Cyclobenzaprine

Brand names: AMRIX, Cyclobenzaprine Hydrochloride

Warnings

Warnings: Cyclobenzaprine is structurally related to tricyclic antidepressants and may produce serious CNS reactions at higher doses. The drug "may enhance the effects of alcohol, barbiturates, and other CNS depressants." Tricyclic antidepressants have been associated with arrhythmias, tachycardia, and conduction problems. Contraindications: Concomitant use with MAO inhibitors (within 14 days of discontinuation) is contraindicated due to risk of "hyperpyretic crisis seizures, and deaths." Also contraindicated in acute myocardial infarction recovery phase, arrhythmias, heart block, congestive heart failure, and hyperthyroidism. Special Populations: Elderly patients and those with hepatic impairment require dose reduction, starting with 5 mg and titrating slowly upward.

Contraindications

CONTRAINDICATIONS Hypersensitivity to any component of this product. Concomitant use of monoamine oxidase (MAO) inhibitors or within 14 days after their discontinuation. Hyperpyretic crisis seizures, and deaths have occurred in patients receiving cyclobenzaprine (or structurally similar tricyclic antidepressants) concomitantly with MAO inhibitor drugs. Acute recovery phase of myocardial infarction, and patients with arrhythmias, heart block or conduction disturbances, or congestive heart failure. Hyperthyroidism.

Overdose

OVERDOSAGE Although rare, deaths may occur from overdosage with cyclobenzaprine hydrochloride. Multiple drug ingestion (including alcohol) is common in deliberate cyclobenzaprine overdose. As management of overdose is complex and changing, it is recommended that the physician contact a poison control center for current information on treatment. Signs and symptoms of toxicity may develop rapidly after cyclobenzaprine overdose; therefore, hospital monitoring is required as soon as possible. The acute oral LD 50 of cyclobenzaprine hydrochloride is approximately 338 and 425 mg/kg in mice and rats, respectively. Manifestations The most common effects associated with cyclobenzaprine overdose are drowsiness and tachycardia. Less frequent manifestations include tremor, agitation, coma, ataxia, hypertension, slurred speech, confusion, dizziness, nausea, vomiting, and hallucinations. Rare but potentially critical manifestations of overdose are cardiac arrest, chest pain, cardiac dysrhythmias, severe hypotension, seizures, and neuroleptic malignant syndrome. Changes in the electrocardiogram, particularly in QRS axis or width, are clinically significant indicators of cyclobenzaprine toxicity. Other potential effects of overdosage include any of the symptoms listed under ADVERSE REACTIONS . Management General As management of overdose is complex and changing, it is recommended that the physician contact a poison control center for current information on treatment. In order to protect against the rare but potentially critical manifestations described above, obtain an ECG and immediately initiate cardiac monitoring. Protect the patient's airway, establish an intravenous line and initiate gastric decontamination. Observation with cardiac monitoring and observation for signs of CNS or respiratory depression, hypotension, cardiac dysrhythmias and/or conduction blocks, and seizures is necessary. If signs of toxicity occur at any time during this period, extended monitoring is required. Monitoring of plasma drug levels should not guide management of the patient. Dialysis is probably of no value because of low plasma concentrations of the drug. Gastrointestinal Decontamination All patients suspected of an overdose with cyclobenzaprine hydrochloride should receive gastrointestinal decontamination. This should include large volume gastric lavage followed by activated charcoal. If consciousness is impaired, the airway should be secured prior to lavage and emesis is contraindicated. Cardiovascular A maximal limb-lead QRS duration of ≥0.10 seconds may be the best indication of the severity of the overdose. Serum alkalinization, to a pH of 7.45 to 7.55, using intravenous sodium bicarbonate and hyperventilation (as needed), should be instituted for patients with dysrhythmias and/or QRS widening. A pH >7.60 or a pCO 2 <20 mmHg is undesirable. Dysrhythmias unresponsive to sodium bicarbonate therapy/hyperventilation may respond to lidocaine, bretylium or phenytoin. Type 1A and 1C antiarrhythmics are generally contraindicated (e.g., quinidine, disopyramide, and procainamide). CNS In patients with CNS depression, early intubation is advised because of the potential for abrupt deterioration. Seizures should be controlled with benzodiazepines or, if these are ineffective, other anticonvulsants (e.g. phenobarbital, phenytoin). Physostigmine is not recommended except to treat life-threatening symptoms that have been unresponsive to other therapies, and then only in close consultation with a poison control center. Psychiatric Follow-up Since overdosage is often deliberate, patients may attempt suicide by other means during the recovery phase. Psychiatric referral may be appropriate. Pediatric management The principles of management of child and adult overdosages are similar. It is strongly recommended that the physician contact the local poison control center for specific pediatric treatment.

Drug interactions

Drug Interactions Cyclobenzaprine may have life threatening interactions with MAO inhibitors. (See CONTRAINDICATIONS .) Postmarketing cases of serotonin syndrome have been reported during combined use of Cyclobenzaprine Hydrochloride and other drugs, such as SSRIs, SNRIs, TCAs, tramadol, bupropion, meperidine, verapamil, or MAO inhibitors. If concomitant treatment with Cyclobenzaprine Hydrochloride and other serotonergic drugs is clinically warranted, careful observation is advised, particularly during treatment initiation or dose increases (see WARNINGS ). Cyclobenzaprine hydrochloride may enhance the effects of alcohol, barbiturates, and other CNS depressants. Tricyclic antidepressants may block the antihypertensive action of guanethidine and similarly acting compounds. Tricyclic antidepressants may enhance the seizure risk in patients taking tramadol. † † ULTRAM ® (tramadol hydrochloride tablets, Ortho-McNeil Pharmaceutical) † ULTRACET ® (tramadol hydrochloride and acetaminophen tablets, Ortho-McNeil Pharmaceutical)

Uses

"Cyclobenzaprine HCl tablets are indicated as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute, painful musculoskeletal conditions." The medication should be used only for short periods (up to two or three weeks). It has not proven effective for spasticity related to cerebral or spinal cord disease, or in children with cerebral palsy.

Dosage forms & strengths

Capsule, Extended Release Tablet, Coated Tablet, Film Coated TABLET, FILM COATED TABLET POWDER

CYCLOBENZAPRINE HYDROCHLORIDE 10 mg CYCLOBENZAPRINE HYDROCHLORIDE 15 mg CYCLOBENZAPRINE HYDROCHLORIDE 30 mg CYCLOBENZAPRINE HYDROCHLORIDE 5 mg CYCLOBENZAPRINE HYDROCHLORIDE 7.5 mg Cyclobenzaprine Hydrochloride 10 mg Cyclobenzaprine Hydrochloride 5 mg CYCLOBENZAPRINE HYDROCHLORIDE 10 mg/1 CYCLOBENZAPRINE HYDROCHLORIDE 5 mg/1 CYCLOBENZAPRINE HYDROCHLORIDE 1 kg/kg

DOSAGE AND ADMINISTRATION For most patients, the recommended dose of cyclobenzaprine hydrochloride tablets USP is 5 mg three times a day. Based on individual patient response, the dose may be increased to 10 mg three times a day. Use of cyclobenzaprine hydrochloride tablets USP for periods longer than two or three weeks is not recommended. (see INDICATIONS AND USAGE ). Less frequent dosing should be considered for hepatically impaired or elderly patients (see PRECAUTIONS , Impaired Hepatic Function , and Use in the Elderly ).