Effect of smoking on neuroleptics in schizophrenia.
OBJECTIVE
The effect of smoking on daily doses and plasma levels of neuroleptics prescribed for schizophrenic patients was studied.


METHODS
90 outpatients with schizophrenic disorder (DSM-III-R) who were on a stable regimen of psychotropic medication and showed a stable clinical state were included in a double-blind placebo-controlled trial. Data were collected and blood tests taken at the baseline interview. The plasma levels were obtained for 52 patients.


RESULTS
Daily neuroleptic doses converted to chlorpromazine equivalents correlated significantly (r = 0.436) with the plasma levels of their unmetabolised fractions. The neuroleptic doses increased with age in smokers, while in nonsmokers they decreased. Neither sex, age nor smoking had a significant association with the neuroleptic plasma levels.


CONCLUSIONS
Smoking seems to lead to increased neuroleptic dosages in postmenopausal schizophrenics by increasing hepatic metabolism and renal excretion of the drugs and possibly enhancing dopamine release. It is also possible that older smoking patients form a selected group of heavy smoker and they, therefore, need exceptionally high neuroleptic doses.
Salokangas
R K
RK
Department of Psychiatry, University of Turku, Turku University Central Hospital, Finland.
Saarijärvi
S
S
Taiminen
T
T
Lehto
H
H
Niemi
H
H
Ahola
V
V
Syvälahti
E
E
D000328:Adult; D000367:Age Factors; D000368:Aged; D014150:Antipsychotic Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D015283:Citalopram / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy*; D012565:Schizophrenic Psychology; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects* / Q000097:blood / Q000523:psychology
D014150:Antipsychotic Agents; D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors