What is the recommended dose and frequency of Tizanidine (Zanaflex) for muscle relaxation?

Tizanidine Dosing and Frequency for Muscle Relaxation

The recommended starting dose of tizanidine (Zanaflex) is 2 mg up to three times daily, with a maximum daily dose of 36 mg, though the total daily dose should typically not exceed 24 mg. 1

Dosing Guidelines

Initial Dosing

• Start with 4 mg as a single dose 1
• Gradually increase in 2-4 mg steps to optimize effect 1
• Doses can be repeated at 6-8 hour intervals, up to 3 doses in 24 hours 1

Pharmacokinetics

• Peak effect occurs at 1-2 hours after administration 1
• Effects typically last 3-6 hours 1
• Food has complex effects on tizanidine pharmacokinetics that can significantly alter drug levels 2

Maximum Dosing

• Maximum single dose: Clinical experience with single doses >8 mg is limited 1
• Maximum daily dose: 36 mg, though daily doses >24 mg have limited clinical experience 1

Special Populations

Elderly Patients

• Start at a lower dose (2 mg up to three times daily) 3
• Monitor for:
  • Muscle weakness
  • Urinary function changes
  • Cognitive effects
  • Sedation
  • Orthostatic hypotension 3

Hepatic/Renal Impairment

• Significant dose reductions required in patients with liver or kidney disease 2
• Careful monitoring of liver function is recommended during the first 6 months of treatment 1

Monitoring and Precautions

Common Side Effects

• Sedation/drowsiness (most common) 4
• Dry mouth 4
• Dizziness 1
• Hypotension (dose-related, occurs in approximately 2/3 of patients with 8 mg dose) 1

Drug Interactions

• Contraindicated with CYP1A2 inhibitors 2
• Potential for many drug-drug interactions 3
• Use caution with concurrent antihypertensive therapy 1
• Should not be used with other α2-adrenergic agonists 1

Titration Strategy

1. Begin with 2-4 mg single dose 1
2. Assess response after 1-2 hours (peak effect time) 1
3. Increase by 2-4 mg increments to achieve optimal muscle tone reduction 1
4. Distribute doses throughout the day at 6-8 hour intervals 1
5. Individual titration is necessary due to wide interpatient variability in effective plasma concentrations 4, 5

Clinical Pearls

• Effects are dose-related, making it prudent to begin with lower doses to minimize side effects 1
• Consistent administration with respect to food intake is important to avoid fluctuations in drug levels 2
• Hypotensive effects may be minimized by careful titration and monitoring 1
• When discontinuing, especially after long-term use, a gradual taper is strongly recommended to avoid withdrawal symptoms 2

Tizanidine has demonstrated efficacy in reducing muscle tone by 21-37% in clinical trials, with improvement occurring in 60-82% of patients 4. Its alpha2-adrenergic mechanism provides effective muscle relaxation while potentially causing less subjective muscle weakness than alternatives like baclofen 4.