AMRIX Cyclobenzaprine Hydrochloride 30 mg Capsule, Extended Release, 60-count
Other active recalls for Cyclobenzaprine Hydrochloride (different manufacturers) — 1 · tap to view
🆔 Identity & classification
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🏭 Manufacturer & labeler
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🩺 Clinical
Cyclobenzaprine is used to treat muscle spasms. Cyclobenzaprine is in a class of medications called skeletal muscle relaxants. It works by acting in the brain and nervous system to allow the muscles to relax.
Read the full MedlinePlus article ↗- It's a muscle relaxant prescribed to help ease muscle spasms, pain, and stiffness from acute musculoskeletal injuries — like a back strain or a pulled muscle. It's meant to be used...
- What is cyclobenzaprine actually used for?
- Yes, drowsiness is one of the most common side effects — it's real and can be significant. You should not drive, operate heavy machinery, or do anything that requires sharp focus u...
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
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Diethyl phthalate is a clear, colorless liquid made from phthalic acid. It's used in medicines as a plasticizer to make tablet coatings flexible and as a solvent to help dissolve and distribute active ingredients evenly throughout the product.
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Ethylcellulose is a plant-fiber derivative used as a binder and film-coating agent in tablets and capsules. It helps hold ingredients together and can create a protective coating that controls how quickly the medicine dissolves.
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FD&C Blue No. 1 is a synthetic blue dye approved for use in foods and medicines. It serves as a colorant to give the medication its distinctive appearance and help with product identification.
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A synthetic blue dye approved by the FDA for use in medications and foods. It serves as a colorant to make pills and liquids visually distinct and easier to identify.
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A synthetic red dye used to color medications and make them easier to identify. It serves as a colorant in tablets, capsules, and liquid formulations.
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A synthetic yellow dye used to color medications. It helps identify the drug and make it visually distinctive, with no effect on how the medicine works.
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Gelatin is a protein derived from animal collagen, commonly used in medicines as a gelling agent and capsule material. It helps create soft or hard capsule shells that hold and release medication, and can also thicken liquid formulations.
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Hypromellose 2910 is a plant-based cellulose derivative that acts as a thickener, binder, and film-coating agent. It helps control how quickly the medicine dissolves and protects the tablet or capsule from moisture and light.
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Polyethylene glycol 400 is a clear, thick liquid made from petroleum-derived polymers. It acts as a solvent and humectant in medicines, helping dissolve active ingredients and retain moisture in the formulation.
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Polyethylene glycol 8000 is a synthetic polymer made from ethylene oxide. It acts as a binder and filler in tablets and capsules, helping hold ingredients together and add bulk to the medicine.
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A plant-based carbohydrate derived from corn kernels. It acts as a filler to add bulk, a binder to hold ingredients together, and a disintegrant to help the tablet break apart in your stomach for absorption.
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A natural sugar derived from sugar cane or sugar beets. It's used as a sweetener, filler, and binder to improve taste, add bulk, and help hold tablet or capsule ingredients together.
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Titanium dioxide is a bright white mineral powder commonly used as a colorant and opacifying agent. It makes pills and tablets white or lighter in color and helps make coatings non-transparent.
