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Amrix

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AMRIX®
(cyclobenzaprine hydrochloride) Extended-Release Capsules

DRUG DESCRIPTION

AMRIX® (Cyclobenzaprine Hydrochloride Extended-Release Capsules) 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 C20H21N·HCl and a molecular weight of 311.9. It has a melting point of 2l7°C, and a pKa 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®
  (Cyclobenzaprine Hydrochloride Extended-Release Capsules) Structural Formula Illustration

AMRIX (cyclobenzaprine hcl extended-release capsules) extended-release capsules for oral administration are supplied in 15 and 30 mg strengths. AMRIX (cyclobenzaprine hcl extended-release capsules) 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 (cyclobenzaprine hcl extended-release capsules) 15 mg capsules also contain red ferric oxide and yellow ferric oxide. AMRIX (cyclobenzaprine hcl extended-release capsules) 30 mg capsules also contain FD&C blue #1, FD&C blue #2, FD&C red #40, and FD&C yellow #6.

What are the possible side effects of cyclobenzaprine (Amrix, Comfort Pac with Cyclobenzaprine, Fexmid, Flexeril)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using cyclobenzaprine and call your doctor at once if you have any of these serious side effects:

  • fast, pounding, or uneven heartbeats;
  • chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
  • sudden numbness or weakness, especially on one...

Read All Potential Side Effects and See Pictures of Amrix »

What are the precautions when taking cyclobenzaprine hcl extended-release capsules (Amrix)?

Before taking cyclobenzaprine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: an overactive thyroid (hyperthyroidism), certain heart problems (irregular heartbeat, congestive heart failure, heart block/rhythm disorders, recent heart attack).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: severe difficulty urinating (urinary retention), high pressure inside the eyes (glaucoma), liver...

Read All Potential Precautions of Amrix »

Last reviewed on RxList: 6/3/2008
This monograph has been modified to include the generic and brand name in many instances.

Amrix - User Reviews

Amrix User Reviews

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.


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