Medicine & USMLE

Muscle Relaxants

Musculoskeletal Drugs
  1. Corticosteroids
  2. Acetaminophen
  3. Azathioprine
  4. Sulfasalazine
  5. TNF Inhibitors
  6. Immunosuppressants (Cyclosporine, Mycophenolate, Tacrolimus)
  7. NSAIDs
  8. Colchicine
  9. Allopurinol
  10. Rasburicase
  11. Dantrolene
  12. Muscle Relaxants
  13. Bisphosphonates: Alendronate, Risedronate


Muscle relaxants are a drug class that are used to treat muscle spasms associated with several skeletal muscle conditions like multiple sclerosis and cerebral palsy. Drugs to know in this class include baclofen, carisoprodol, methocarbamol, and cyclobenzaprine. Muscle relaxants can cause orthostatic hypotension and sedation, both of which are expected side effects. Patients taking muscle relaxants should avoid alcohol.

Key Points

  • Key Drugs
    • Baclofen (Lioresal)
    • Methocarbamol (Robaxin)
    • Carisoprodol (Soma)
    • Cyclobenzaprine (Flexeril)
    • Mechanism
      • Act on the brain/spinal cord to interfere with nerve pathways and decrease spasticity
    • Clinical Use
      • Muscle spasms
        • Spinal cord injuries
        • Cerebral palsy
        • Multiple sclerosis
        • Stroke
        • Post-surgery on open fractures
        • Tetanus
        • Intractable hiccups
    • Side Effects and Adverse Reactions
      • Orthostatic hypotension
        • An expected side effect
      • Sedation / Drowsiness
        • An expected side effect, and not a reason to stop taking the medication
        • Avoid alcohol
      • Dependence
        • Taper off medication, do not stop abruptly
        • Withdrawal symptoms include anxiety, restlessness, seizures, and hallucinations
      • Anticholinergic effects (cyclobenzaprine)
        • Constipation
          • Increase fluid and fiber intake
        • Contraindicated in glaucoma