Oxytocin may enhance the vasopressor effects of sympathomimetics. Some inhalational anaesthetics, such as cyclopropane or halothane, may enhance the hypotensive effect of oxytocin and reduce its oxytocic effect, cardiac arrhythmias may occur. Prostaglandins and oxytocin may potentiate the effects of each other on the uterus; the UK licensed product information for oxytocin states that it should not be started for 6 hours after use of vaginal prostaglandins.