarbital can be felt within 30-60 minutes.

How long does it last?

The effects of phenobarbital typically last for 4-6 hours.