Hormonal
contraceptives increase the levels of
tizanidine by up to 4-fold: the blood pressure-lowering effect of
tizanidine was increased by 12/8 mmHg.
A
clinical response or adverse effect with
tizanidine might occur at lower doses of
tizanidine in patients taking hormonal
contraceptives, therefore during dose titration individual doses should be reduced initially.