13 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $66.567 | $3,994.03 / 60 capsules |
| Medicaid paysCMS SDUD · 12 mo | No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data. | |
| Medicare drug plans payPart D · Q2 2026 | $66.70 | $4,001.77 / 60 capsules |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Cyclobenzaprine Hydrochloride 30 mg 00093-1921-06 | Teva | 60 capsules | $0.893 | AB | Availability likely | save 99% |
| Cyclobenzaprine Hydrochloride 30 mg 00115-1437-13 | Amneal | 60 capsules | $0.893 | AB | Availability likely | save 99% |
| Cyclobenzaprine Hydrochloride 30 mg 24979-0036-04 | Upsher-Smith | 60 capsules | $0.893 | AB | Availability likely | save 99% |
| Amrix 30 mgthis 63459-0701-60 | Cephalon, | 60 capsules | $66.567 | AB | Availability likely | — |
| Cyclobenzaprine Hydrochloride 30 mg 33342-0273-09 | Macleods | 60 capsules | — | AB | FDA listed | — |
| Cyclobenzaprine Hydrochloride 30 mg 70518-4174-00 | REMEDYREPACK | 30 capsules | — | AB | FDA listed | — |
| Cyclobenzaprine Hydrochloride 30 mg 70518-4523-00 | REMEDYREPACK | 30 capsules | — | AB | FDA listed | — |
| Cyclobenzaprine Hydrochloride 30 mg 71205-0858-00 | Proficient | 100 capsules | — | AB | FDA listed | — |
| Cyclobenzaprine Hydrochloride 30 mg 71335-2696-01 | Bryant | 30 capsules | — | AB | FDA listed | — |
| Cyclobenzaprine Hydrochloride 30 mg 76420-0896-01 | Asclemed | 100 capsules | — | AB | FDA listed | — |
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⏳ Availability & generic status
FDA-approved generic versions are listed, and recent pricing/market data suggests they may be available — see Therapeutic equivalents.
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📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 63459-0701-60 You're viewing this | 60 CAPSULE, EXTENDED RELEASE in 1 BOTTLE (63459-701-60) | 2007-11-01 | Active |
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE AMRIX ® (cyclobenzaprine hydrochloride extended-release capsules) is indicated as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute, painful musculoskeletal conditions. Improvement is manifested by relief of muscle spasm and its associated signs and symptoms, namely, pain, tenderness, and limitation of motion. Limitations of Use: AMRIX should be used only for short periods (up to two or three weeks) because adequate evidence of effectiveness for more prolonged use is not available and because muscle spasm associated with acute, painful musculoskeletal conditions is generally of short duration and specific therapy for longer periods is seldom warranted.
AMRIX has not been found effective in the treatment of spasticity associated with cerebral or spinal cord disease or in children with cerebral palsy. AMRIX is a muscle relaxant indicated as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute, painful musculoskeletal conditions. Improvement is manifested by relief of muscle spasm and its associated signs and symptoms, namely, pain, tenderness, and limitation of motion.
( 1 ) Limitations of Use: AMRIX should be used only for short periods (up to 2 or 3 weeks) because adequate evidence of effectiveness for more prolonged use is not available and because muscle spasm associated with acute, painful musculoskeletal conditions is generally of short duration and specific therapy for longer periods is seldom warranted. ( 1 ) AMRIX has not been found effective in the treatment of spasticity associated with cerebral or spinal cord disease or in children with cerebral palsy. (1)
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION The recommended adult dose for most patients is one (1) AMRIX 15 mg capsule taken once daily. Some patients may require up to 30 mg/day, given as one (1) AMRIX 30 mg capsule taken once daily or as two (2) AMRIX 15 mg capsules taken once daily. It is recommended that doses be taken at approximately the same time each day.
Use of AMRIX for periods longer than two or three weeks is not recommended [ see Indications and Usage (1) ]. Instruct patients to swallow AMRIX capsules intact. Alternatively, the contents of the AMRIX capsule may be sprinkled over applesauce and then swallowed.
This method is appropriate only for patients able to reliably swallow the applesauce without chewing. Other foods have not been tested and should not be substituted for applesauce. Instruct the patient to: Sprinkle the contents of the capsule onto a tablespoon of applesauce and consume immediately without chewing.
Rinse the mouth to ensure all of the contents have been swallowed. Discard any unused portion of the AMRIX capsules after the contents have been sprinkled on applesauce. Recommended adult dose for most patients is 15 mg taken once daily.
