Use caution when prescribing baclofen off label
Recent coronial inquiries into 2 deaths have highlighted the need for health professionals to be alert to the well documented risk of overdose with baclofen.
This risk relates to intentional and unintentional overdose and is particularly pronounced when baclofen is used off label at higher doses for alcohol-use disorder. Close supervision of patients being treated with baclofen who have depression or a history of previous suicide attempts is recommended.
Warnings about this safety issue have been included in the prescribing information for baclofen since 2019.
What health professionals should do
If prescribing baclofen off label, it is important to obtain informed consent from the patient after a discussion about the benefits and risks of the medicine, particularly at higher doses.
Patients (and their carers) should be alerted to the need to monitor for clinical worsening, suicidal behaviour or thoughts, or unusual changes in behaviour. Medical advice should be sought immediately if these symptoms occur.
The registered indication for baclofen is for the suppression of voluntary muscle spasm in:
- multiple sclerosis
- spinal lesions of traumatic, infectious, degenerative, neoplastic and unknown origin, causing:
- skeletal hypertonus
- spastic and dyssynergic bladder dysfunction.
The innovator baclofen product is Lioresal, sponsored by Novartis Pharmaceuticals Australia, and there are various generics available.
The Product Information (PI) and Consumer Medicine Information (CMI) for baclofen products include warnings about the risk of suicide and suicide-related events, recommending close supervision of patients with alcohol-use disorder, depression and/or a history of previous suicide attempts.
The optimum dosage listed in the PI ranges from 30 to 75 mg daily, although occasionally doses up to 100 mg daily may be necessary in hospitalised patients. Higher dosages may be recommended for off-label use in treating alcohol-use disorder.
This safety update is only applicable to the tablet form of baclofen, not baclofen for intrathecal injection.
Off-label use of baclofen is a clinical decision. The treating clinician is responsible for obtaining informed consent from their patients following discussion of the benefits and risks, including consideration of any other treatment options available.
The TGA does not regulate medical practitioners, clinical practice or clinical guidelines. The TGA cannot guarantee the safety and efficacy of off-label use.
Warnings in the PI
4.4 SPECIAL WARNINGS AND PRECAUTIONS FOR USE
Psychiatric and nervous system disorders
Patients suffering not only from spasticity but also from psychotic disorders, schizophrenia, depressive or manic disorders or confusional states should be treated cautiously with [baclofen trade name] and kept under careful surveillance, because exacerbations of these conditions may occur.
Suicide and suicide-related events have been reported in patients treated with baclofen. In most cases, the patients had additional risk factors associated with an increased risk of suicide including alcohol use disorder, depression and/or a history of previous suicide attempts. Close supervision of patients with additional risk factors for suicide should accompany drug therapy. Patients (and caregivers of patients) should be alerted about the need to monitor for clinical worsening, suicidal behaviour or thoughts or unusual changes in behaviour and to seek medical advice immediately if these symptoms present.
Cases of misuse, abuse and dependence have been reported with baclofen. Caution should be exercised in patients with a history of substance abuse and the patient should be monitored for symptoms of baclofen misuse, abuse or dependence e.g. dose escalation, drug-seeking behaviour, development of tolerance.
4.8 ADVERSE EFFECTS (UNDESIRABLE EFFECTS)
Nervous system disorders
Not known: Cases of misuse, abuse and dependence have been reported with baclofen. Suicide and suicide-related events have been reported in patients treated with baclofen (see section 4.4 Special warnings and precautions for use – Psychiatric and nervous system disorders)
Potential for overdose
Health professionals should be alert to the risk of overdose (intentional and unintentional) in patients taking baclofen off label for alcohol-use disorder. Baclofen overdose is potentially fatal.
Cases reported to the TGA
A search of our Database of Adverse Event Notifications on 28 September 2023 using search term ‘baclofen’ and ‘overdose’ and ‘off-label use’ retrieved:
- 43 cases of overdose reported, with 23 cases as single suspect.
- 22 cases with off-label use reported, with 6 cases as single suspect.
Thompson A, Owens L, Richardson P, Pirmohamed M. Systematic review: Baclofen dosing protocols for alcohol use disorders used in observational studies. Eur Neuropsychopharmacol. 2017 Nov;27(11):1077-1089. doi: 10.1016/j.euroneuro.2017.08.434. Epub 2017 Sep 20. PMID: 28939163.
Minozzi S, Saulle R, Rösner S. Baclofen for alcohol use disorder. Cochrane Database Syst Rev. 2017 Feb 16;2017(2):CD012557. doi: 10.1002/14651858.CD012557. PMCID: PMC6464193.
Agabio R, Saulle R, Rösner S, Minozzi S. Baclofen for alcohol use disorder. Cochrane Database Syst Rev. 2023 Jan 13;1(1):CD012557. doi: 10.1002/14651858.CD012557.pub3. PMID: 36637087; PMCID: PMC9837849.
What to report? You don't need to be certain, just suspicious!
The TGA encourages the reporting of all suspected adverse reactions to medicines, including vaccines, over-the-counter medicines, herbal, traditional or alternative remedies.
We particularly request reports of:
- all suspected reactions to new medicines (look for the Black Triangle ▼ in PI and CMI documents – this symbol identifies medicines that are new or being used differently)
- all suspected medicines interactions
- suspected reactions causing death, admission to hospital or prolongation of hospitalisation, increased investigations or treatment, or birth defects.
Medicines Safety Update is aimed at health professionals. It is intended to provide practical information to health professionals on medicine safety, including emerging safety issues. The information in Medicines Safety Update is necessarily general and is not intended to be a substitute for a health professional's judgment in each case, taking into account the individual circumstances of their patients. Reasonable care has been taken to ensure that the information is accurate and complete at the time of publication. The Australian Government gives no warranty that the information in this document is accurate or complete, and shall not be liable for any loss whatsoever due to negligence or otherwise arising from the use of or reliance on this document.
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Medicines Safety Update is written by staff from the Pharmacovigilance Branch.
Editor: Dr Jessica Tidemann
Deputy Editor: Aaron Hall
Contributors: Gilbert Yeap
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