Patients with the CYP2D6*5 allele in combination with another no function allele may have a decreased clearance of mirtazapine as compared to patients with the two normal function alleles. This drug-variant pair has been assigned a 鈥渘o recommendation鈥?by DPWG, as it was determined to be not clinically actionable. Other genetic and clinical factors may also influence metabolism of mirtazapine. This annotation only covers the pharmacokinetic relationship between CYP2D6 and mirtazapine and does not include evidence about clinical outcomes.