Some patients may require 30 mg taken once daily (2) Recommended to take doses at approximately same time each day (2) Instruct patients to swallow AMRIX capsules intact or to sprinkle capsule contents on a tablespoon of applesauce and swallow immediately without chewing ( 2 ) Use for periods longer than 2 or 3 weeks is not recommended (2)
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS Extended-release capsules in the following strengths: 15 mg: Capsules are orange/orange and are embossed in blue ink with “15 mg” on the body, and Cephalon “C” logo, “Cephalon,” and a dashed band on the cap. 30 mg: Capsules are blue/red and are embossed in white ink with “30 mg” on the body, and Cephalon “C” logo, “Cephalon,” and a dashed band on the cap. Extended-release capsules: 15 and 30 mg (3)
⛔ Contraindications ▾
4 CONTRAINDICATIONS Hypersensitivity to any component of this product. Adverse reactions may include anaphylactic reaction, urticaria, facial and/or tongue swelling, or pruritus. Discontinue AMRIX if a hypersensitivity reaction is suspected.
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. During the acute recovery phase of myocardial infarction, and in patients with arrhythmias, heart block or conduction disturbances, or congestive heart failure.
Hyperthyroidism. Hypersensitivity to any component of this product (4) Concomitant use of monoamine oxidase (MAO) inhibitors or within 14 days after their discontinuation (4) During acute recovery phase of myocardial infarction, and in patients with arrhythmias, heart block or conduction disturbances, or congestive heart failure (4) Hyperthyroidism (4)
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS Serotonin syndrome has been reported with cyclobenzaprine when used in combination with other serotonergic drugs ( 5.1 ) Cyclobenzaprine is structurally related to tricyclic antidepressants which have been reported to produce adverse cardiovascular effects or CNS depressant effects ( 5.2 ) Use in the elderly is not recommended ( 5.3 ) Use in patients with hepatic impairment is not recommended ( 5.4 ) Use with caution in patients with a history of urinary retention, angle-closure glaucoma, increased intraocular pressure and in patients taking anticholinergic medications ( 5.5 )
5.1Serotonin Syndrome The development of a potentially life-threatening serotonin syndrome has been reported with cyclobenzaprine when used in combination with other drugs, such as selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), tramadol, bupropion, meperidine, verapamil, or MAO inhibitors. The concomitant use of AMRIX with MAO inhibitors is contraindicated [see Contraindications (4)] . Serotonin syndrome symptoms may include mental status changes (e.g., confusion, agitation, hallucinations), autonomic instability (e.g., diaphoresis, tachycardia, labile blood pressure, hyperthermia), neuromuscular abnormalities (e.g., tremor, ataxia, hyperreflexia, clonus, muscle rigidity), and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).
Treatment with AMRIX and any concomitant serotonergic agents should be discontinued immediately if the above reactions occur and supportive symptomatic treatment should be initiated. If concomitant treatment with AMRIX and other serotonergic drugs is clinically warranted, careful observation is advised, particularly during treatment initiation or dose increases.
5.2Tricyclic Antidepressant-like Effects Cyclobenzaprine is structurally related to the tricyclic antidepressants, e.g., amitriptyline and imipramine. Tricyclic antidepressants have been reported to produce arrhythmias, sinus tachycardia, prolongation of the conduction time leading to myocardial infarction and stroke [see Contraindications (4)] . AMRIX may enhance the effects of alcohol, barbiturates, and other CNS depressants.
Some of the more serious central nervous system (CNS) reactions noted with the tricyclic antidepressants have occurred in short-term studies of cyclobenzaprine for indications other than muscle spasm associated with acute musculoskeletal conditions, and usually at doses somewhat greater than those recommended for skeletal muscle spasm. If clinically significant CNS symptoms develop, consider discontinuation of AMRIX.
5.3Use in the Elderly As a result of a 40% increase in cyclobenzaprine plasma levels and a 56% increase in plasma half-life following administration of AMRIX in elderly subjects as compared to young adults, use of AMRIX is not recommended in the elderly [ see Clinical Pharmacology (12.3) ].
