Baclofen-related deaths in Australia 2000-2022.

In Australia, the therapeutic indication of baclofen (oral tablets) is for the treatment of muscle spasm. Deaths related to baclofen have been reported, as well as misuse, dependence and self-poisoning. This national retrospective study aimed to investigate the number, characteristics, circumstances, and toxicology of baclofen-related deaths in Australia, 2000-2022. We identified 102 baclofen-related deaths, with a mean age of 45.6 years and 51 % being male. Circumstances of death were: intentional toxicity (54.9 %), unintentional toxicity (30.4 %), unintentional toxicity/disease (9.8 %), and accidental injury (4.9 %). Multiple sclerosis or spinal injury was documented in 15.7 % of cases, substance use problems in 43.1 % and specifically alcohol use problems in 38.2 %. Mental health problems were documented in 73.5 %, a previous self-harm or suicide attempt in 30.4 %, and chronic pain in 37.3 %. The median baclofen blood concentration for all cases was 3.10 mg/L (25th 0.70, 75th 8.10, range 0.04-110.00), unintentional toxicity 1.95 mg/L (25th 0.70, 75th 4.35, range 0.04-24.0), intentional toxicity 6.00 mg/L (25th 1.10, 75th 13.0, range 0.05-110.0). Concomitant substance use was seen in 93.8 %, with antidepressants (69.8 %) and benzodiazepines (64.6 %) most frequently detected. In conclusion, the 'typical' case was middle-aged, most dying due to intentional toxicity, and likely to have a history of mental health and substance use problems. We suggest caution is needed in prescribing baclofen given its potential to be used in intentional and non-intentional overdose.