Skeletal muscle relaxants are a diverse group of prescription medications used to relieve muscle spasm, cramping, and stiffness associated with musculoskeletal injuries (acute spasm) or neurological conditions such as multiple sclerosis and spinal cord injury (spasticity). They are broadly divided into two categories:
- Antispasmodics (for acute musculoskeletal spasm) — include cyclobenzaprine, methocarbamol, carisoprodol, and metaxalone. These act centrally (in the brain and spinal cord) to inhibit motor neurone activity. They are short-term treatments typically prescribed for 2–3 weeks alongside rest, physical therapy, and analgesics.
- Antispastics (for neurological spasticity) — include tizanidine, baclofen, and dantrolene. These reduce pathological spasm in conditions involving upper motor neurone lesions, such as spinal cord injury or MS.
None of the major skeletal muscle relaxants are available OTC in the US. All require a prescription. Sedation and CNS depression are important side effects across the class, and patients should avoid alcohol and driving while taking them.
Muscle Relaxants Available at Lucas Clinic
- Robaxin (Methocarbamol) — 500/750 mg tablets; central-acting antispasmodic for acute musculoskeletal spasm; TID/QID dosing
- Zanaflex (Tizanidine) — 2/4 mg tablets and capsules; alpha-2 agonist antispastic for spasticity in MS and spinal cord injury