DIRECT COST OF DEPRESSION - ANALYSIS OF TREATMENT COSTS OF PAROXETINEVERSUS IMIPRAMINE IN CANADA

Objective: To assess the potential economic impact of new and move exp ensive antidepressants on the overall cost of treatment using cost-eff ectiveness analysis. Method: For this analysis, a computerized decisio n tree of clinical practice was developed to model the 12-month treatm ent of moderate to severe depression in Canada. To complete the model, data were obtained from physician panels, the Ontario Ministry of Hea lth, and clinical comparative trials of paroxetine, a selective seroto nin reuptake inhibitor and imipramine, a tricyclic antidepressant. Res ults: The overall cost of treatment when paroxetine 30 mg per day was used first-line was found to be lower than when generic imipramine was used as the initial therapy ($1697 versus $1793). The higher drug cos t of paroxetine ($1.69 per day) versus imipramine ($0.05 per day) was offset by a higher rate of treatment failures with the tricyclic neces sitating an alternate therapy, additional physician visits and/or hosp italization. Sensitivity analysis of key variables determined that dru g price and relapse rates after discontinuation were relatively insens itive predictors of the overall cost of care. More important was the c ontinuation rate while on different therapies. Conclusion: Paroxetine demonstrated a cost-benefit relative to imipramine when the continuati on rate was greater than or equal to 47%. Clinical trials of paroxetin e have reported continuation rates of 41% to 65%, suggesting that paro xetine is a cost-effective alternative to imipramine in the 1-year man agement of patients with moderate to severe depression.