2837 Meperidine A narcotic analgesic that can be used for the relief of most types of moderate to severe pain, including postoperative pain and the pain of labor. Prolonged use may lead to dependence of the morphine type; withdrawal symptoms appear more rapidly than with morphine and are of shorter duration. 57-42-1 4058 C15H21NO2 247.157230 White powder. 270°C 3220 mg/L (at 30°C) Intravenous; oral; parenteral (intramuscular). The oral bioavailability of meperidine in patients with normal hepatic function is 50-60% due to extensive first-pass metabolism. Bioavailability increases to 80-90% in patients with hepatic impairment (e.g. liver cirrhosis). Meperidine is less than half as effective when administered orally compared to parenteral administration. One study reported that 80-85% of the drug administered intramuscularly was absorbed within 6 hours of intragluteal injection in health adults; however, inter-individual variation and patient-specific variable appear to cause considerable variations in absorption upon IM injection. Meperidine is primarily a kappa-opiate receptor agonist and also has local anesthetic effects. Meperidine has more affinity for the kappa-receptor than morphine. Opiate receptors are coupled with G-protein receptors and function as both positive and negative regulators of synaptic transmission via G-proteins that activate effector proteins. Binding of the opiate stimulates the exchange of GTP for GDP on the G-protein complex. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine and noradrenaline is inhibited. Opioids also inhibit the release of vasopressin, somatostatin, insulin and glucagon. Opioids close N-type voltage-operated calcium channels (OP2-receptor agonist) and open calcium-dependent inwardly rectifying potassium channels (OP3 and OP1 receptor agonist). This results in hyperpolarization and reduced neuronal excitability. Meperidine is metabolized in the liver by hydrolysis to meperidinic acid followed by partial conjugation with glucuronic acid. Meperidine also undergoes N-demethylation to normeperidine, which then undergoes hydrolysis and partial conjugation. Normeperidine is about half as potent as meperidine, but it has twice the CNS stimulation effects. Route of Elimination: Excreted in the urine. The proportion of drug that is excreted unchanged or as metabolites is dependent on pH. When urine pH is uncontrolled, 5-30% of the meperidine dose is excreted as normeperidine and approximately 5% is excreted unchanged. Meperidine and normeperidine are found in acidic urine, while the free and conjugated forms of meperidinic and normperidinic acids are found in alkaline urine. Half Life: Initial distribution phase (t_{1/2 α}) = 2-11 minutes; terminal elimination phase (t_{1/2 β}) = 3-5 hours. In patients with hepatic dysfunction (e.g. liver cirrhosis or active viral hepatitis) the t_{1/2 β} is prolonged to 7-11 hours. No indication of carcinogenicity to humans (not listed by IARC). Used to control moderate to severe pain. Medical problems can include congested lungs, liver disease, tetanus, infection of the heart valves, skin abscesses, anemia and pneumonia. Death can occur from overdose. Primary attention should be given to the reestablishment of adequate respiratory exchange through provision of a patent airway and institution of assisted or controlled ventilation. The narcotic antagonist, naloxone hydrochloride, is a specific antidote against respiratory depression which may result from overdosage or unusual sensitivity to narcotics, including meperidine. Therefore, an appropriate dose of this antagonist should be administered, preferably by the intravenous route, simultaneously with efforts at respiratory resuscitation. An antagonist should not be administered in the absence of clinically significant respiratory or cardiovascular depression. Oxygen, intravenous fluids, vasopressors, and other supportive measures should be employed as indicated. In cases of overdosage with Meperidine tablets, the stomach should be evacuated by emesis or gastric lavage. (L1712) 2009-07-21T20:26:56Z 2026-03-31T17:48:32Z Meperidine C07128 122528 Meperidine DB00454 true CCOC(=O)C1(CCN(C)CC1)C1=CC=CC=C1 C15H21NO2 InChI=1S/C15H21NO2/c1-3-18-14(17)15(9-11-16(2)12-10-15)13-7-5-4-6-8-13/h4-8H,3,9-12H2,1-2H3 XADCESSVHJOZHK-UHFFFAOYSA-N 247.3327 247.157228921 Exogenous Solid 2.72 HMDB14597 CHEMBL607 3918 CHEM002197 DTXSID9023253 NS00009544 ethyl 1-methyl-4-phenylpiperidine-4-carboxylate