Prochlorperazine induces akathisia in emergency patients

Study objective: Prochlorperazine (PCZ), a commonly used antiemetic and analgesic agent, is known to cause akathisia. The incidence of akathisia after a single 10-mg dose of intravenous PCZ has not been prospectively evaluated. We determined the incidence and severity of PCZ-induced akathisia at 1 hour and the incidence of delayed akathisic symptoms at 48 hours. Methods: This prospective controlled study evaluated a convenience sample of 140 adult patients at a 400-bed, academic, tertiary-care medical center with an annual emergency department census of 95,000 patient visits. One hundred patients who received intravenous PCZ for the treatment of severe headache or vomiting constituted the PCZ group. Forty patients receiving nonakathisic intravenous therapy (eg, saline solution or antibiotics) served as control subjects. Patients were excluded if they had preexisting motor disorders (eg, restless-leg syndrome or Parkinson's disease) or if they recently had received any medication with extrapyramidal, anticholinergic, sedative, or antiakathisic properties. All patients underwent an akathisia assessment before and 1 hour after receiving their respective intravenous medications. An established scale was used to detect the presence of akathisia and grade its severity as mild, moderate, or severe. The delayed development of akathisic symptoms within 48 hours also was measured in the PCZ group. Results: Akathisia developed in 44 (44%) of the patients receiving PCZ within 1 hour(95% confidence interval, 34% to 54%). The akathisia was graded as mild, moderate, and severe in 14, 22, and 8 subjects, respectively. Delayed symptoms suggestive of akathisia developed in 3 other patients within 48 hours. None of the 40 control subjects developed akathisia. Conclusion: Single-dose intravenous PCZ frequently induced akathisia within 1 hour of administration. Acute akathisia was not observed in patients receiving intravenous saline solution or antibiotics. The delayed development of akathisia symptoms 48 hours after a single dose of intravenous PCZ was uncommon.