MEPERIDINE BY GC/MS, URINE
- MEPERIDINE BY GC/MS, URINE
- Start Date
- Expiration Date
- Demerol; Pethidine hydrochloride
- CPT Codes
- Reference Test
- Transport Info
- Fasting Required?
- Patient Instructions
- Reference Range
Negative (less than assay limit of detection)
Gas Chromatography/Mass Spectrometry (GC/MS)
Confirm positive screen results by an alternate, specific method; detect use.
Meperidine (pethidine hydrochloride or Demerol) is a synthetic narcotic analgesic, introduced in the 1930’s. It is a schedule II drug under the Controlled Substances Act and, after morphine and codeine, is the most widely used narcotic analgesic with 1/6 to 1/8 the analgesic potency of morphine.The drug is used for relief of moderate to severe pain, as a preoperative medication, for support of anesthesia and for obstetrical analgesia. The usual therapeutic dose in adults is 50-150 mg every 3-4 hours. Intramuscular administration is preferred when repeated doses are necessary, although subcutaneous injection is acceptable for occasional use. Oral administration is less effective due to extensive first pass metabolism.The main pharmacological effects of meperidine are on the central nervous system. Therapeutic doses cause analgesia, sedation, euphoria, respiratory depression and other clinical actions similar to morphine. The onset of action is slightly more rapid and the duration of action is slightly shorter than morphine.In normal individuals, about 70% of a dose of meperidine is excreted within 24 hours. Approximately 7-10% of the dose is excreted unchanged in the urine, with 10-15% as normeperidine and the rest as meperidinic acid, normeperidinic acid and their conjugates and several minor metabolites.Normeperidine is the only active metabolite with about half the analgesic activity of meperidine and twice the convulsant activity. However, it is 2-3 times more toxic than the parent drug and has a half-life of 14-30 hours. Generally, normeperidine is not found after a single therapeutic administration but will accumulate with repeated or large doses and in patient with renal failure.Meperidine crosses the placenta. The half-life in neonates is 22-23 hours, with mean cord blood concentrations at delivery of 75-91% of the maternal concentrations.Repeated use of meperidine may cause physical and psychological dependence and tolerance. It is thought to be a leading drug of abuse among medical and allied health professionals.The presence of meperidine in urine indicates exposure to the drug and does not necessarily indicate impairment.