Brand Name(s):

  • Nembutal®
  • Nembutal®Sodium
  • Nembutal®Sodium Solution


Pentobarbital capsules, liquid, and suppositories are no longer available in the U.S.

WHY is this medicine prescribed?

Pentobarbital, a barbiturate, is used in the short-term treatment of insomnia (to help you fall asleep and stay asleep for a proper rest). It is also used as a sedative to relieve anxiety and induce sleep before surgery.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Pentobarbital comes as a capsule and liquid to take by mouth and as a suppository to be used rectally. The capsule or liquid is taken at bedtime as needed for insomnia or two to four times a day for anxiety. Take pentobarbital on an empty stomach, at least 1 hour before or 2 hours after meals. The suppositories are inserted at bedtime as needed for insomnia or two to four times a day for anxiety. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take pentobarbital exactly as directed.

Pentobarbital can be habit-forming; do not take a larger dose, take it more often, or for a longer time than your doctor tells you to. Do not stop taking pentobarbital without talking to your doctor, especially if you have taken large doses for a long time. Your doctor probably will decrease your dose gradually.

To insert a pentobarbital suppository, follow these steps:

  • Remove the wrapper.
  • Dip the tip of the suppository in water.
  • Lie down on your left side and raise your right knee to your chest. (A left-handed person should lie on the right side and raise the left knee.)
  • Using your finger, insert the suppository into the rectum, about 1/2 to 1 inch (1.25 to 2.5 centimeters) in infants and children and 1 inch (2.5 centimeters) in adults. Hold it in place for a few moments.
  • Stand up after about 15 minutes. Wash your hands thoroughly and resume your normal activities.

What SPECIAL PRECAUTIONS should I follow?

Before taking pentobarbital,

  • tell your doctor and pharmacist if you are allergic to pentobarbital, aspirin, tartrazine (a yellow dye in some processed foods and drugs), or any other drugs.
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially acetaminophen (Tylenol), antihistamines, chloramphenicol (Chloromycetin), digitoxin (Crystodigin), diuretics ('water pills'), doxycycline (Vibramycin), griseofulvin (Grisactin), medications for depression or seizures, metronidazole (Flagyl), oral contraceptives, propranolol (Inderal), quinidine, rifampin, sedatives, sleeping pills, steroids (for asthma), theophylline (Theo-Dur), tranquilizers, and vitamins.
  • tell your doctor if you have a fever or pain or if you have or have ever had liver or kidney disease, asthma, hyperthyroidism, diabetes, anemia, a history of alcoholism or drug abuse, or heart or lung problems.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking pentobarbital, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking pentobarbital.
  • you should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how this drug affects you.
  • remember that alcohol can add to the drowsiness caused by this drug.

What should I do IF I FORGET to take a dose?

Do not take a missed dose when you remember it. Skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Pentobarbital may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • drowsiness
  • headache
  • depression
  • excitement
  • joint or muscle pain
  • upset stomach
  • diarrhea
  • constipation

If you experience any of the following symptoms, call your doctor immediately:

  • skin rash
  • itching
  • sore throat
  • fever
  • easy bruising
  • bloody nose
  • unusual bleeding

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

What OTHER INFORMATION should I know?

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: June 1, 2010.