What Is A Lethal Dose Of Phenobarbital (Luminal)?

Medically Reviewed by Johnelle Smith, M.D. on July 13, 2021

Phenobarbital (Luminal) is a barbiturate drug that can be toxic and potentially lethal in very high doses. Phenobarbital overdose is treatable. This may be a sign of drug abuse.

What Is The Lethal Dose Of Phenobarbital?

Phenobarbital (Luminal) is an anti-seizure drug that belongs to a class of medications known as barbiturates. It is rarely prescribed, due to a risk of toxicity and overdose.

Phenobarbital may be prescribed as:

  • phenobarbital
  • Luminal
  • Barbital
  • Solfoton

Phenobarbital comes in the form of a liquid or tablet for use one to three times a day. Taking phenobarbital in any way other than prescribed can risk serious side effects, including overdose.

Learn more about the lethal dose of commonly abused drugs

How A Lethal Dose Of Phenobarbital Is Determined

The lethal dose of phenobarbital is between 6–10 grams, or 6,000 to 10,000 milligrams (mg).

For comparison: phenobarbital is generally prescribed in doses of 30–320 mg daily, depending on the intended use.

Taking a higher dose of phenobarbital than prescribed, or mixing it with other drugs, can lead to toxicity, or overdose. Severe cases of overdose can be fatal.

Risk Factors For Fatal Phenobarbital Overdose

Phenobarbital overdose can be more common in people who possess certain risk factors.

Risk factors for fatal phenobarbital overdose include:

  • older age
  • use of multiple drugs
  • alcohol use
  • taking multiple doses over a short period of time
  • impaired kidney or liver function
  • low body weight

Phenobarbital overdose can occur after taking very high doses alone, or with other depressants, including alcohol, opioids, or barbiturates.

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Recognizing Signs Of A Phenobarbital (Luminal) Overdose

Phenobarbital overdose can be life-threatening without prompt medical treatment. If someone you know is experiencing signs of overdose, seek medical attention right away.

Signs of a phenobarbital overdose can include:

  • low blood pressure
  • difficulty breathing
  • slowed or no breathing
  • sleepiness
  • slurred speech
  • weak pulse
  • confusion
  • large blisters
  • skin rash
  • headache
  • poor balance

Severe symptoms of overdose can include heart failure, kidney failure, and coma. Treatment for overdose may involve activated charcoal, a stomach pump, IV fluids, and airway support.

Treatment For Phenobarbital Abuse

Taking high doses of Luminal is a sign of drug abuse and addiction. Although it has medical use, Luminal can be addictive and habit-forming.

Overcoming an addiction to Luminal is possible. Call our helpline today to learn more about available treatment options for Luminal abuse and addiction.

This page does not provide medical advice. See more

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Medically Reviewed by
Johnelle Smith, M.D. on July 13, 2021
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