Muscle relaxant drugs: An over view

Muscle relaxant drugs: An over view

Muscle relaxant drugs

These are the medicines that affect skeletal muscle function and decrease the muscle tone. It maybe used to alleviate symptoms such as spasm, pain and hyperreflexia. They usually administered together with anesthetics  during procedure or surgery.

They primary act as central nervous system depressants. Used in addition to rest, physical therapy, and other measures to relieve discomfort, muscle relaxants are beneficial for short term use for acute, painful muscle-skeletal conditions.

Muscle relaxants maybe classified into two groups; spasmolytics and neuromuscuar blockers. 

Spasmolytics are used to relieve skeletal muscle spasm and bring them from hypertonic state to normal tone.  

Neuromuscular blockers are drugs that completely paralyze skeletal muscles by interfering with acetylcholine at neuromuscular junction.


  • Baclofen

GABA-B Receptor agonist. It is indicated to alleviation of severe spasticity resulting from; mutiple sclerosis and patient with spinal cord injury. It is contraindicated  to hypotension patients and dyspnea when used with epidural morphine. It can be taken orally , when injected intrathecally effective CSF concentration can be achieved with result plasma concentrations 100 times less than with oral administration. side effects include dizziness, sedation and dry mouth.

  • Dantrolene

Interferes with the release of calcium from the sarcoplasmic reticulum through the SR calcium channel complex to produce  skeletal muscle relaxation. It is indicated to the immediately treatment of fulminant hypermetabolism of skeletal muscle characteristics of malignant hyperthermia. the drug may potentiate vecuronium-induced NMJ block. side effects include loss of grip strength and leg weakness, subjective CNS complaints from normal patients.

Acts on parts of the limbic system, the thalamus and hypothalamus to induce calming effect. 

indications: anxiety disorders, relief of skeletal muscle spasm, convulsive disorders, preoperative anxiety and initial treatment of status epileptic

contraindication: glaucoma, drug hypersensitivity,  

side effects include fatigue, drowsiness, ataxia, confusion.



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