How to Write a Prescription for Tizanidine
Start tizanidine at 2 mg orally up to three times daily, with gradual titration in 2-4 mg increments every 3-7 days to achieve optimal spasticity control while monitoring closely for hypotension and sedation, not exceeding 36 mg total daily dose. 1, 2
Initial Prescription Parameters
Starting Dose
- Begin with 2 mg orally up to three times daily as recommended by the American Geriatrics Society, which represents the safest starting point across all patient populations 1
- The FDA label indicates that while 4 mg is the minimum dose shown effective in controlled trials, the dose-related nature of adverse events makes starting at 4 mg prudent only after assessing tolerance 2
- For elderly patients specifically, the American Geriatrics Society emphasizes starting at 2 mg due to increased sensitivity to sedative and hypotensive effects 3
Dosing Schedule
- Administer doses at 6-8 hour intervals with a maximum of three doses in 24 hours 2
- Consider giving the initial dose at bedtime to allow sedation to occur during sleep, particularly during the titration phase 3
- Peak effect occurs at 1-2 hours post-dose, with duration of 3-6 hours 2
Titration Protocol
Dose Escalation
- Increase by 2-4 mg increments every 3-7 days based on patient tolerance and therapeutic response 2, 4
- Titrate to the lowest effective dose that provides satisfactory muscle tone reduction at a tolerated level 2
- The optimal dosage must be individualized over 2-4 weeks due to wide interpatient variability in effective plasma concentrations 4
Maximum Dosing
- Total daily dose should not exceed 36 mg per day 2
- Single doses should not exceed 8 mg in most cases, as experience with single doses exceeding 8 mg and daily doses exceeding 24 mg is limited 2
- Older adults rarely tolerate doses greater than 30-40 mg per day 3, 1
Critical Prescribing Considerations
Food Effects
- Counsel patients to take tizanidine consistently either with or without food - switching between fed and fasted states can cause clinically significant pharmacokinetic differences that may result in increased adverse events or altered onset of activity 2
Contraindications and Cautions
- Avoid in patients with hepatic or renal dysfunction due to reduced clearance and increased risk of adverse effects 3, 1
- Do not use with other α2-adrenergic agonists 2
- Exercise extreme caution when prescribing with concurrent antihypertensive therapy or opioids due to additive hypotensive effects 3, 2
- Avoid in patients taking CYP1A2 inhibitors (e.g., ciprofloxacin, fluvoxamine) as tizanidine clearance is significantly reduced 3
Monitoring Requirements
- Monitor liver function tests (ALT/AST) during the first 6 months of treatment - approximately 5% of patients develop elevations >3 times upper limit of normal, and rare cases of fatal hepatic failure have been reported 2
- Monitor blood pressure closely, especially after initial dosing and dose increases - two-thirds of patients treated with 8 mg experience a 20% reduction in diastolic or systolic BP within 1-3 hours 2
- Assess for orthostatic hypotension, particularly when patients move from supine to upright position 2
- Monitor for excessive sedation, muscle weakness, urinary function changes, and cognitive effects 3
Common Pitfalls to Avoid
Discontinuation Error
- Never abruptly discontinue tizanidine in long-term users - the dose must be tapered slowly due to risk of withdrawal symptoms including rebound tachycardia, hypertension, and hypertonia 3, 1, 2
Drug Interactions
- Review all current medications before prescribing, particularly CNS depressants (pregabalin, quetiapine, duloxetine, benzodiazepines) which have additive sedative effects 3
- When combined with opioids like oxycodone, the risk of hypotension is significantly increased through additive mechanisms 3
Inappropriate Indications
- Tizanidine is specifically for treating spasticity (increased muscle tone), not hypotonia (reduced muscle tone) 1, 5
- While studies show efficacy for acute low back pain, this is not an FDA-approved indication and treatment duration should be limited to 2 weeks or less 1, 5
Sample Prescription Format
Tizanidine 2 mg tablets
- Sig: Take 1 tablet by mouth three times daily (every 6-8 hours)
- Dispense: #90 tablets
- Refills: 0 (reassess before refilling)
- Instructions: Take consistently with or without food. Do not switch between taking with meals and on empty stomach. May cause drowsiness and low blood pressure - rise slowly from sitting/lying position. Report any yellowing of skin/eyes, severe drowsiness, or muscle weakness immediately.