| Item |
Information |
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Drug Groups
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approved |
|
Description
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Cyclobenzaprine is a skeletal muscle relaxant and a central nervous system (CNS) depressant. Cyclobenzaprine acts on the locus coeruleus where it results in increased norepinephrine release, potentially through the gamma fibers which innervate and inhibit the alpha motor neurons in the ventral horn of the spinal cord. It is structurally similar to Amitriptyline, differing by only one double bond. |
| Indication |
For use as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute, painful musculoskeletal conditions. |
| Pharmacology |
Cyclobenzaprine, closely related to the antidepressant amitriptyline, is used as a skeletal muscle relaxant to reduce pain and tenderness and improve mobility. Unlike dantrolene, cyclobenzaprine cannot be used to treat muscle spasm secondary to cerebral or spinal cord disease. |
| Toxicity |
Oral mouse and rat LD50 are 338 mg/kg and 425 mg/kg respectively. Signs of overdose include agitation, coma, confusion, congestive heart failure, convulsions, dilated pupils, disturbed concentration, drowsiness, hallucinations, high or low temperature, increased heartbeats, irregular heart rhythms, muscle stiffness, overactive reflexes, severe low blood pressure, stupor, and vomiting. |
| Affected Organisms |
| • |
Humans and other mammals |
|
| Biotransformation |
Extensively metabolized (gastrointestinal and hepatic). |
| Absorption |
Slowly but well absorbed after oral administration |
| Half Life |
18 hours (range 8-37 hours) |
| Protein Binding |
Very high (93%) |
| Elimination |
Cyclobenzaprine is extensively metabolized, and is excreted primarily as glucuronides via the kidney. |
| Clearance |
* 0.7 L/min |
| External Links |
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