Plasma concentrations of protriptyline and clinical effects in depressed women

We studied the relationship between side effects, clinical outcome and the drug plasma levels in 28 female depressed patients treated with protriptyline. After 3 1/2 weeks treatment, patients with plasma levels within a median range (630 to 900 nmol/l) showed better responses to the drug than patients with plasma levels outside this range. There were no statistically signficant correlations between plasma levels and side effect scores or 'corrected' side effect scores (scores after subtracting pretreatment values) for the group at any time after starting the treatment. But we found positive correlations between plasma levels and 'corrected' side effect scores for the neurotic subgroup after 14 and 21 days of treatment. Other correlations between plasma levels and side effect scores were non-significant.