5.4Use in Patients with Hepatic Impairment As a result of two-fold higher cyclobenzaprine plasma levels in subjects with mild hepatic impairment, as compared to healthy subjects, following administration of immediate-release cyclobenzaprine and because there is limited dosing flexibility with AMRIX, use of AMRIX is not recommended in patients with mild, moderate, or severe hepatic impairment [ see Clinical Pharmacology (12.3) ].
5.5Atropine-like Action Because of its atropine-like action, AMRIX should be used with caution in patients with a history of urinary retention, angle-closure glaucoma, increased intraocular pressure, and in patients taking anticholinergic medication.
5.5Atropine-like Action Because of its atropine-like action, AMRIX should be used with caution in patients with a history of urinary retention, angle-closure glaucoma, increased intraocular pressure, and in patients taking anticholinergic medication.
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following clinically significant reactions are described in greater detail, in other sections. Serotonin Syndrome [see Warnings and Precautions ( 5.1 )] Adverse Cardiovascular Effects [see Warnings and Precautions ( 5.2 )] Most common adverse reactions (incidence ≥3% in any treatment group and greater than placebo): dry mouth, dizziness, fatigue, constipation, nausea, dyspepsia, and somnolence ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Teva Pharmaceuticals at 1-888-483-8279 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .
6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The data described below reflect exposure to AMRIX in 253 patients in 2 clinical trials. AMRIX was studied in two double-blind, parallel-group, placebo-controlled, active-controlled trials of identical design [see Clinical Studies (14)] .
The study population was composed of patients with muscle spasms associated with acute painful musculoskeletal conditions. Patients received 15 mg or 30 mg of AMRIX taken orally once daily, cyclobenzaprine immediate-release (IR) 10 mg three times a day, or placebo for 14 days. The most common adverse reactions (incidence ≥3% in any treatment group and greater than placebo) were dry mouth, dizziness, fatigue, constipation, nausea, dyspepsia, and somnolence (see Table 1).
Table 1: Incidence of the Most Common Adverse Reactions Occurring in ≥ 3% of Patients in any Treatment Group* and Greater Than Placebo in the Two Phase 3, Double-Blind AMRIX Trials Placebo AMRIX 15 mg AMRIX 30 mg N=128 N=127 N=126 Dry mouth 2% 6% 14% Dizziness 2% 3% 6% Fatigue 2% 3% 3% Constipation 0% 1% 3% Somnolence 0% 1% 2% Nausea 1% 3% 3% Dyspepsia 1% 0% 4% *AMRIX 15 mg QD, AMRIX 30 mg QD, or cyclobenzaprine IR tablets TID
6.2Postmarketing Experience The following adverse reactions have been reported in clinical studies or postmarketing experience with AMRIX, cyclobenzaprine IR, or tricyclic drugs. Because some of these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. In a postmarketing surveillance program of cyclobenzaprine IR, the adverse reactions reported most frequently were drowsiness, dry mouth, and dizziness and adverse reactions reported in 1% to 3% of the patients were: fatigue/tiredness, asthenia, nausea, constipation, dyspepsia, unpleasant taste, blurred vision, headache, nervousness, and confusion.
The following adverse reactions have been reported in postmarketing experience (AMRIX or cyclobenzaprine IR), in clinical studies of cyclobenzaprine IR (incidence <1%), or in postmarketing experience with other tricyclic drugs: Body as a Whole: Syncope; malaise; chest pain; edema. Cardiovascular: Tachycardia; arrhythmia; vasodilatation; palpitation; hypotension; hypertension; myocardial infarction; heart block; stroke. Digestive: Vomiting; anorexia; diarrhea; gastrointestinal pain; gastritis; thirst; flatulence; edema of the tongue; abnormal liver function and rare reports of hepatitis, jaundice, and cholestasis; paralytic ileus, tongue discoloration; stomatitis; parotid swelling.
