Oral Muscle Relaxants for the Treatment of Chronic Pain Associated with Cerebral Palsy

Abstract

Purpose of review: This is a comprehensive literature review of the available for treatment of oral muscle relaxants for cerebral palsy (CP) and associated chronic pain. It briefly describes the background and etiology of pain in CP and proceeds to review and weigh the available evidence for treatment for muscle relaxants.

Recent findings: CP is a permanent, chronic, non-progressive neuromuscular and neurocognitive disorder of motor dysfunction that is diagnosed in infancy and is frequently (62% of patients) accompanied by chronic or recurrent muscular pain. Treatment of pain is crucial, and focuses mostly on treatment of spasticity through non-interventional techniques, surgery and medical treatment. Botulinum toxin injections provide temporary denervation, at the cost of repeated needle sticks. More recently, the use of oral muscle relaxants has gained ground and more evidence are available to evaluate its efficacy. Common oral muscle relaxants include baclofen, dantrolene and diazepam. Baclofen is commonly prescribed for spasticity in CP; however, despite year-long experience, there is little evidence to support its use and evidence from controlled trials are mixed. Dantrolene has been used for 30 years, and very little current evidence exists to support its use. Its efficacy is usually impacted by non-adherence due to difficult dosing and side-effects. Diazepam, a commonly prescribed benzodiazepine carries risks of CNS depression as well as addiction and abuse. Evidence supporting its use is mostly dated, but more recent findings support short-term use for pain control as well as enabling non-pharmacological interventions that achieve long term benefit but would otherwise not be tolerated. More recent options include cyclobenzaprine and tizanidine. Cyclobenzaprine carries a more significant adverse events profile, including CNS sedation; it was found to be effective, possible as effective as diazepam, however, it is not currently FDA approved for CP-related spasticity and further evidence is required to support its use. Tizanidine was shown to be very effective in a handful of small studies.

Summary: Muscle relaxants are an important adjunct in CP therapy and are crucial in treatment of pain, as well as enabling participation in other forms of treatments. Evidence exist to support their use, however, it is not without risk and further research is required to highlight proper dosing, co-treatments and patient selection.

Keywords: baclofen; cerebral palsy; chronic pain; cyclobenzaprine; dantrolene; diazepam; dystonia; spasticity; tizanadine.