Tizanidine Rifampicin

Rifampicin moderately decreases the plasma concentrations of tizanidine. 

In a placebo-controlled, crossover study in 10 healthy subjects, pre-treatment with rifampicin 600 mg daily for 5 days moderately reduced the AUC and peak level of a single 4-mg dose of tizanidine given on day 6 by about 50%, without altering the half-life. ... 

Rifampicin appears to be only a weak inducer of the cytochrome P450 isoenzyme CYP1A2, by which tizanidine is metabolised. ... 

Rifampicin moderately reduces the levels and effects of tizanidine. Because tizanidine dose is titrated to effect, this is probably not that clinically important. A small increase in dose might be required. 

Backman JT, Granf B MT, Neuvonen PJ. Rifampicin is only a weak inducer of CYPl A2-me-diated presystemic and systemic metabolic studies with tizanidine and caffeine. EurJ Clin Pharmacol (2006) 62,451-61. 

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See also in sourсe #XX -- [ ]

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