What does it do?

Phenobarbital is used to treat and prevent seizures.

Before you start

• Tell your doctor if you have liver problems or sleep apnoea.
• Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take phenobarbital regularly as directed. You can take it with or without food.
Tablet: Take with a glass of water.
Liquid: Measure carefully with an oral syringe or measuring spoon.

What if you forget a dose?

Take the missed dose as soon as possible and continue as directed.

Can you take other medicines?

Phenobarbital can react with many medicines, sometimes with severe results.

Remember to tell your pharmacist or doctor you are taking phenobarbital before starting any other medicines or treatments, including over-the-counter medicines, vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side Effects	Recommended action
Skin rash, skin peeling or blisters	Stop taking and see your doctor immediately
Suicidal thoughts Slow or shallow breathing, hard to wake up Reduced number of blood cells that fight infections or help your blood to clot - symptoms include: fever, chills, sore throat or generally feeling unwell, or easy or unusual bruising or bleeding Symptoms of liver problems including: yellow skin or eyes, itching, dark urine, pale bowel motions, abdominal pain	Tell your doctor immediately
Loss of co-ordination/walking or handwriting problems Confusion, trouble concentrating Unusual behaviour or thinking, mood changes, agitation	Tell your doctor
Dizziness, drowsiness	Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

• Some contraceptives may not work as well while you are taking phenobarbital, and for 4 weeks after stopping. Discuss with your doctor or pharmacist.
• Phenobarbital can impair your ability to do tasks such as driving or using machines. Alcohol makes this worse. Discuss your risk with your health professional. (search NZTA - Are you safe to drive?)
• Long-term use of phenobarbital may weaken your bones.
• Do not stop taking phenobarbital without talking to your doctor first, unless you have a skin rash (see Side Effects).