Doxepin plasma levels and anxiolytic response.

A study of 23 patients (16 females, 7 males), diagnosed as suffering from anxiety, was carried out using a flexible dosage regimen of doxepin. Hamilton Anxiety Rating Scale scores were assessed on days 0, 7, 14 and 21 and plasma doxepin and desmethyl-doxepin concentrations were analysed from blood samples taken on days 7, 14 and 21 of the trial. No simple correlation between the Hamilton score at day 21 and plasma doxepin concentration (rs = -0.099 p greater than 0.05; n = 19) or plasma desmethyldoxepin concentration (rs = 0.339; p greater than 0.05; n = 19) was obtained. The sum of doxepin and desmethyldoxepin concentrations was not correlated with Hamilton score at day 21 (rs = 0.276; p greater than 0.05; n = 19). No correlation of doxepin, desmethyldoxepin or total concentrations and Hamilton score was found on days 7 or 14 of the trial.