Low dosage of levomepromazine did not increase plasma concentrations of fluvoxamine.
The cytochrome enzyme P450 2D6 (CYP2D6) is thought to play a role in the human metabolism of fluvoxamine. Levomepromazine is a potent inhibitor of CYP2D6. We coadministered a low dosage of levomepromazine and fluvoxamine in 15 patients and found that the low dosage of levomepromazine was effective in counteracting the fluvoxamine-induced insomnia and did not increase plasma fluvoxamine levels. These results suggest that the inhibition of CYP2D6 by levomepromazine has little effect on fluvoxamine metabolism. Therefore, a low dosage of levomepromazine, used as a hypnotic agent, appears to be effective and safe when coadministered with fluvoxamine. Since this was a pilot study without a placebo control, a double-blind placebo-controlled study is needed to confirm our preliminary findings.
Yoshimura
R
R
Department of Psychiatry, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan. yoshi621@med.uoeh-u.ac.jp
Ueda
N
N
Nakamura
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D065690:Cytochrome P-450 CYP2D6 Inhibitors; D003865:Major Depressive Disorder / Q000097:blood / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D016666:Fluvoxamine / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008728:Methotrimeprazine / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D016584:Panic Disorder / Q000097:blood / Q000188:drug therapy*; D007319:Sleep Initiation and Maintenance Disorders / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy; D016896:Treatment Outcome
D065690:Cytochrome P-450 CYP2D6 Inhibitors; D008728:Methotrimeprazine; D016666:Fluvoxamine