Tizanidine Dosage Adjustment
Yes, tizanidine dosage can be increased beyond 2 milligrams, with a maximum daily dose of 36 mg divided into three doses per day. 1
Recommended Dosing Guidelines
- The FDA-approved dosing recommends starting with 4 mg single doses, though lower starting doses of 2 mg are common in clinical practice 1
- Dose should be increased gradually in 2-4 mg increments to achieve optimal effect (satisfactory muscle tone reduction at a tolerated dose) 1, 2
- Doses can be repeated at 6-8 hour intervals, up to a maximum of three doses in 24 hours 1
- The total daily dose should not exceed 36 mg 1
- Maximum effects occur within 1-2 hours of administration and typically last 3-6 hours 1, 2
Important Considerations When Increasing Dose
- Wide interpatient variability exists in effective plasma concentrations, requiring individualized dose titration over 2-4 weeks 2
- Food has complex effects on tizanidine pharmacokinetics, which can result in clinically significant differences in drug effects 1
- Most common adverse effects include dry mouth and somnolence/drowsiness 2
- Tizanidine has significant drug interactions, particularly with ciprofloxacin, which is contraindicated due to increased tizanidine serum concentrations that potentiate hypotensive and sedative effects 3
Dosing Strategy for Muscle Spasticity
- Initial dose: 2-4 mg
- Titration: Increase by 2-4 mg increments every few days as needed and tolerated 1, 4
- Maximum single dose: Generally 8 mg, though single doses up to 12 mg have limited experience 1
- Daily dosing schedule: Divide into 2-3 doses per day, with 6-8 hours between doses 1
Monitoring During Dose Increases
- Monitor for excessive sedation, which may indicate need for dose reduction 2, 4
- Watch for hypotension, particularly when increasing doses 4
- Assess clinical response in terms of muscle tone reduction and functional improvement 2
- Be aware that subjective muscle weakness appears less problematic with tizanidine compared to other antispasmodics like baclofen 2
Special Populations
- For older persons, the American Geriatrics Society recommends starting at 2 mg up to three times daily 3
- Older patients rarely tolerate doses greater than 30-40 mg per day 3
- In pediatric patients with spastic quadriplegia, doses of 0.1-0.2 mg/kg/day divided into 2-3 doses have been used 5
Remember that tizanidine is a centrally-acting alpha-2 adrenergic receptor agonist with myotonolytic properties, and its dosage should be carefully titrated to balance efficacy and side effects.