Elevated norharman plasma levels in alcoholic patients and controls resulting from tobacco smoking

Plasma norharman and harman levels were measured by solvent extraction and HPLC with fluorescence detection in alcohol-dependent patients undergoing in-patient abstinence treatment and in control subjects. In both groups, randomly collected samples from smokers contained higher mean norharman levels than those from nonsmokers. In three volunteers norharman concentrations rose sharply after smoking of one or two cigarettes and declined to near-basal levels within one hour after one cigarette. When 12 patients kept a smoking-free interval of at least 6 h, they had similarly low plasma norharman concentrations (20 +/- 8 pg/ml) as 18 non-smoking control subjects (17 +/- 8 pg/ml) or as 13 smoking controls who had abstained from smoking (20 +/- 6 pg/ml). Ten of the patients smoked one cigarette and within 5 - 10 min attained norharman levels of 177 +/- 147 pg/ml plasma. The high prevalence of smokers among chronic alcoholics probably explains the previous finding of elevated norharman plasma levels in these patients.