Cyclobenzaprine Hydrochloride
Brand Names: Amrix, Flexeril, Fexmid
Generic tablets available in 5 mg and 10 mg.
Tablets (Flexeril): 5 mg and 10 mg.
Tablets (Flexmid): 7.5 mg.
Capsules, extended-release (Amrix): 15 mg and 30 mg.
Relief of skeletal muscle spasm associated with acute, painful musculoskeletal conditions: The recommended dose is 15 mg per day as 5 mg three times a day or one 15 mg extended-release capsule once per day. Based on individual patient response, the dose may be increased to 30 mg extended-release dose or 10 mg three times a day. Do not use for periods longer than 3 weeks, Do not use more than 60 mg per day.
Not recommended for children under 15 years of age.
Pharmacology/Pharmacokinetics:
Cyclobenzaprine does not act directly on skeletal muscle or at the neuromuscular synapses. It probably exerts its effect by acting at the brain stem in the CNS. The overall effect is a reduction of tonic somatic motor activity influencing both alpha and gamma motoneurons. Half-life can be as long as three days. Excretion of metabolized drug occurs via the kidneys.
Drug Interactions:
May enhance the effects of alcohol and other CNS depressants. May decrease the effects of guanethidine.
Contraindications/Precautions:
Contraindicated in patients with congestive heart failure, hyperthyroidism, cardiac arrhythmias, conductive disturbances, and during acute recovery phase of myocardial infarctions. Use with caution in patients with a history of urinary retention, closed-angle glaucoma, increased intraocular pressure, and also during pregnancy and lactation. Pregnancy Category B.
Adverse Effects:
Drowsiness, dizziness, dry mouth, fatigue, asthenia, nausea, constipation, dyspepsia, unpleasant taste, blurred vision, headache, nervousness, and confusion.
May cause drowsiness. Use caution while operating machinery or when mental alertness is required.
Avoid alcohol while taking this medication.
Store in a cool, dry place away from sunlight and children.
Contact a physician if the above side effects are severe or persistent.
If a dose is missed, skip it and return to normal dosing schedule.