CARISOPRODOL AND ASPIRIN TABLETS, USP 7869-02
DESCRIPTION
Carisoprodol and Aspirin Tablets, USP is a combination product containing carisoprodol, a centrally-acting muscle relaxant, plus aspirin, an analgesic with antipyretic and antiinflammatory properties.
Chemically, carisoprodol is (+)-2-Methyl-2-propyl-1,3-propanediol carbamate isopropylcarbamate. Carisoprodol is a white, crystalline powder, having a mild, characteristic odor and a bitter taste. It is very slightly soluble in water; freely soluble in alcohol, in chloroform, and in acetone. Its molecular formula is C12H24N204, with a molecular weight of 260.34. The structural formula is:
Chemically, aspirin is salicylic acid acetate. It can appear as white crystals, commonly tabular or needle-like, or white crystalline powder. It is odorless or has a faint odor. It is slightly soluble in water; freely soluble in alcohol; soluble in chloroform and in ether; sparingly soluble in absolute ether. Its molecular formula is C9H804, with a molecular weight of 180.16. The structural formula is:
Each tablet, for oral administration, contains 200 mg of carisoprodol and 325 mg of aspirin. In addition, each tablet contains the following inactive ingredients: FD&C Red #40 aluminum lake, hydroxypropyl cellulose, lactose monohydrate, microcrystalline cellulose, silicon dioxide, sodium starch glycolate, corn starch, stearic acid and zinc stearate.
|
CLINICAL PHARMACOLOGY
Carisoprodol: Carisoprodol is a centrally-acting muscle relaxant that does not directly relax tense skeletal muscles in man. The mode of action of carisoprodol in relieving acute muscle spasm of local origin has not been clearly identified, but may be related to its sedative properties. In animals, carisoprodol has been shown to produce muscle relaxation by blocking interneuronal activity and depressing transmission of polysynaptic neurons in the spinal cord and in the descending reticular formation of the brain. The onset of action is rapid and lasts four to six hours.
Carisoprodol is metabolized in the liver and is excreted by the kidneys. It is dialyzable by peritoneal and hemodialysis.
Aspirin: Aspirin is a nonnarcotic analgesic with antiinflammatory and antipyretic activity. Inhibition of prostaglandin biosynthesis appears to account for most of its antiinflammatory and for at least part of its analgesic and antipyretic properties.
Aspirin is rapidly absorbed and almost totally hydrolyzed to salicylic acid following oral administration. Although aspirin has a half-life of only about 15 minutes, the apparent biologic half-life of salicylic acid in the therapeutic plasma concentration range is between 6 and 12 hours. Salicylic acid is eliminated by renal excretion and by biotransformation to inactive metabolites. Clearance of salicylic acid in the high-dose range is sensitive to urinary pH (see Drug Interactions ) and is reduced by renal dysfunction.
|
