Citalopram intravenous infusion in resistant obsessive-compulsive disorder: an open trial

Treatment with intravenous clomipramine is rapidly effective in some obsessive-compulsive disorder (OCD) patients unresponsive to orally administered serotonin reuptake inhibitors (SRIs). The selective serotonin reuptake inhibitor citalopram is effective for OCD when administered orally. We investigated whether intravenous citalopram would rapidly benefit OCD patients unresponsive to orally administered SRIs.

Thirty-nine adult outpatients participated in a 3-week open-label trial of intravenous citalopram. Eligible patients had moderate-to-severe DSM-IV OCD of > or = 1 year's duration, a baseline Yale-Brown Obsessive Compulsive Scale (YBOCS) score > or = 25, and no other active Axis I diagnosis and had failed at least 2 adequate oral SRI trials, excluding citalopram. Intravenous citalopram was administered daily for 21 days, followed by oral citalopram until treatment day 84. Intravenous citalopram was started at 20 mg/day and was increased to 40 to 80 mg/day as tolerated.

Intravenous citalopram was well tolerated even at higher doses (dropout rate = 2.6%). At day 21, 23 (59%) of the 39 patients had YBOCS score decreases of > or = 25%, of whom 4 had decreases of > or = 35%. Twenty-seven patients with YBOCS score decreases of > or = 20% were allowed to continue on treatment with oral citalopram, and by day 84, all had substantial further improvement. All 27 patients also showed significant improvement in several dimensions of quality of life.

Intravenous citalopram was safe and rapidly effective in a group of treatment-resistant OCD patients. The early onset of response suggests a means of accelerating OCD symptom relief and predicting response to oral citalopram treatment. Double-blind, double-dummy, placebo-controlled trials of intravenous versus oral citalopram in patients with treatment-resistant OCD are indicated.