Intravenous chlorpromazine for the emergency treatment of uncontrolled symptomatic hypertension in the pre-hospital setting: Data from 500 consecutive cases

Background: Chlorpromazine is a dopamine-receptor antagonist antipsychotic agent. Because of its strong alpha-blocking and sedative actions, it has also been used as emergency therapy for extreme arterial hypertension. Published reports to date have included very small numbers of patients (i.e., 5-30). Objectives: To analyze data on almost 500 patients who received intravenous chlopromazine for the emergency treatment of uncontrolled symptomatic hypertension in the pre-hospital setting. Methods: We reviewed data from 496 consecutive patients who received intravenous chlorpromazine as emergency therapy for uncontrolled symptomatic hypertension. Chlorpromazine was injected intravenously. The dose was 1 mg every 2-5 minutes until the systolic pressure was ≤140 mmHg and the diastolic pressure ≤100 mmHg with alleviation of symptoms. Results: The mean dose of chlorpromazine administered was 4.5 ± 5 mg (range 1-50 mg). Only 33 patients (7%) required >10 mg. Chlorpromazine reduced systolic BP from 222.82 ± 26.31 to 164.93 ± 22.66 mmHg (P < 0.001) and diastolic BP from 113.5 ± 16.63 to 85.83 ± 11.61 mmHg (P < 0.001). The sinus rate decreased from 97.9 ± 23.5 to 92.2 ± 19.7 beats per minute (P < 0.001). These results were achieved within the first 37 ± 11 minutes. Conclusions: Intravenous chlorpromazine is safe and effective when used as emergency treatment for uncontrolled symptomatic hypertension.