pentobarbital (injection)

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Pronunciation: PEN toe BAR bi tal

Brand: Nembutal Sodium

What is the most important information I should know about pentobarbital?

You should not use this medicine if you have a history of porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system).

What is pentobarbital?

Pentobarbital is a barbiturate (bar-BIT-chur-ate). Pentobarbital slows the activity of your brain and nervous system.

Pentobarbital is used short-term as a sedative to treat insomnia, or to cause you to fall asleep for surgery. Pentobarbital is also used as an emergency treatment for seizures.

Pentobarbital may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before using pentobarbital?

You should not use this medicine if you are allergic to pentobarbital or other barbiturates (butabarbital, phenobarbital, Luminal, Seconal, and others), or if you have:

  • a history of porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system).

To make sure pentobarbital is safe for you, tell your doctor if you have:

  • liver disease;
  • kidney disease;
  • temporary or chronic pain;
  • a history of addiction to phenobarbital or similar medicines (Valium, Xanax, Ativan, and others).

Using pentobarbital during pregnancy could harm the unborn baby. If you use pentobarbital while you are pregnant, your baby could become dependent on the drug. This can cause life-threatening withdrawal symptoms in the baby after it is born. Babies born dependent on habit-forming medicine may need medical treatment for several weeks. Tell your doctor if you are pregnant or plan to become pregnant.

Pentobarbital can make birth control pills less effective. Ask your doctor about using a non-hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy.

Pentobarbital can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How is pentobarbital given?

Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Pentobarbital may be habit-forming. Never share pentobarbital with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it. Selling or giving away this medicine is against the law.

Pentobarbital is injected into a muscle, or into a vein through an IV. A healthcare provider will usually give you this injection.

You may be shown how to use pentobarbital at home. Do not give yourself this medicine if you do not understand how to use the injection and properly dispose of needles, IV tubing, and other items used.

When injected into a vein, pentobarbital must be given slowly.

Your breathing, blood pressure, oxygen levels, kidney function, and other vital signs will be watched closely after you receive pentobarbital in a hospital setting.

Do not use pentobarbital if it has changed colors or has particles in it. Call your pharmacist for new medication.

Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.

If you use this medicine long-term, you may need frequent medical tests.

Do not stop using this medicine suddenly after long-term use, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using pentobarbital.

Store at room temperature away from moisture and heat. Do not freeze.

What happens if I miss a dose?

Since pentobarbital is often used only when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine. An overdose of pentobarbital can be fatal.

Overdose symptoms may include extreme drowsiness, weak or limp feeling, slow or shallow breathing, weak pulse, rapid heart rate, little or no urination, pinpoint or dilated pupils, feeling cold, or fainting.

What should I avoid while taking pentobarbital?

Pentobarbital can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Do not drink alcohol. Dangerous side effects can occur when alcohol is combined with pentobarbital.

What are the possible side effects of pentobarbital?

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • confusion, agitation, hallucinations;
  • weak or shallow breathing;
  • slow heart rate, weak pulse; or
  • a light-headed feeling, like you might pass out.

Side effects such as confusion, depression, or excitement may be more likely in older adults and those who are ill or debilitated.

Common side effects may include:

  • drowsiness, dizziness;
  • loss of balance or coordination;
  • nausea, vomiting, constipation;
  • overactive reflexes;
  • sleep problems (insomnia), nightmares; or
  • feeling restless or excited (especially in children or older adults).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect pentobarbital?

Using this medicine with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before receiving pentobarbital if you regularly use sleeping pills, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Tell your doctor about all other medications you use, especially:

  • doxycycline;
  • griseofulvin;
  • birth control pills or hormone replacement estrogens;
  • a blood thinner --warfarin, Coumadin, Jantoven;
  • an MAO inhibitor --isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others;
  • other seizure medications --divalproex, phenytoin, valproic acid (Depakene); or
  • steroid medicine --prednisone, dexamethasone, prednisolone, and others.

This list is not complete. Other drugs may interact with pentobarbital, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

Your doctor or pharmacist can provide more information about pentobarbital.


Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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