What is the maximum recommended dose of tizanidine for a healthy adult weighing approximately 103 lb (47 kg)?

Maximum Tizanidine Dose for 103.2 Pounds (46.8 kg)

The maximum recommended dose of tizanidine is 36 mg per day (divided into up to three doses), regardless of body weight, as this is an absolute ceiling established by the FDA. 1

Standard Dosing Parameters

• Total daily maximum: 36 mg per day, administered as up to three doses in 24 hours 1
• Single dose maximum: 12 mg per dose (though experience with repeated single doses exceeding 12 mg is limited) 1
• Dosing interval: 6 to 8 hours between doses as needed 1

The FDA label explicitly states there is "essentially no experience with repeated, single, daytime doses greater than 12 mg or total daily doses greater than 36 mg," making this an absolute safety ceiling. 1

Practical Dosing Strategy

Start low and titrate slowly:

• Begin with 4 mg as a single oral dose 1
• Increase gradually in 2 to 4 mg increments to achieve optimal effect (satisfactory muscle tone reduction at a tolerated dose) 1
• The dose-related nature of adverse events (particularly sedation and hypotension) makes gradual titration essential 1

Typical effective dosing range:

• Clinical trials have used dosages ranging from 2 to 36 mg/day, with wide interpatient variability in effective plasma concentrations 2
• In one study, 50% of patients achieved adequate spasticity control with 12 mg daily of modified-release formulation 3
• Optimal daily doses in clinical trials ranged from 8 to 36 mg for immediate-release tizanidine 4

Critical Safety Considerations for This Weight

Body weight does NOT modify the maximum dose ceiling:

• At 103.2 pounds (46.8 kg), this patient falls below typical adult weight, but tizanidine dosing is not weight-based 1
• The 36 mg daily maximum applies universally to adults regardless of body weight 1
• However, lower body weight may increase susceptibility to dose-related adverse effects (sedation, hypotension, dry mouth) 2, 5

Monitor closely for:

• Somnolence/drowsiness (most common adverse effect) 2, 5
• Dry mouth 2, 5
• Hypotension and bradycardia 6
• Fatigue 5

Important Caveats

Food effects matter significantly:

• Food has complex effects on tizanidine pharmacokinetics that can result in clinically significant differences in adverse events or onset of activity 1
• Maintain consistency in administration (always with food or always without food) to avoid unpredictable fluctuations 1

Peak effect timing:

• Maximum effects occur within 1 to 2 hours of administration 1
• Effects dissipate between 3 to 6 hours, which informs the 6-8 hour dosing interval 1

Contraindications:

• Absolutely contraindicated with ciprofloxacin and fluvoxamine due to significantly reduced clearance causing severe hypotension, bradycardia, and sedation 6
• Avoid in hepatic or renal dysfunction due to significant sedative and hypotensive effects 6