25–50 Dose as in normal renal function <25 Initial dose 2 mg once daily and slowly increase by 2 mg increments. Increase daily dose before increasing frequency of administration
DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES
CAPD                : Unknown dialysability. Dose as in GFR<25 mL/min
HD                     : Unknown dialysability. Dose as in GFR<25 mL/min
HDF/high flux   : Unknown dialysability. Dose as in GFR<25 mL/min
CAV/VVHD      : Unknown dialysability. Dose as in GFR=25–50 mL/min
IMPORTANT DRUG INTERACTIONS
Potentially hazardous interactions with other drugs
Anti-arrhythmics: enhanced muscle relaxant effect with procainamide
Antibacterials: concentration increased by ciprofloxacin – avoid concomitant use Antihypertensives: enhanced hypotensive effect Oral contraceptives: clearance of tizanidine reduced by 50%
ADMINISTRATION
Reconstition
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Route
Oral
Rate of Administration
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Comments
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OTHER INFORMATION
Pharmacokinetic data suggest that renal clearance in the elderly may be decreased by up to 3-fold May induce hypotension; therefore may potentiate the effect of antihypertensive drugs, including diuretics – exercise caution With beta-blockers or digoxin, may potentiate hypotension or bradycardia LFTs should be monitored monthly for the first 4 months Tizanidine undergoes rapid and extensive first pass metabolism. The metabolites (mainly inactive) constitute 70% of the administered dose and are excreted via the renal route