Cyclobenzaprine (Flexeril)

Action: acts within CNS at brainstem level. Net effect is reduction of tonic somatic motor activity influencing motor neurons to muscle. Less firing of alpha motor neurons; does not paralyze muscles, only relieves spasm. These drugs (including Diazepam and Baclofen) are NOT skeletal muscle blocking drugs.

Use: to relieve skeletal muscle spasm of local origin. Does not paralyze muscle. Effective orally.

Precautions: because of atropine-like side effects, should be used with caution in patients with urinary retention, glaucoma (increased intraocular pressure)… glaucoma can be exacerbated by any anticholinergic drug.

Side Effects: Drowsiness (16%), dry mouth (7%), dizziness (3%).

Flexeril is popular among internists for managing pain, although it doesn’t cure anything.

Category: Pharmacology Notes