Is Phenobarbital A Controlled Substance?

Medically Reviewed by Johnelle Smith, M.D.

Updated on December 10, 2025

Phenobarbital is used to treat several medical conditions including seizures and anxiety. When abused, phenobarbital can have potentially life-threatening side effects, which is why it is listed as a controlled substance in the U.S.

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Phenobarbital is a barbiturate medication and a Schedule IV Controlled Substance. This drug is prescribed to treat people detoxing from addiction, as well as a treatment for people who experience panic attacks and insomnia.

While phenobarbital misuse can quickly lead to physical dependence and addiction, it still has important medical uses.

Why Phenobarbital Is A Schedule IV Controlled Substance

Drugs and other substances are considered controlled substances if they carry a risk of physical dependence or addiction. Phenobarbital can be habit-forming and addictive if abused, and is thus categorized as a Schedule IV controlled substance.

Addiction to phenobarbital can also be accompanied with physical dependence, which means a person will develop withdrawal symptoms if they suddenly stop taking the drug.

What Class Of Drug Is Phenobarbital?

Phenobarbital belongs to a class of drugs known as barbiturate anticonvulsants/hypnotics. It works by controlled electrical signals in the brain that occur during a seizure.

Phenobarbital is only intended to be used for short periods of time (typically no more than two weeks).

Is Phenobarbital Still Prescribed?

Though healthcare professionals still prescribe Phenobarbital for seizures, it is typically only given when other newer and safer seizure therapies are not working as intended. There are also availability issues in pharmacies due to manufacturing discontinuations, and unavailability of certain strengths of the drug through distributors.

Other common barbiturates include pentobarbital, secobarbital, amobarbital, methohexital, barbital, and many more.

Effects Of Phenobarbital Abuse

Misusing phenobarbital may lead to several harmful behavioral and physical side effects.

Side effects may include:

  • dizziness
  • drowsiness
  • headache
  • loss of appetite
  • nausea and vomiting
  • memory loss
  • depression
  • agitation
  • suicidal thoughts

Most people who take phenobarbital will not experience side effects, but those who do not use the drug as intended will have a much higher rate of mental and physical side effects.

Why Phenobarbital Misuse May Be Dangerous

When epilepsy drugs such as phenobarbital are abused, it can amplify the effects of other substances or prescription drugs and cause a fatal overdose.

Some of the most dangerous pharmacological phenobarbital combinations include:

  • temazepam (Restoril)
  • tramadol
  • Xanax
  • quazepam
  • oxazepam
  • Luminal
  • methylphenidate (Ritalin)
  • midazolam
  • fenfluramine
  • pentazocine
  • meperidine
  • methylphenidate
  • hydromorphone
  • carisoprodol
  • clorazepate
  • chlordiazepoxide
  • amphetamine drugs
  • buprenorphine
  • hydrocodone
  • ketamine
  • fentanyl
  • ethyl alcohol
  • anabolic steroids such as methyltestosterone

Engaging in phenobarbital drug abuse while misusing prescription opioids such as oxycodone (OxyContin), codeine, fentanyl, or hydromorphone raises the risk of overdose death substantially. Benzodiazepines and tranquilizers such as Xanax, Klonopin (clonazepam), and Valium (diazepam), may also pose dangers when mixed with phenobarbital.

In addition to the prescription drugs listed above, illicit Schedule I substances such as cannabis, methamphetamine, and heroin can also exacerbate the danger of overdose when combined with phenobarbital.

Signs Of Phenobarbital Abuse And Addiction

Recognizing the signs of phenobarbital abuse can help identify when someone needs professional help before their misuse leads to serious consequences. Physical signs include extreme drowsiness beyond normal effects, slurred speech, poor coordination, confusion, and memory problems. People abusing phenobarbital may appear intoxicated without drinking alcohol, with slow movements, difficulty focusing, and impaired judgment.

Behavioral warning signs include taking higher doses than prescribed, seeking prescriptions from multiple doctors (doctor shopping), running out of medication early, and lying about lost prescriptions. Other red flags include withdrawing from loved ones, neglecting responsibilities, mood swings, and continued use despite negative consequences. People dependent on phenobarbital may experience anxiety when their supply runs low, show drug-seeking behavior, or mix the medication with alcohol or other drugs.

If you notice these signs, seek help from a healthcare provider or addiction specialist immediately, as phenobarbital withdrawal can be dangerous and requires medical supervision.

Treatments For Phenobarbital Abuse

If you or a loved one are currently addicted to phenobarbital or other substances, an evidence-based treatment program may be able to help.

Treatment options include:

  • medication-assisted treatment (MAT)
  • medically monitored phenobarbital detox
  • individual, group, or family therapy
  • cognitive behavioral therapy
  • inpatient and outpatient care
  • dual diagnosis treatment for co-occurring disorders

Drug rehab programs that feature such treatment services will help you overcome uncomfortable withdrawal symptoms and put you on the path to recovery.

This page does not provide medical advice. See more

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