Trade Names:Amrix- Capsules, extended-release 15 mg- Capsules, extended-release 30 mg
Trade Names:Cyclobenzaprine Hydrochloride- Tablets 7.5 mg
Trade Names:Flexeril- Tablets 5 mg- Tablets 10 mgApo-Cyclobenzaprine (Canada)Gen-Cyclobenzaprine (Canada)PMS-Cyclobenzaprine (Canada)ratio-Cyclobenzaprine (Canada)
Relieves skeletal muscle spasms of local origin without interfering with muscle function by acting within CNS at brain stem. Structurally and pharmacologically related to tricyclic antidepressants.
Mean oral bioavailability ranges from 33% to 55%. Reaches steady state in approximately 3 to 4 days following 3-times-daily dosing. C max is approximately 12.8 to 46.1 ng/mL and AUC is approximately 80 to 319 ng•h/mL.Extended-release (ER)
T max is 7 to 8 h. C max is 8 to 20 ng/mL. AUC is 354 to 780 ng•h/mL.
Highly bound to plasma proteins.
Extensively metabolized, primarily to glucuronide-like conjugates.
Excreted primarily via kidneys. The t ½ is approximately 8 to 37 h.ER
The t ½ is approximately 33 h.
12 to 24 h.
Relief of muscle spasms associated with acute painful musculoskeletal conditions.
Treatment of fibrositis.
Standard considerations; use of MAOIs or within 14 days of their discontinuation; acute recovery phase of MI; arrhythmias; heart block or conduction disturbances; CHF; hyperthyroidism.
5 to 10 mg 3 times daily.ER
15 to 30 mg once daily.
Store at 59° to 86°F.
May cause additive CNS depression.MAOIs
May cause hyperpyretic crisis, severe seizures, and death.
None well documented.
Palpitations (6%); arrhythmia, hypotension, syncope, tachycardia, vasodilation (postmarketing).
Somnolence (100%); drowsiness (39%); dizziness (19%); headache (17%); attention disturbance, tremor (6%); fatigue (3%); decreased mental acuity, irritability, nervousness (1% to 3%); abnormal sensations, abnormal thinking, agitation, anxiety, ataxia, depression, disorientation, dreaming, dysarthria, excitement, hallucinations, hypertonia, insomnia, malaise, paresthesia, psychosis, seizures, vertigo (postmarketing).
Acne (6%); sweating (postmarketing).
Dry throat (8%); blurred vision (3%); pharyngitis (1% to 3%); ageusia, diplopia, tinnitus (postmarketing).
Dry mouth (58%); nausea (8%); dysgeusia (6%); dyspepsia (4%); constipation (3%); abdominal pain, acid regurgitation, diarrhea (1% to 3%); anorexia, flatulence, gastritis, GI pain, thirst, tongue edema, vomiting (postmarketing).
Urinary frequency, urinary retention (postmarketing).
Abnormal liver function, cholestasis, hepatitis, jaundice (postmarketing).
Anaphylaxis (including angioedema), facial edema, pruritus, rash, urticaria (postmarketing).
Local weakness, muscle twitching (postmarketing); myalgia.
Category B .
Safety and efficacy in children younger than 15 yr of age not established.
Do not use ER in elderly patients.
Do not administer ER to patients with hepatic function impairment.
Use with caution in patients with angle-closure glaucoma, increased IOP, and urinary retention.
Agitation, arrhythmia, ataxia, cardiac arrest, cardiac dysrhythmias, chest pain, CHF, coma, confusion, dilated pupils, dizziness, drowsiness, ECG changes (particularly in QRS axis), hyperactive reflexes, hyperpyrexia, hypertension, hypotension, hypothermia, nausea, neuroleptic malignant syndrome, seizures, slurred speech, stupor, tachycardia, tremor, visual hallucinations, vomiting.
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