Endocrine: Inappropriate ADH syndrome. Hematologic and Lymphatic: Purpura; bone marrow depression; leukopenia; eosinophilia; thrombocytopenia. Hypersensitivity: Anaphylaxis; angioedema; pruritus; facial edema; urticaria; rash.
Metabolic, Nutritional, and Immune: Elevation and lowering of blood sugar levels; weight gain or loss. Musculoskeletal: Local weakness; myalgia. Nervous System and Psychiatric: Seizures; ataxia; vertigo; dysarthria; tremors; hypertonia; convulsions; muscle twitching; disorientation; insomnia; depressed mood; abnormal sensations…
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS Based on its structural similarity to tricyclic antidepressants, AMRIX may have life-threatening interactions with MAO inhibitors [ see Contraindications (4) ] , may enhance the effects of alcohol, barbiturates, and other CNS depressants, may enhance the seizure risk in patients taking tramadol, or may block the antihypertensive action of guanethidine and similarly acting compounds. Postmarketing cases of serotonin syndrome have been reported during combined use of cyclobenzaprine and other drugs, such as SSRIs, SNRIs, TCAs, tramadol, bupropion, meperidine, verapamil, or MAO inhibitors [see Warnings and Precautions (5.1)] .
MAO Inhibitors: Life-threatening interactions may occur ( 4 , 7 ) Serotonergic Drugs: Serotonin syndrome has been reported ( 5.1 , 7 ) CNS Depressants: Effects of alcohol, barbiturates, and other CNS depressants may be enhanced ( 5.2 , 7 ) Tramadol: Seizure risk may be enhanced ( 7 ) Guanethidine: Antihypertensive effect may be blocked ( 7 )
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS
8.1Pregnancy Risk Summary Available data from case reports with AMRIX use in pregnancy have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In rats, decreased pup body weight and survival was noted at cyclobenzaprine doses ≥10 mg/kg/day (approximately ≥3 times the maximum recommended human dose (MRHD) of 30 mg/day), when administered orally during pregnancy and lactation (see Data). The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown.
All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data No adverse embryofetal effects were reported following oral administration of cyclobenzaprine during organogenesis to mice and rabbits at maternal doses up to 20 mg/kg/day (approximately 3 and 15 times the MRHD, respectively, on a mg/m 2 basis).
Maternal toxicity characterized by decreased body weight gain was observed only in mice at the highest tested dose of 20 mg/kg/day. Decreased pup body weight and survival were reported in a prenatal and postnatal study where pregnant rats were treated orally with cyclobenzaprine during pregnancy and lactation with maternal doses of 10 and 20 mg/kg/day (approximately 3 and 6 times the MRHD on a mg/m 2 basis). Maternal toxicity, characterized by a decreased body weight gain, was observed only at the highest tested dose of 20 mg/kg/day.
8.2Lactation Risk Summary There are no data on the presence of cyclobenzaprine in either human or animal milk, the effects on a breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for AMRIX and any potential adverse effects on the breastfed child from AMRIX or from the underlying maternal condition.
8.4Pediatric Use Safety and effectiveness of AMRIX have not been studied in pediatric patients.
8.5Geriatric Use Clinical studies of AMRIX did not include sufficient numbers of patients aged 65 and over to determine the safety and efficacy of AMRIX in the elderly population. The plasma concentration and half-life of cyclobenzaprine are substantially increased in the elderly when compared to the general patient population. Accordingly, use of AMRIX is not recommended in the elderly [see Warnings and Precautions (5.3) and Clinical Pharmacology (12.3)] .
8.6Hepatic Impairment The use of AMRIX is not recommended in patients with mild, moderate, or severe hepatic impairment [ see Warnings and Precautions (5.4 ) and Clinical Pharmacology ( 12.3 )].
