ON THE PROBLEMS OF SWITCHING FROM INTRAVENOUS TO ORAL-ADMINISTRATION IN DRUG-TREATMENT OF ENDOGENOUS-DEPRESSION - A PLACEBO-CONTROLLED DOUBLE-BLIND TRIAL WITH DOXEPIN

In the treatment of depressive disorders the onset of action can be ac celerated if the antidepressant drug is initially administered by intr avenous infusion. It is not. clear whether this effect is due to pharm acological or to psychological effects of the infusion setting. The ne cessary switch to oral administration may be problematic. Uncontrolled observations indicate that it could be associated with a remarkable d eterioration in the course of the disease. This randomized double-blin d placebo-controlled study on doxepin is the first investigation of th e effect of the switch from parenteral to oral administration on sympt oms of endogenous depression. The hypothesis to be tested, that there is a significant worsening of treatment response during the switch, mu st be rejected on the basis of objective and subjective psychometric t ests. There was in fact a continuous improvement. Precondition was a s election of patients with typical ''endogenous'' depressions and maint enance of at least constant plasma levels of the active antidepressant s. In patients under the age of 65 years this can generally be achieve d by switching in a ratio of 125 mg i.v. to 250 per os in the case of doxepin. Individual case studies indicated that a worsening in the pat ient's progress after switching was correlated with a decreasing plasm a level of the active drug. Low plasma level already during the infusi on period, insufficient response, and questionable compliance on oral medication were associated. Due to large interindividual differences o f plasma levels by a factor of 10, measurements before and after switc hing are required.