Flexeril, also called Cyclobenzaprine, is used to help relax certain muscles in your body. It helps relieve the pain, stiffness, and discomfort caused by strains, sprains, or injuries to your muscles. Flexeril acts on the central nervous system (CNS) for its effects.
Be sure to tell your doctor of any allergies you have whether it is to medication or food, preservatives, or dyes. Also, tell your doctor of any other medications you are taking, including vitamins and supplements, and any medical conditions you may have.
It is very important that you take this medicine exactly as your doctor tells you to. If you miss a dose of this medicine, take it as soon as you remember, unless it is almost time for your next dose. Do NOT double doses.
Get emergency help right away if any of the following occur: changes in the skin color of the face; fast or irregular breathing; large swellings that look like hives on the face, eyelids, mouth, lips, and/or tongue; puffiness or swelling of the eyelids or the area around the eyes; shortness of breath, troubled breathing, tightness in chest, and/or wheezing; or skin rash, hives, or itching.
Also, tell your doctor immediately if you have continued fainting.
Cyclobenzaprine hydrochloride 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 217°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. FLEXERIL 5 mg (Cyclobenzaprine HCl) is supplied as a 5 mg tablet for oral administration. FLEXERIL 10 mg (Cyclobenzaprine HCl) is supplied as a 10 mg tablet for oral administration. FLEXERIL tablets contain the following inactive ingredients: hypromellose, iron oxide, lactose, magnesium stearate, starch, and titanium dioxide. FLEXERIL 5 mg tablets also contain Yellow D&C #10 Aluminum Lake HT, and Yellow FD&C #6 Aluminum Lake.
Cyclobenzaprine has the following structural formula: