The nurse has administered promethazine intravenously to a client in active labor. the drug has had the desired effect when the nurse notes:

When the client is experiencing decreased nausea and vomiting, then the medication is doing what it is supposed to. Promethazine is an antihistamine and a sedative and, as such, is used to calm down the responses to nausea that can occur during stressful events such as labor.