APA: Most Bipolar Patients Start on Off-Label Antidepressants

SAN DIEGO, May 24 -- Antidepressants are widely used to treat the depression in bipolar disorder, despite their lack of approval for the indication and limited evidence of efficacy and safety, investigators reported here.

A review of nationwide prescribing patterns of psychotropic drugs for patients with diagnosed bipolar disorder revealed that more than half received antidepressants as initial monotherapy, with anticonvulsant drugs coming in a distant second, reported Ross J. Baldessarini, M.D., of Harvard, and colleagues.

"Utilization rates for antidepressants were very high despite a lack of compelling evidence of their efficacy or safety in bipolar depression, and polytherapy came to dominate treatment by one year," the investigators wrote in a poster presentation at the meeting of the American Psychiatric Association here.

The FDA has approved several antimanic and mood stabilizing agents for the treatment of depression associated with bipolar disorder. Antidepressants, although not approved for this indication, are increasingly being used off-label as monotherapy and in combination, the authors noted.

To get a snapshot of how specific drugs and combinations are being used to treat bipolar disorder, the investigators used a HIPAA-compliant, national health-plan claims database for the years 2000 through 2004 to identify patients with an International Classification of Diseases, 9th revision (ICD-9) diagnosis of bipolar disorder.

To be included in the study, all patients had to have continuous benefits, have at least one prescription filled for bipolar disease therapy in the study period, and to have been untreated in the six months before the index prescription was filled.

They identified a total of 7,567 patients with bipolar disorder, 57% men, 43% women, with a mean age of 35.5 12.4 years. In all, 55.2% of patients had type I bipolar disorder, 14.5% had type II, and 30.3% had a disorder not otherwise specified.

The large majority of the patients (74.9%) had one initial prescription, while the remaining 36.1% had prescriptions for two or more mood-altering drugs.

The initial monotherapies, in rank from first to last, were:

• Antidepressants: 56.1%
• Anticonvulsants: 13.9%
• Antipsychotics: 10.6%
• Lithium: 5.7%

Among the patients receiving anticonvulsants, valproate (Depakote, Depakene) was prescribed for 10.2%, lamotrigine (Lamictal) for 2.9%, and carbamazepine (Carbetrol, Tegretol) for 0.8%.

Initial and overlapping combinations included: antidepressants in 9.9%, antipsychotics in 8.9%, anticonvulsants in 7.3%, lithium in 2.3%. The rank order for combinations was the same at one year, with 36.1% of patients still receiving monotherapy, 25.7% receiving two or more psychotropics, and 38.2% getting nothing.

Psychotropic prescriptions per patient averaged 1.29 at baseline, and 1.52 at one year. Among the 5,666 patients who initially filled just one prescription, 68.6% were for antidepressants, 14.6% were for anticonvulsants, 10.8% were for antipsychotics, and 6.0% were for lithium. The proportions were roughly the same for 2,732 patients who remained on monotherapy at one year.

Among 1,945 patients who were on combination therapy at one year, 83.4% were taking antidepressants, 58.2% antipsychotics, 56.3% anticonvulsants, and 23.6% were receiving lithium.

At one year, the largest proportion of patients, 39% were receiving no drug treatment for bipolar disorder.

"Combination therapy and no medication came to dominate treatment by one year," the authors wrote. "Prevalent non-treatment at 12 months encourages development of better-tolerated mood-stabilizing treatments."