The safety and efficacy of i.m. ziprasidone and olanzapine for treating acute agitation in patients with schizophrenia are described, along with factors to consider when evaluating the cost-effectiveness of these agents. Agitation is defined as excessive motor and verbal activity. Acute agitation has traditionally been treated with the combination of haloperidol 5 mg and lorazepam 2 mg i.m. Controlled trials have shown, however, that combination therapy of haloperidol or droperidol plus lorazepam i.m. is better than single-drug treatment at one hour but not earlier. Phase II and III clinical trials showed that both i.m. ziprasidone mesylate 10 mg and 20 mg and olanzapine 2.5 mg-10 mg controlled agitation faster in patients with schizophrenia than p.o. ziprasidone 2 mg and placebo. In addition, i.m. olanzapine 10 mg controlled agitation faster in patients with schizophrenia faster than haloperidol in 15 minutes. Olanzapine i.m. was also superior to placebo in patients with dementia and in patients with bipolar disorder with and without psychotic symptoms, suggesting that agitation may be a syndrome that is similar across a multitude of disease states. Dystonic reactions occurred in 2.6% of patients taking ziprasidone, compared with 9.2% of patients taking haloperidol. No patients receiving olanzapine experienced a dystonic reaction. Ziprasidone has been associated with prolonged QTc Intervals. Pharmaco-economic evaluations should include costs associated with repeat i.m. injections for agitated patients, increased time in the emergency room, case of switching from i.m. to oral therapy, adverse effects, and relapse, as well as medication costs. I.m. olanzapine and ziprasidone show promise for treating acute agitation in patients with schizophrenia, especially because of their safer adverse effect profile and faster onset of effectiveness compared with haloperidol.