Cyclobenzaprine (Flexeril) 5 mg Dosing Frequency
Cyclobenzaprine 5 mg should be taken three times daily (TID), approximately every 8 hours, as needed for muscle spasm. This is the standard dosing regimen supported by both FDA labeling and clinical trial evidence 1, 2.
Standard Dosing Protocol
The immediate-release formulation of cyclobenzaprine 5 mg is administered:
- Three times daily (TID)
- Every 8 hours as needed
- Maximum duration: 2-3 weeks 1
This dosing frequency is based on cyclobenzaprine's 4-6 hour duration of action, requiring TID dosing to maintain therapeutic coverage and avoid painful untreated intervals between doses 2.
Evidence Supporting This Regimen
Clinical trials demonstrate that cyclobenzaprine 5 mg TID is as effective as 10 mg TID but with significantly lower sedation rates 2. In two large placebo-controlled trials involving 1,405 patients with acute musculoskeletal spasm, the 5 mg TID regimen showed:
- Significantly higher efficacy scores versus placebo (P ≤ 0.001) on all primary measures
- Onset of relief within 3-4 doses
- Meaningful treatment effect independent of sedation
- Better tolerability profile than the 10 mg dose 2
Important Clinical Caveats
Duration limitation: Use beyond 2-3 weeks is not recommended, as cyclobenzaprine is indicated only for acute musculoskeletal conditions 1.
Withdrawal considerations: With long-term use, patients may experience withdrawal symptoms (malaise, nausea, headache) for 2-4 days after discontinuation. While uncomfortable, these are not life-threatening. Taper over 2-3 weeks if discontinuing after prolonged use 3.
Anticholinergic effects: Monitor for confusion, drowsiness, constipation, urinary retention, and dry mouth—particularly in elderly patients who have 40% higher drug exposure and prolonged half-life (50 hours vs 32 hours in younger adults) 1.
Drug interactions: Avoid concurrent use with MAO inhibitors due to serotonin syndrome risk. Exercise caution with other sedatives and anesthetic agents 3.
Alternative Formulation
Note that an extended-release formulation exists (15-30 mg once daily), but this is a different product than the immediate-release 5 mg tablets you're asking about 1.