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary Available data from case reports with AMRIX use in pregnancy have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In rats, decreased pup body weight and survival was noted at cyclobenzaprine doses ≥10 mg/kg/day (approximately ≥3 times the maximum recommended human dose (MRHD) of 30 mg/day), when administered orally during pregnancy and lactation (see Data). The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown.
All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data No adverse embryofetal effects were reported following oral administration of cyclobenzaprine during organogenesis to mice and rabbits at maternal doses up to 20 mg/kg/day (approximately 3 and 15 times the MRHD, respectively, on a mg/m 2 basis).
Maternal toxicity characterized by decreased body weight gain was observed only in mice at the highest tested dose of 20 mg/kg/day. Decreased pup body weight and survival were reported in a prenatal and postnatal study where pregnant rats were treated orally with cyclobenzaprine during pregnancy and lactation with maternal doses of 10 and 20 mg/kg/day (approximately 3 and 6 times the MRHD on a mg/m 2 basis). Maternal toxicity, characterized by a decreased body weight gain, was observed only at the highest tested dose of 20 mg/kg/day.
🧒 Pediatric Use ▾
8.4Pediatric Use Safety and effectiveness of AMRIX have not been studied in pediatric patients.
🧓 Geriatric Use ▾
8.5Geriatric Use Clinical studies of AMRIX did not include sufficient numbers of patients aged 65 and over to determine the safety and efficacy of AMRIX in the elderly population. The plasma concentration and half-life of cyclobenzaprine are substantially increased in the elderly when compared to the general patient population. Accordingly, use of AMRIX is not recommended in the elderly [see Warnings and Precautions (5.3) and Clinical Pharmacology (12.3)] .
🆘 Overdosage ▾
10 OVERDOSAGE Clinical Presentation Although rare, deaths may occur from overdosage with AMRIX. 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 most common effects associated with cyclobenzaprine overdose are drowsiness and tachycardia. Less frequent symptoms include tremor, agitation, coma, ataxia, hypertension, slurred speech, confusion, dizziness, nausea, vomiting, and hallucinations.
Rare but potentially critical symptoms of overdose are cardiac arrest, chest pain, cardiac dysrhythmias, severe hypotension, seizures, cases of neuroleptic malignant syndrome and rhabdomyolysis have been reported. 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 ( 6 ) .
Treatment of Overdose 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 symptoms 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 AMRIX 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 overdosage are similar.
It is strongly recommended that the physician contact the local poison control center for specific pediatric treatment.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action Cyclobenzaprine relieves skeletal muscle spasm of local origin without interfering with muscle function. Cyclobenzaprine has not been shown to be effective in muscle spasm due to central nervous system disease. In animal models, cyclobenzaprine reduced or abolished skeletal muscle hyperactivity.
Animal studies indicate that cyclobenzaprine does not act at the neuromuscular junction or directly on skeletal muscle. Such studies show that cyclobenzaprine acts primarily within the central nervous system at the brain stem as opposed to the spinal cord level, although an overlapping action on the latter may contribute to its overall skeletal muscle relaxant activity. Evidence suggests that the net effect of cyclobenzaprine is a reduction of tonic somatic motor activity, influencing both gamma (γ) and alpha (α) motor systems.
Pharmacological studies in animals demonstrated a similarity between the effects of cyclobenzaprine and the structurally related tricyclic antidepressants, including reserpine antagonism, norepinephrine potentiation, potent peripheral and central anticholinergic effects, and sedation. Cyclobenzaprine caused slight to moderate increase in heart rate in animals.
12.3Pharmacokinetics Absorption Following single-dose administration of AMRIX 15 mg and 30 mg in healthy adult subjects (n=15) , C max, AUC 0-168h and AUC 0-∞ increased in an approximately dose-proportional manner from 15 mg to 30 mg. The time to peak plasma cyclobenzaprine concentration (T max ) was 7 to 8 hours for both doses of AMRIX. A food effect study conducted in healthy adult subjects (n=15) utilizing a single dose of AMRIX 30 mg demonstrated a statistically significant increase in bioavailability when AMRIX 30 mg was given with food relative to the fasted state.
