Intravenous versus oral administration of amitriptyline in patients with major depression

Antidepressants can be administered by different routes. Advantages for either the oral or the intravenous administration have been suggested from pharmacokinetic as well as from clinical points of view. Controlled comparison studies of the two routes do not provide unequivocal recommendations. In this investigation, amitriptyline was studied over a 4-week period consisting of a 2-week, double-blind/double-dummy phase with either oral (150 mg/day), high-dose intravenous (150 mg/day), or medium-dose intravenous (100 mg/day) treatment and a 2-week phase of open oral treatment in 80 patients with major depression. A psychopathologic assessment was made using the Hamilton Rating Scale for Depression, the Clinical Global Impressions Scale, the von Zerssen's "Befindlichkeitsskala," an adjective checklist, and a Visual Analog Scale. No significant differences were found concerning the mean scores of the rating scales or time of onset of action in the physicians' ratings. In the patients' self-ratings, there was an earlier therapeutic effect in the high-dose intravenous group. The number of improvers after 7 days was significantly higher in the high-dose intravenous group compared with both other groups. After 14 days, no significant differences in the numbers of improvers and responders between groups were detected. The results of this study do not clearly favor one of the tested options. The main differences found in this study seem to be dose-related rather than differentiating between oral and intravenous routes of administration.