Promethazine is used in the treatment of nausea, vomiting, allergic conditions and motion sickness. It is also used for short-term treatment of insomnia (difficulty sleeping) in adults and as a sedative in children aged 5 years and above.

Promethazine is an antiallergic medication. When your body is exposed to an allergen (pollen, animal dander, house dust etc.), it produces a chemical called histamine. This causes watery eyes, runny or blocked nose, sneezing, skin rashes, itching etc. Promethazine works by blocking the action of histamine, thereby relieving these symptoms. It also works directly on several areas of the brain to prevent nausea/vomiting and help you feel more relaxed.