Pharmacokinetics of Mirtazapine from Orally Administered Tablets: Influence of Gender, Age and Treatment Regimen

The effect of gender, age and treatment regimen (single dosing or chronic dosing for 7 days) on the pharmacokinetic profile of mirtazapine was studied in four groups of volunteers. The groups consisted of 9 male adults (25–43 years of age), nine female adults (25–48 years), eight elderly males (65–74 years) and eight elderly females (65–74 years), who received daily oral doses of 20 mg of mirtazapine in the form of tablets. In all groups, chronic dosing resulted in approximately 10 per cent higher plasma levels at steady state than those predicted from the single-dose kinetic profile. Although statistically significant, this effect of treatment regimen was so small that it is considered as clinically inconsequential. Mirtazapine plasma levels in adult males were approximately 50 per cent of the overall mean of the combined other groups, after both single and multiple dosing. As a consequence, statistically significant effects of gender and of age were observed. However, these differences were not large enough to justify any dose adjustments.