Why are meperidine and promethizine prescribed together is it okay to only take meperidine?

Ancient wisdom. In medical school, we were taught to combine Demerol (meperidine hydrochloride) and Promethazine because they provided better acute pain relief. There is nothing wrong with Meperidine (demerol) for short-term treatment, however metabolic products of this medicine causes damage in the long run. Keep in mind, this combination came at emergency rooms. Combining an opiate with a safe sedative gets people out of the er.
Pain killer causes n. Meperidin is a narcotic pain killer which can cause nausea and vomiting and Promethazine is an antiemetic which stops the feeling of nausea and vomiting yes you can take meperidin alone if you can tolerate it.