Some circulatory and respiratory effects of morphine in patients without pre-existing cardiac disease

Haemodynamic and respiratory effects of i.v. morphine (10 mg/70kg body weight) were studied in 10 adults with unimpaired circulatory function. There were significant changes in mean arterial pressure, mean heart rate, respiratory rate and tidal volume, at 10-, 30- and 60-min intervals. Transient changes in mean total systemic resistance and mean stroke volume were also seen at 10 min. The results strongly suggest a peripheral vasodilator response to morphine. Respiratory depression was not demonstrated.