Psychiatric Drugs and Medications Q 46

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Peripherally acting skeletal muscle relaxants are used:

  

     A. To treat neuromuscular diseases

     B. To treat spinal trauma

     C. To relieve spasms from trauma

     D. As adjuncts to general anesthesia

    

    

Correct Answer: D. As adjuncts to general anesthesia

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Peripherally acting skeletal muscle relaxants are used as an adjunct to general anesthesia. Repeat doses can be given during anesthesia and surgery in prolonged cases. Although this is an approved indication for the use of dantrolene, it is an unnecessary use if patients avoid triggering agents when they are susceptible to malignant hyperthermia.

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Option A: Among the many indications for the use of dantrolene, its primary indication, and FDA approved usage in both children and adults, is for the treatment of malignant hyperthermia: the very rare, but life-threatening disorder triggered by general anesthesia.

Option B: Malignant hyperthermia is a reaction to the volatile halogenated anesthetics, or depolarizing muscle relaxants, causing sustained muscle contraction, hyperthermia, rhabdomyolysis, and hypercarbia, potentially leading to intraoperative patient demise. These symptoms develop as a response to the anesthetic agents acting on defective ryanodine receptors (calcium channels in muscle cell sarcoplasmic reticulum).

Option C: Other FDA-approved uses for dantrolene include muscle spasticity disorders, as seen with upper motor neuron disorders including stroke, spinal cord injury, cerebral palsy, and multiple sclerosis. It is the only FDA approved oral peripherally acting antispasmodic medication for these disorders.

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