Study objectives: We evaluate the efficacy of intramuscular ziprasidone in agitated patients with bipolar disorder or schizoaffective disorder bipolar type.

Methods: This was a subgroup analysis of 2 similarly designed, randomized, double-blind, fixed-dose, 24-hour studies of intramuscular ziprasidone in agitated patients with bipolar disorder or schizoaffective disorder bipolar type. Patients received 2-mg control dose (n=15) versus 10 mg (n=20) and 2-mg control dose (n=11) versus 20 mg (n=15; 80 mg maximum). Efficacy was assessed by Behavioral Activity Rating Scale (BARS), Clinical Global Impression Scale of Severity (CGI–S), and Positive and Negative Syndrome Scale Agitation items scores.

Results: The greatest reductions in agitation (mean change in BARS) at 2 hours and 4 hours after the first dose were seen with 20-mg intramuscular ziprasidone. At 4 hours, the greatest improvement in CGI–S was seen in the 20-mg ziprasidone group. Responder rates (≥2-point decrease in BARS at 1.5 hours after first dose) were 80% in the 20-mg group (P≤.01 versus 2-mg control) and 58% in the 10-mg group, similar to results in the primary studies. No dystonia or excessive sedation was reported in either dosage group; 1 patient in the 10-mg group experienced akathisia.

Conclusion: Ziprasidone at 10 and 20 mg intramuscularly was rapidly effective and well tolerated in agitated psychotic patients with bipolar spectrum diagnoses, with the 20-mg intramuscular dose producing the largest decrease in agitation. The 10-mg dosage level is not consistently effective.