There was a 35% increase in peak plasma cyclobenzaprine concentration (C max ) and a 20% increase in exposure (AUC 0-168h and AUC 0-∞ ) in the presence of food. No effect, however, was noted in T max or the shape of the mean plasma cyclobenzaprine concentration versus time profile. Cyclobenzaprine in plasma was first detectable in both the fed and fasted states at 1.5 hours.
When the contents of AMRIX capsules were administered by sprinkling on applesauce, it was found to be bioequivalent to the same dose when administered as an intact capsule. In a multiple-dose study utilizing AMRIX 30 mg administered once daily for 7 days in a group of healthy adult subjects (n=35), a 2.5-fold accumulation of plasma cyclobenzaprine levels was noted at steady-state. Metabolism and Excretion Cyclobenzaprine is extensively metabolized and is excreted primarily as glucuronides via the kidney.
Cytochromes P-450 3A4, 1A2, and, to a lesser extent, 2D6, mediate N-demethylation, one of the oxidative pathways for cyclobenzaprine. Cyclobenzaprine has an elimination half-life of 32 hours (range 8-37 hours; n=18); plasma clearance is
0.7L/min following single-dose administration of AMRIX. Special Populations Elderly Although there were no notable differences in C max or T max , cyclobenzaprine plasma AUC is increased by 40% and the plasma half-life of cyclobenzaprine is prolonged in elderly subjects greater than 65 years of age (50 hours) after dosing with AMRIX compared to younger subjects 18 to 45 years of age (32 hours). Pharmacokinetic characteristics of cyclobenzaprine following multiple-dose administration of AMRIX in the elderly were not evaluated.
Hepatic Impairment In a pharmacokinetic study of immediate-release cyclobenzaprine in 16 subjects with hepatic impairment (15 mild, 1 moderate per Child-Pugh score), both AUC and C max were approximately double the values seen in the healthy control group. The pharmacokinetics of cyclobenzaprine in subjects with severe hepatic impairment is not known.
🧬 Mechanism of Action ▾
12.1Mechanism of Action Cyclobenzaprine relieves skeletal muscle spasm of local origin without interfering with muscle function. Cyclobenzaprine has not been shown to be effective in muscle spasm due to central nervous system disease. In animal models, cyclobenzaprine reduced or abolished skeletal muscle hyperactivity.
Animal studies indicate that cyclobenzaprine does not act at the neuromuscular junction or directly on skeletal muscle. Such studies show that cyclobenzaprine acts primarily within the central nervous system at the brain stem as opposed to the spinal cord level, although an overlapping action on the latter may contribute to its overall skeletal muscle relaxant activity. Evidence suggests that the net effect of cyclobenzaprine is a reduction of tonic somatic motor activity, influencing both gamma (γ) and alpha (α) motor systems.
Pharmacological studies in animals demonstrated a similarity between the effects of cyclobenzaprine and the structurally related tricyclic antidepressants, including reserpine antagonism, norepinephrine potentiation, potent peripheral and central anticholinergic effects, and sedation. Cyclobenzaprine caused slight to moderate increase in heart rate in animals.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING
16.1How Supplied AMRIX extended-release capsules are available in 15 and 30 mg strengths, packaged in bottles of 60 capsules. AMRIX 15 mg capsules (NDC 63459-700-60) are orange/orange and are embossed in blue ink with “15 mg” on the body, and Cephalon “C” logo, “Cephalon”, and a dashed band on the cap. AMRIX 30 mg capsules (NDC 63459-701-60) are blue/red and are embossed in white ink with “30 mg” on the body, and Cephalon “C” logo, “Cephalon”, and a dashed band on the cap.
