Domperidone works by speeding up the passage of food through the stomach into the intestine, which then prevents nausea and vomiting. It also prevents food from flowing the wrong way through the stomach and so can prevent reflux. Domperidone blocks dopamine receptors found in an area of the brain known as the chemoreceptor trigger zone (CTZ). The CTZ is activated by nerve messages from the stomach when an irritant is present or when certain chemicals are in the blood stream, such as pregnancy hormones. Once activated, messages are sent to the vomiting centre which sends messages to the gut and triggers vomiting. By blocking the dopamine receptors in the CTZ, domperidone prevents nausea messages from being sent to the vomiting centre and in turn reduces the nausea and vomiting.
As with many of the treatments mentioned here, the safety of Domperidone has not been established in proper medical trials. It has, however, been used for a number of years in pregnancy and as yet no adverse effect on the foetus has been reported. As with all these treatments, their use should be restricted to cases where first line treatment has failed to suppress symptoms and the benefits of further treatment would outweigh the risks to the foetus.
Domperidone can be given as a suppository (in your back passage) which some women may find easier then swallowing orally.