Cyclobenzaprine

Introduction

  • Generic Name: Cyclobenzaprine
  • Brand Names: Flexeril, Amrix, Fexmid
  • Pharmacological Class: Muscle relaxant, tricyclic antidepressant derivative
  • Mechanism of Action: Acts at the brain stem to reduce tonic somatic motor activity, influencing both gamma and alpha motor systems.

Indications

  • Primary Use: Management of muscle spasms associated with acute painful musculoskeletal conditions.
  • Off-Label Use: Sometimes prescribed for fibromyalgia as a sleep aid and muscle relaxant.

Dosage

  • Adults: Typically, 5 mg to 10 mg three times a day. Dosage adjustments based on response and tolerance.
  • Elderly: Start at a lower dose to decrease the likelihood of side effects. Careful monitoring recommended.
  • Children: Use is not recommended in children under 15 due to a lack of safety data.

Administration

  • Method: Oral intake, with or without food, to avoid gastrointestinal upset.
  • Precautions: Ensure proper timing of doses to maintain effective relief throughout the day.

Forms Available

  • Immediate Release Tablets: 5 mg, 7.5 mg, 10 mg
  • Extended Release Capsules: 15 mg, 30 mg, allowing for once-daily dosing in some patients.

Side Effects

  • Common: Drowsiness, dry mouth, and dizziness, affecting daily activities.
  • Less Common: Blurred vision, confusion, fatigue, which may diminish over time.
  • Rare but Serious: Severe cardiac events, hepatic impairment, potentially life-threatening serotonin syndrome.

Warnings

  • Black Box Warnings: The risk of significant cardiac events from overdose.
  • Contraindications: Marked by contraindications including recent myocardial infarction and acute recovery phase of heart attacks.

Precautions

  • General: Monitor for signs of urinary retention and angle-closure glaucoma.
  • Health Conditions: Particular care is needed in those with a history of cardiac conditions or hyperthyroidism.

Interactions

  • Medications: Enhanced sedation with CNS depressants, potential severe interactions with MAO inhibitors.
  • Food: No significant food interactions, but caution advised with alcohol.

Monitoring Parameters

  • Vital Signs: Regular monitoring of blood pressure and heart rate recommended.
  • Blood Tests: Liver function tests and periodic blood counts are advisable.

Use in Children

  • Guidelines: Not approved for anyone under 15; limited data on safety and efficacy.

Use in Pregnancy

  • FDA Category: B. Animal studies have not demonstrated a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women.

Use in Elderly

  • Considerations: Greater frequency of hepatic, renal, or cardiac impairment may necessitate dose adjustments.

Use in Kidney Disease

  • Adjustments: Usually not required, but monitor for increased drug effects or side effects.

Use in Liver Disease

  • Caution: Significant alterations in dosage may be needed depending on liver function.

Patient Counselling Points

  • Instructions: Take medication exactly as prescribed to minimize risk of side effects.
  • Side Effects: Encourage reporting of all side effects, especially those that are severe or persistent.
  • Lifestyle: Discuss potential impacts on daily living and operating machinery.

Table of Brand Names, Manufacturer, and Prices in USD

Brand NameManufacturerStrength/Dosage FormPrice (USD)
FlexerilMerck & Co.10 mg Tablet$2.00
AmrixTeva Pharmaceuticals30 mg Capsule ER$8.00
FexmidCipla7.5 mg Tablet$1.50

15 FAQs with Answers

  1. What is Cyclobenzaprine used for? – To alleviate muscle spasms in acute musculoskeletal conditions.
  2. Can Cyclobenzaprine be used by children? – Not recommended for use in children under 15 years of age.
  3. How should I take Cyclobenzaprine? – Take orally, can be with or without food to reduce stomach upset.
  4. What are the common side effects? – Includes drowsiness, dry mouth, and dizziness.
  5. Is Cyclobenzaprine safe during pregnancy? – Considered Category B, but always consult a healthcare provider.
  6. Can Cyclobenzaprine be combined with alcohol? – Alcohol may enhance drowsiness and dizziness; avoid.
  7. What is the recommended duration for taking Cyclobenzaprine? – Generally limited to short-term use, typically no longer than 2-3 weeks.
  8. What should I avoid while taking Cyclobenzaprine? – Avoid driving or operating heavy machinery if feeling drowsy.
  9. What are signs of an overdose of Cyclobenzaprine? – Extreme drowsiness, rapid heartbeat, confusion are indicators.
  10. Is Cyclobenzaprine addictive? – It’s not considered addictive, but it can cause dependence if used long-term.
  11. Should I stop taking Cyclobenzaprine suddenly? – Consult with your healthcare provider before stopping to discuss tapering.
  12. What are the rare but serious side effects of Cyclobenzaprine? – Includes severe cardiac issues and serotonin syndrome.
  13. What other medications interact with Cyclobenzaprine? – Interacts significantly with other CNS depressants and MAO inhibitors.
  14. Who should not take Cyclobenzaprine? – Individuals with recent myocardial infarction, untreated glaucoma, or severe liver impairment.
  15. How does Cyclobenzaprine work to relieve muscle spasms? – It acts on the central nervous system to block nerve impulses.