Phenobarbital Oral

In Depth

Generic Name: PHENOBARBITAL - ORAL
Pronounced: (fee-no-BARB-ih-tall)

Phenobarbital Oral Side Effects

Dizziness, sleepiness, drowsiness, tiredness, loss of appetite, nausea, vomiting, or staggering walk/clumsiness may occur when you first start taking the medication, but tend to disappear over time (usually in a few weeks). Less common side effects may include headache, constipation, nightmares, and increased dreaming. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur:

mental/mood changes (e.g., confusion, agitation, hallucinations, anxiety, inability to think clearly/quickly)
slow heartbeat
fainting

Tell your doctor immediately if any of these rare but very serious side effects occur:

signs of liver problems (e.g., persistent nausea/vomiting, abdominal pain, chalky white stools, brown urine, severe tiredness, weakness, severe loss of appetite, yellow eyes/skin, itchiness)
bone pain/breaks

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including:

rash
itching/swelling (especially of the face/tongue/throat)
severe dizziness
trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Call your doctor for medical advice about side effects. In the US, you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088.

In Canada, you may report side effects to Health Canada at 1-866-234-2345.

Phenobarbital Oral Medical Alert

Your seizure condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-800-854-1166 (USA) or 1-800-668-1507 (Canada).