//fpnotebook.com/
Cyclobenzaprine
Aka: Cyclobenzaprine, Flexeril
- See Also
- Antispasmodic Skeletal Muscle Relaxant
- Indications
- Acute back or Neck Pain interfering with sleep despite Analgesics
- Limit to short-course (<14 days)
- Mechanism
- Antispasmodic Skeletal Muscle Relaxant
- Centrally acting cyclical Antidepressant with Sedative qualities
- Tricyclic amine salt similar to Amitriptyline
- Reduces Muscle hyperactivity and somatic motor activity
- Mechanism may act at 5-H2 receptors, inhibiting descending serotonergic pathways in the cord
- Dosing: Immediate Release
- Start: 5 mg orally at bedtime (5 mg is as effective as 10 mg and with less sedation)
- Maximum: 10 mg orally three times daily (primarily at bedtime for pain interfering with sleep)
- Dosing: Extended Release
- Start 15 mg orally daily
- Maximum: 30 mg orally daily
- Contraindications
- Older patients
- See Medications to Avoid in Older Adults
- Seizure Disorder (if concurrently on Tramadol)
- Glaucoma
- Cardiac Arrhythmia
- Congestive Heart Failure
- Recent Myocardial Infarction
- Efficacy
- See Antispasmodic Skeletal Muscle Relaxant
- Poor evidence for benefit
- More effective than Placebo for first 4 days of Low Back Pain
- However, no significant functional or pain benefit at 1 week for Acute Low Back Pain (non-Traumatic, non-radicular)
- Adverse effects
- See Antispasmodic Skeletal Muscle Relaxant for precautions
- Common: Anticholinergic
- Fatigue
- Drowsiness
- Dry Mouth (Xerostomia)
- Urinary Retention
- Increased Intraocular Pressure
- Rare
- Arrhythmia
- Reflex Tachycardia
- Cyclobenzaprine may block alpha-1 Adrenergic Receptors resulting in vasodilation
- QRS Widening
- Fast-acting Sodium channel blockade (as with Amitriptyline)
- Seizure
- GABA Receptor inhibition may lower Seizure threshold
- Myocardial Infarction
- Serotonin Syndrome
- Risk when Cyclobenzaprine is combined with other serotonergic drugs
- References
- Borenstein (2003) Clin Ther 25(4): 1056-73 [PubMed]
- Browning (2001) Arch Intern Med 161: 1613-20 [PubMed]
- Tofferi (2004) Arthritis Rheum 51:9-13 [PubMed]