Phenobarbital Abuse & Important Side Effects

Phenobarbital is a barbiturate medication used to treat several conditions, including seizures, anxiety, panic attacks, and insomnia. Sometimes, phenobarbital is prescribed to treat people detoxing from addiction to other types of barbiturates. While this potent drug is not often prescribed for anxiety or insomnia anymore, it still has important medical uses. However, it can also rapidly lead to abuse, physical dependence, and addiction.

Phenobarbital Abuse


Barbiturate misuse and addiction, including to phenobarbital, peaked in the 1960s and 1970s. Since then, aside from a brief spike in the 1990s, misuse of sedatives like phenobarbital has been declining. These medicines are no longer recognized as the safest treatment for conditions like insomnia or anxiety, and other classes of drugs, including benzodiazepines and sedative-hypnotic sleep aids, are prescribed more often.

Phenobarbital is still occasionally prescribed, especially in veterinary practices, to treat some conditions like seizure disorders. This medication can be habit-forming, especially if the drug is taken for long periods of time or in higher amounts than prescribed. Individuals who misuse phenobarbital can develop a tolerance, and need increasing amounts to feel the same effects.

These drugs are also still diverted, illicitly manufactured, and sold specifically to be abused. In 2010, there were a reported 1,493 emergency room visits in the United States due to barbiturate overdoses, including phenobarbital; these overdoses resulted in 396 deaths. In 2020, barbiturate overdoses accounted for over 1300 calls to poison control centers.

Short-Term Side Effects from Phenobarbital

Even when a person takes phenobarbital as prescribed and is overseen by a medical professional, they may experience side effects from this potent drug. People who use phenobarbital for non-medical reasons are at greater risk for side effects, which are likely to last longer and become chronic.

Short-term side effects from phenobarbital include:

  • Loss of coordination or dizziness.
  • Headaches.
  • Drowsiness.
  • Nausea or vomiting.
  • Upset stomach.
  • Trouble concentrating.
  • Memory difficulty.
  • Excitement, irritability, confusion, or aggression.
  • Depression.
  • Slurred speech.
  • Anemia.
  • Rash.
  • Fever.
  • Vitamin or calcium deficiencies, which could lead to chronic physical ailments.

Long-Term Side Effects and Chronic Health Challenges from Phenobarbital

A person may experience chronic changes or long-term side effects from use of phenobarbital. These may include joint pain, or thickening of the soft tissues in areas like the palm or the bottom of the foot. Osteoporosis and osteopenia (loss of bone mass and failure to regrow bone tissue) may also occur with long-term use of phenobarbital. This increases the risk of fractures.

When a person suddenly stops taking phenobarbital they may develop a seizure disorder. When they attempt to withdraw from the drug, even with medical assistance, the risk of having a seizure increases. This is especially true for high-dose, long-term phenobarbital addiction. This is why it’s important to seek help from a healthcare professional. Our medical detox facility in Riverview, FL can help you when you’re ready to stop using phenobarbital.

Phenobarbital Overdose

It is possible to overdose on phenobarbital, especially if one struggles with addiction to the drug. A lethal dose of phenobarbital is 6-10 grams, which a person may have in their medicine cabinet if they have a prescription. As a daytime sedative, a doctor may prescribe anywhere from 30 mg to 120 mg. As an insomnia treatment, an individual could take as much as 320 mg. Most phenobarbital overdoses in the US are ruled suicide attempts, but several of them involve substance use disorders.

Signs of a phenobarbital overdose include:

  • Uncontrollable eye movements.
  • Loss of coordination.
  • Slowed or irregular breathing.
  • Feeling cold to the touch due to a drop in body temperature.
  • Blisters appearing.

Other signs of intoxication, leading to overdose, may include:

  • Changes to consciousness or alertness.
  • Trouble thinking or confusion.
  • Drowsiness.
  • Staggering.
  • Lack of physical coordination.
  • Shallow, irregular, depressed, or stopped breathing.
  • Slurred or slow speech.
  • Sluggishness.
  • Changes in mood, especially irritability or aggression.
  • Memory loss or blackouts.
  • Coma.

Withdrawal Symptoms from Phenobarbital

People who have developed a physical dependence on phenobarbital, even if it is taken as prescribed, may experience withdrawal symptoms if they suddenly stop taking it.

These symptoms include:

  • Rebound anxiety and insomnia.
  • Uncontrollable shaking.
  • Increased heart rate.
  • Muscle twitches.
  • Dizziness or loss of coordination.
  • Physical weakness.
  • Changes to vision.
  • Nausea or vomiting.
  • Difficulty falling or staying asleep.
  • Hyperthermia, or dangerously high body temperature.
  • Hallucinations.
  • Seizures.

Phenobarbital Addiction Treatment

Treating phenobarbital addiction is similar treating alcohol or benzodiazepine addiction. Working closely with a medical professional to develop a taper schedule. This enables doctors and addiction treatment specialists to ween the person from physical dependence on the drug, and monitor for long-term damage to the person’s health.

It’s important to note that detox is just the first step in the recovery process and is not a standalone treatment. It’s generally recommended that the person enters treatment for substance use disorders. For people struggling with chronic health problems due to phenobarbital addiction, inpatient rehabilitation and long-term medical treatment are often required.

Inpatient Addiction Treatment near Tampa

River Oaks Treatment Center is ready to help you overcome addiction and find long-term recovery. Call our helpful admissions navigators at to learn more about our addiction treatment options, how to cover the cost of rehab, about our Tampa Bay inpatient rehab, and getting started with the admissions process.

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