What is the protocol for tapering Phenobarbital (phenobarbital) in a patient with alcohol use disorder?

From the Guidelines

Phenobarbital taper in alcoholic patients should be approached with caution and typically referred to a specialist, if possible, due to the risks of increased anxiety and depression symptoms, seizures, and altered mental status 1. When considering a phenobarbital taper, it's essential to assess the patient's motivation, adherence, and medical history.

• Patients with a history of withdrawal seizures or other medical comorbidities should generally be referred to a specialist.
• A slow taper over months may be attempted in selected patients with dependence and a reliable history of benzodiazepine use.
• Risks of tapering benzodiazepines, which may also apply to phenobarbital, include increased anxiety and depression symptoms, seizures, and altered mental status 1. Key considerations for a phenobarbital taper include:
• Monitoring the patient closely for withdrawal symptoms using a validated scale.
• Ensuring adequate hydration, vitamin supplementation (especially thiamine), and supportive care.
• Being vigilant for signs of respiratory depression, especially if the patient has liver impairment or is taking other sedating medications. Given the potential risks and complexities involved, a referral to a specialist is often the most appropriate course of action for managing phenobarbital taper in alcoholic patients 1.

From the FDA Drug Label

Treatment of barbiturate dependence consists of cautious and gradual withdrawal of the drug Barbiturate-dependent patients can be withdrawn by using a number of different withdrawal regimens. In all cases, withdrawal takes an extended period of time. One method involves substituting a 30 mg dose of phenobarbital for each 100 to 200 mg dose of barbiturate that the patient has been taking The total daily amount of phenobarbital is then administered in 3 to 4 divided doses, not to exceed 600 mg daily. Should signs of withdrawal occur on the first day of treatment, a loading dose of 100 to 200 mg of phenobarbital may be administered IM in addition to the oral dose After stabilization on phenobarbital, the total daily dose is decreased by 30 mg a day as long as withdrawal is proceeding smoothly. If withdrawal symptoms appear, dosage is maintained at that level or increased slightly until symptoms disappear A modification of this regimen involves initiating treatment at the patient’s regular dosage level and decreasing the daily dosage by 10 percent if tolerated by the patient.

For a phenobarbital taper in an alcoholic, the following steps can be taken:

• Substitute 30 mg of phenobarbital for each 100-200 mg of barbiturate the patient has been taking.
• Administer the total daily amount of phenobarbital in 3-4 divided doses, not exceeding 600 mg daily.
• Decrease the total daily dose by 30 mg per day as long as withdrawal is proceeding smoothly.
• If withdrawal symptoms appear, maintain the dosage at the current level or increase it slightly until symptoms disappear.
• Alternatively, initiate treatment at the patient's regular dosage level and decrease the daily dosage by 10 percent if tolerated by the patient 2.

From the Research

Phenobarbital Taper in Alcoholic Patients

• The use of phenobarbital in managing alcohol withdrawal syndrome (AWS) has been studied in several research papers 3, 4, 5, 6, 7.
• A review of the literature found that phenobarbital dosing regimens can be effective in improving AWS symptoms, decreasing intensive care unit and hospital length of stay, and preventing seizures 3.
• A study comparing fixed-dose phenobarbital with as-needed benzodiazepines found that phenobarbital was associated with a lower incidence of delirium and trends toward lower mortality, ICU transfer, and seizure rates 4.
• Another study found that patients treated with phenobarbital had similar primary and secondary treatment outcomes to those treated with benzodiazepines, despite being more likely to have a history of prior complications related to AWS 5.
• A retrospective cohort study found that phenobarbital was associated with a significantly decreased risk of respiratory complications, including intubation and pneumonia, compared to benzodiazepines 6.
• A register-based cohort study found that phenobarbital treatment was associated with decreased mortality, but no decreased risk of subsequent benzodiazepine use or alcohol recidivism, compared to chlordiazepoxide treatment 7.

Key Findings

• Phenobarbital can be an effective alternative to benzodiazepines for managing AWS 3, 4, 5, 6.
• Phenobarbital may be associated with a lower risk of delirium and respiratory complications compared to benzodiazepines 4, 6.
• Phenobarbital treatment may be associated with decreased mortality, but the evidence is mixed 5, 7.

Phenobarbital Taper Regimens

• The optimal phenobarbital taper regimen for alcoholic patients is not well established, but fixed-dose and weight-based dosing strategies have been studied 3.
• A parenteral phenobarbital loading dose with an oral phenobarbital tapered protocol may be effective in reducing the risk of respiratory complications 6.