Rheumatology Book



Aka: Cyclobenzaprine, Flexeril
  1. See Also
    1. Antispasmodic Skeletal Muscle Relaxant
  2. Indications
    1. Acute back or Neck Pain interfering with sleep despite Analgesics
      1. Limit to short-course (<14 days)
  3. Mechanism
    1. Antispasmodic Skeletal Muscle Relaxant
    2. Centrally acting cyclical Antidepressant with Sedative qualities
      1. Tricyclic amine salt similar to Amitriptyline
    3. Reduces Muscle hyperactivity and somatic motor activity
      1. Mechanism may act at 5-H2 receptors, inhibiting descending serotonergic pathways in the cord
  4. Dosing: Immediate Release
    1. Start: 5 mg orally at bedtime (5 mg is as effective as 10 mg and with less sedation)
    2. Maximum: 10 mg orally three times daily (primarily at bedtime for pain interfering with sleep)
  5. Dosing: Extended Release
    1. Start 15 mg orally daily
    2. Maximum: 30 mg orally daily
  6. Contraindications
    1. Older patients
      1. See Medications to Avoid in Older Adults
    2. Seizure Disorder (if concurrently on Tramadol)
    3. Glaucoma
    4. Cardiac Arrhythmia
    5. Congestive Heart Failure
    6. Recent Myocardial Infarction
  7. Efficacy
    1. See Antispasmodic Skeletal Muscle Relaxant
    2. Poor evidence for benefit
      1. More effective than Placebo for first 4 days of Low Back Pain
      2. However, no significant functional or pain benefit at 1 week for Acute Low Back Pain (non-Traumatic, non-radicular)
  8. Adverse effects
    1. See Antispasmodic Skeletal Muscle Relaxant for precautions
    2. Common: Anticholinergic
      1. Fatigue
      2. Drowsiness
      3. Dry Mouth (Xerostomia)
      4. Urinary Retention
      5. Increased Intraocular Pressure
    3. Rare
      1. Arrhythmia
        1. Reflex Tachycardia
          1. Cyclobenzaprine may block alpha-1 Adrenergic Receptors resulting in vasodilation
        2. QRS Widening
          1. Fast-acting Sodium channel blockade (as with Amitriptyline)
      2. Seizure
        1. GABA Receptor inhibition may lower Seizure threshold
      3. Myocardial Infarction
      4. Serotonin Syndrome
        1. Risk when Cyclobenzaprine is combined with other serotonergic drugs
  9. References
    1. Borenstein (2003) Clin Ther 25(4): 1056-73 [PubMed]
    2. Browning (2001) Arch Intern Med 161: 1613-20 [PubMed]
    3. Tofferi (2004) Arthritis Rheum 51:9-13 [PubMed]
Medication Costs
Cyclobenzaprine (on 6/18/2017 at Walmart.com)
Cyclobenzaprine 10mg #30 tablets for $4.00 $0.13 each
Cyclobenzaprine 10mg #90 tablets for $10.00 $0.11 each
Cyclobenzaprine 5mg #30 tablets for $4.00 $0.13 each
Cyclobenzaprine 5mg #90 tablets for $10.00 $0.11 each
cyclobenzaprine (on 5/17/2017 at Medicaid.Gov Pharmacy Drug pricing)
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information.

cyclobenzaprine (C0056732)

Definition (NCI) A centrally acting skeletal muscle relaxant with antidepressant activity. The exact mechanism of action of cyclobenzaprine has not been fully determined, but this drug seems to primarily act at the brain stem to reduce tonic somatic motor activity, influencing both gamma and alpha motor neurons leading to a reduction in muscle spasms.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH C004704
SnomedCT 373779004, 80802008
LNC LP17189-9, MTHU004256
English cyclobenzaprine, N,N-dimethyl-3-(dibenzo(a,d)cycloheptene-4-ylidene)propylamine, cyclobenzaprine [Chemical/Ingredient], CYCLOBENZAPRINE, Cyclobenzaprine, Cyclobenzaprine (product), Cyclobenzaprine (substance)
Spanish ciclobenzaprina (producto), ciclobenzaprina (sustancia), ciclobenzaprina
Derived from the NIH UMLS (Unified Medical Language System)

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