Venlafaxine, a new antidepressant, inhibits reuptake of norepinephrine
and serotonin without appreciable effects on histaminergic, alpha-adr
energic, or cholinergic systems. Pharmacologically the drug is unique:
the half-life is short and it exerts both rapid and prolonged beta-ad
renergic desensitization after single doses in a rodent model. Venlafa
xine has been thought to possess a rapid onset of clinical antidepress
ant action. Accordingly, two clinical studies in which moderate amount
s of venlafaxine were given aggressively were reviewed to examine aspe
cts of the drug's onset of action. Three statistical methodologies wer
e employed-traditional analysis of depression scale scores, pattern an
alysis based on timing and persistence of response, and survival analy
sis of sustained response. All three methods showed venlafaxine to hav
e significant effects early in the course of therapy. In addition, ven
lafaxine is the first drug to meet criteria for early onset using the
pattern analysis methodology. Depressed patients aggressively treated
with venlafaxine show significant benefit on or before Day 7 of treatm
ent using traditional methods of analysis as well as survival analysis
of sustained response.