Toxicological considerations in the prescription of baclofen for the treatment of substance use disorders

ABSTRACT

Introduction: For many years, applications for baclofen have widened in the treatment of substance abuse disorder (SUD), mainly alcohol use disorder, with a growing rate of off-label prescriptions in Europe. Clinical effects seem to be both a decrease of craving and anxiety, leading to a decrease of drug or alcohol consumption. We described baclofen poisoning circumstances, therapeutic options and outcomes when used in substance use disorders.

Areas covered: This review summarizes the toxicological considerations where baclofen was prescribed in humans for substance use or abuse disorder in randomized clinical trials, case series, case reports and observational studies between 1990 and 2020 according to the Preferred Reporting Items for Systemic reviews and Meta-Analysis.

Expert opinion: The most frequent cause of severe intoxication is self-poisoning. A dose above 180 mg are expected to cause severe toxicity and death. The treatment is only symptomatic as no antidote is available. Off-label prescription remains unsafe because the optimal dose is not known and varies greatly between patients. As SUD are frequently associated with psychiatric disorders and such patients may have suicidal thoughts, the risk of self-poisoning is high. Potential co-ingestants should also be considered, especially CNS depressants, and they need to be closely monitored.

KEYWORDS:

• Poisoning
• baclofen
• alcohol use disorder
• substance use disorder

Article highlights

• For many years, applications for baclofen have been developing in the treatment of alcohol use disorder, and some SUD.

• CNS and respiratory depression are the main symptoms following acute baclofen overdose with prolonged coma and seizures, with some deaths reported.

• Cessation of long-term baclofen administration may cause severe withdrawal syndrome.

• A daily dose higher than 180 mg can be proposed as a limit beyond which additional precautions should be taken, such as close monitoring

• SUD is frequently associated with psychiatric disorders, and such patients are particularly at risk of self-poisoning with co-ingestants

• Before prescribing baclofen, physicians should discuss the benefit-risk ratio and should control renal function.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.