Drug Class: Barbiturates

What Are Barbiturates and How Do They Work?

Barbiturates are sedative-hypnotics, a type of central nervous system (CNS) depressant used to treat insomnia, seizures, and headaches. Barbiturates may also be used in a hospital setting for pre-operative sedation.

Barbiturates are available under the following different brand names: amobarbital (Amytal), secobarbital (Seconal), butabarbital (Butisol), pentobarbital (Nembutal), belladonna and phenobarbital (Donnatal), butalbital/acetaminophen/caffeine (Esgic, Fioricet), and butalbital/aspirin/caffeine (Fiorinal Ascomp, Fortabs).

Dosages of Barbiturates:

  • The dosages of barbiturates vary depending on the drug and its use.

Dosage Forms and Strengths

  • Amobarbital (Amytal)
    • powder for injection: 500mg
  • Secobarbital (Seconal)
  • Butabarbital (Butisol)
    • tablets: 30mg and 50mg
    • oral solution: 30 mg/5 mL

Dosage Forms and Strengths


  • Amobarbital: 30-50 mg intravenously (IV) every 8-12 hours
  • Butabarbital: 15 to 30 mg, 3 or 4 times daily

Hypnotic for short-term treatment of insomnia

Do not administer for more than 2 weeks

  • Amobarbital: 65-200 mg intravenously (IV) at bedtime
  • Secobarbital: 100 mg taken orally at bedtime

Pre-procedure Sedation

  • Secobarbital: 200-300 mg orally 1-2 hours before surgery
  • Butabarbital: 50 to 100 mg, 60 to 90 minutes before surgery

Dosage Considerations – Should be Given as Follows:

Barbiturates are classified as Schedule II substances, meaning the have definite potential for physical and psychological dependence and abuse. Barbiturates may be habit-forming. Tolerance, psychological dependence, and physical dependence may occur especially following prolonged use of high doses of barbiturates.


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What Are Side Effects Associated with Using Barbiturates?

Common side effects of barbiturates include:

Serious side effects of barbiturates include:

Rare side effects of barbiturates include:

Barbiturates have a very narrow therapeutic index, meaning small differences in dose can result in big differences in the effects of the drug and patients can easily develop side effects. Combining barbiturates with other drugs such as opioids, benzodiazepines, antidepressants, or over-the-counter (OTC) medications with antihistamines could be fatal.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Barbiturates?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Drug interactions of barbiturates include:

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.


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What Are Warnings and Precautions for Barbiturates?


This medication contains barbiturates. Do not take barbiturates if you are allergic to amobarbital (Amytal), secobarbital (Seconal), butabarbital (Butisol), pentobarbital (Nembutal), belladonna and phenobarbital (Donnatal), butalbital/acetaminophen/caffeine (Esgic, Fioricet), and butalbital/aspirin/caffeine (Fiorinal Ascomp, Fortabs) or any ingredients contained in these drugs.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


Effects of Drug Abuse

  • Withdrawal symptoms may occur if you suddenly stop taking barbiturates. Withdrawal symptoms for barbiturates may include restlessness, agitation, anxiety, nausea, vomiting, insomnia, weakness, fast heart rate, tremors (shaking), hallucinations, or seizures.

Short-Term Effects

  • See "What Are Side Effects Associated with Using Barbiturates?"

Long-Term Effects

Barbiturates may cause physical or mental dependence when taken over long periods. Signs of dependence include:

  • Needing to take larger doses of the medicine to get the same effect
  • A compulsion to keep taking the medicine
  • Withdrawal symptoms, such as nausea or vomiting, anxiety, sleep problems, convulsions, or tremors (shaking) when the medicine is stopped


  • Barbiturates are central nervous system depressants and should not be taken with alcohol or other drugs that slow the central nervous system, such as antihistamines, cold and allergy medicines, sleep medications, tranquilizers, medicine for seizures, narcotics, and muscle relaxants. Combining CNS depressants can lead to unconsciousness or death.
  • Barbiturates may alter the results of some medical tests.
  • Barbiturates may cause drowsiness, dizziness, lightheadedness, or decreased alertness. These side effects may be present the morning after taking a barbiturate at bedtime. Do not drive, use machines, or do anything else that could be dangerous until you know how barbiturates affect you.
  • Children may be more sensitive to barbiturates and have additional side effects such as unusual excitement.
  • Older people and those who are very ill may also be more sensitive to barbiturates and have additional side effects such as confusion, depression, and unusual excitement.
  • Barbiturates should be administered with caution, if at all, to patients who are mentally depressed, have suicidal tendencies, or a history of drug abuse.

Pregnancy and Lactation

  • Barbiturates should not be used during pregnancy; they may harm a fetus. Withdrawal symptoms occur in infants born to mothers who receive barbiturates in the last trimester of pregnancy.
  • Small amounts of some barbiturates pass into breast milk. Barbiturates are not recommended for use while breastfeeding to avoid harm to the infant.
Medscape. Barbiturate Toxicity.
Medscape. Barbiturate Levels.
NIH. Livertox. Barbiturates.
Medscape. Amobarbital.
Medscape. Secobarbital.

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