Medicine & USMLE


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


Dantrolene is a muscle relaxant that is also used to treat malignant hyperthermia and neuroleptic malignant syndrome or NMS. Side effects of dantrolene include hepatotoxicity, so carefully watch the liver enzymes and teach the patient to avoid alcohol. Dantrolene can also cause sedation as an expected side effect.

Key Points

  • Mechanism
    • Muscle relaxant
      • Directly targets the muscle fibers, causing them to relax
    • Clinical Uses
      • Malignant hyperthermia
        • A rare, but life threatening condition where the body is triggered (usually by anesthetics) to release an excess amount of calcium, causing sustained muscle contraction
        • Usually in response to inhaled anesthetics or succinylcholine
      • Muscle spasms
        • Associated with cerebral palsy, spinal cord injuries, and multiple sclerosis
      • Neuroleptic malignant syndrome (NMS)
        • Rare side effect of antipsychotics (neuroleptic) medications, manifesting as lead pipe muscle rigidity, hyperthermia, and altered mentation
    • Side Effects and Adverse Reactions
      • Hepatotoxicity
        • Black box warning
        • Contraindicated with cirrhosis and liver failure
        • Monitor liver function tests
        • Avoid alcohol
      • Sedation / Drowsiness