Mirtazapine instructions for administration

Instructions for administration
Initial treatment Elderly/patients with renal or hepatic impairment Maintenance/extended treatment Switching patients to/from monoamine oxidase inhibitor

Initial treatment
The recommended starting dose for Mirtazapine tablets USP is 15 mg/day, administered in a single dose, preferably in the evening prior to sleep. In the controlled clinical trials establishing the efficacy of Mirtazapine in the treatment of major depressive disorder, the effective dose range was generally 15 mg/day to 45 mg/day. While the relationship between dose and satisfactory response in the treatment of major depressive disorder for Mirtazapine has not been adequately explored, patients not responding to the initial 15 mg dose may benefit from dose increases up to a maximum of 45 mg/day. Mirtazapine has an elimination half-life of approximately 20 to 40 hours, therefore, dose changes should not be made at intervals of less than one to two weeks in order to allow sufficient time for evaluation of the therapeutic response to a given dose. Return to top

Elderly/patients with renal or hepatic impairment
The clearance of Mirtazapine is reduced in elderly patients and in patients with moderate to severe renal or hepatic impairment. Consequently, the prescriber should be aware that plasma Mirtazapine levels may be increased in these patient groups, compared to levels observed in younger adults without renal or hepatic impairment. Return to top

Maintenance/extended treatment
It is generally agreed that acute episodes of depression require several months or longer of sustained pharmacological therapy beyond response to the acute episode. Systematic evaluation of Mirtazapine tablets USP has demonstrated that its efficacy in major depressive disorder is maintained for periods of up to 40 weeks following 8 to 12 weeks of initial treatment at a dose of 15 mg/day to 45 mg/day. Based on these limited data, it is unknown whether or not the dose of Mirtazapine needed for maintenance treatment is identical to the dose needed to achieve an initial response. Patients should be periodically reassessed to determine the need for maintenance treatment and the appropriate dose for such treatment. Return to top

Switching patients to/from monoamine oxidase inhibitor
At least 14 days should elapse between discontinuation of an MAOI and initiation of therapy with Mirtazapine. In addition, at least 14 days should be allowed after stopping Mirtazapine before starting an MAOI. Return to top