Use

For therapeutic monitoring only (not for forensic purposes). Meperidine, a phenylpiperidine derivative, is a synthetic opioid analgesic. Many of its pharmacologic properties and indications are similar to those of morphine, but meperidine has no effect on cough and is much less constipating. It is 1/8 as potent as morphine on a weight basis when administered parenterally. Meperidine is about 1/3 to 1/4 as potent orally as parenterally.