16.2Storage and Handling Dispense in a tight, light-resistant container as defined in the USP/NF. Store at 25°C (77°F); excursions permitted to 15 - 30°C (59 - 86°F) [see USP Controlled Room Temperature].
16.1How Supplied AMRIX extended-release capsules are available in 15 and 30 mg strengths, packaged in bottles of 60 capsules. AMRIX 15 mg capsules (NDC 63459-700-60) are orange/orange and are embossed in blue ink with “15 mg” on the body, and Cephalon “C” logo, “Cephalon”, and a dashed band on the cap. AMRIX 30 mg capsules (NDC 63459-701-60) are blue/red and are embossed in white ink with “30 mg” on the body, and Cephalon “C” logo, “Cephalon”, and a dashed band on the cap.
📦 Storage and Handling ▾
16.2Storage and Handling Dispense in a tight, light-resistant container as defined in the USP/NF. Store at 25°C (77°F); excursions permitted to 15 - 30°C (59 - 86°F) [see USP Controlled Room Temperature].
📋 Description ▾
11 DESCRIPTION AMRIX is a skeletal muscle relaxant which relieves muscle spasm of local origin without interfering with muscle function. The active ingredient in AMRIX extended-release capsules is cyclobenzaprine hydrochloride, USP. Cyclobenzaprine hydrochloride (HCl) is a white, crystalline tricyclic amine salt with the empirical formula C 20 H 21 N·HCl and a molecular weight of 311.9.
It has a melting point of 217°C, and a pK a of 8.47 at 25°C. It is freely soluble in water and alcohol, sparingly soluble in isopropanol, and insoluble in hydrocarbon solvents. If aqueous solutions are made alkaline, the free base separates.
Cyclobenzaprine HCl is designated chemically as 3-( 5H -dibenzo[ a,d ] cyclohepten-5-ylidene)- N,N -dimethyl-1-propanamine hydrochloride, and has the following structural formula: AMRIX extended-release capsules for oral administration are supplied in 15 and 30 mg strengths. AMRIX capsules contain the following inactive ingredients: diethyl phthalate NF, ethylcellulose NF (Ethocel Standard 10 Premium), gelatin, Opadry ® Clear YS-1-7006, sugar spheres NF (20-25 mesh), and titanium dioxide. AMRIX 15 mg capsules also contain D&C yellow #10, FD&C green #3, and FD&C red #40.
AMRIX 30 mg capsules also contain FD&C blue #1, FD&C blue #2, FD&C red #40, and FD&C yellow #6. Structural Formula
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION See FDA-approved patient labeling (Patient Information). Instruct patients to swallow AMRIX capsules intact or to sprinkle capsule contents on a tablespoon of applesauce and swallow immediately without chewing. Advise patients to stop taking AMRIX and to notify their physician right away if they experience symptoms of an allergic reaction, such as difficulty breathing, hives, swelling of face or tongue, or itching.
Advise patients that AMRIX should not be taken with MAO inhibitors or within 14 days after their discontinuation. Caution patients about the risk of serotonin syndrome with concomitant use of AMRIX and other drugs, such as SSRIs, SNRIs, TCAs, tramadol, bupropion, meperidine, verapamil, or MAO inhibitors. Advise patients of the signs and symptoms of serotonin syndrome [ see Warnings and Precautions (5.1) ] and instruct patients to seek medical care immediately if they experience these symptoms.
Advise patients to stop taking AMRIX and to notify their physician right away if they experience arrhythmias or tachycardia. Advise patients that AMRIX may enhance the impairment effects of alcohol. These effects may also be seen if AMRIX is taken with other CNS depressants.
Caution patients about operating an automobile or other hazardous machinery until it is reasonably certain that AMRIX therapy will not adversely affect their ability to engage in such activities. Advise patients to take AMRIX at approximately the same time each day. Manufactured for: Teva Pharmaceuticals Parsippany, NJ 07054 Manufactured By: Adare Pharmaceuticals, Inc.
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