How long does promethazine stay in your system depends on what form it comes in. The dosage and how it’s taken also affects how long it remains in your body. For example, a liquid is usually taken in smaller doses than tablets or capsules. Follow the instructions on the bottle or ask your doctor if you’re unsure about how to take it.
This medication prevents the release of a natural substance in your body called histamine. It can help prevent and treat certain types of nausea and vomiting, such as after surgery or motion sickness. It can also be used to make you sleepy or relaxed before and after surgery. It is also an allergy medicine and can relieve runny nose and itching caused by common cold symptoms. It can also reduce pain by reducing stimulation of certain parts of the brain.
It is possible to overdose on promethazine. Overdose can cause severe side effects including seizures and severely low blood pressure. For this reason, it is important to only use this medicine as prescribed by your doctor.
Do not drink alcohol while taking this medication. It can make the drowsiness from this medicine more extreme and last longer. This can be dangerous for children and adults. Tell your doctor if you have: a history of angle-closure glaucoma (increased pressure in the eyes); liver or kidney disease; any condition that causes trouble urinating, such as an enlarged prostate; heart problems; or asthma.