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CAUTION: Federal law prohibits dispensing without prescription.
* Ok, Interpol is really not involved here, but for those of us outside the United States they know Demerol® as Pethidine, so there you go!
Meperidine hydrochloride (also known as pethidine outside the US) is a synthetic opiate agonist belonging to the phenylpiperidine class. Other members of this group include alfentanil, diphenoxylate, fentanyl, loperamide, and sufentanil. The chemical structure of meperidine is similar to local anesthetics. Meperidine is recommended for relief of moderate to severe acute pain and has the unique ability to interrupt postoperative shivering and shaking chills induced by amphotericin B. Meperidine has also been used for intravenous regional anesthesia, peripheral nerve blocks and intraarticular, epidural and spinal analgesia. A high incidence of side effects limits the utility of meperidine in these situations. According to the Agency for Health Care Policy and Research Clinical Practice Guideline for acute pain management in operative or medical procedures and trauma, meperidine is recommended only for use in very brief courses in patients who are healthy and/or have problems with other opiate agonists. Meperidine is considered a second-line agent for the treatment of acute pain. Meperidine is commonly underprescribed in terms of dose and interval. Meperidine is metabolized to normeperidine, a compound capable of inducing seizures at high concentrations. Meperidine is not recommended for the treatment of chronic pain because of the risk of seizures with repetitive dosing and its short duration of action. Meperidine is often used as a rescue medication for treatment of Migraine, meaning used for controlling severe Migraine when a Migraineur dose not respond to abortive treatments or the Migraineur cannot use effective abortive regimes when they are contraindicated. Meperidine is available in both oral and parenteral forms and was approved by the FDA and marketed in 1942.
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 include µ (mu), kappa (kappa), and delta (delta), which have been reclassified by an International Union of Pharmacology subcommittee as OP1 (delta), OP2 (kappa), and OP3 (µ). These receptors are coupled with G-protein (guanine-nucleotide-binding protein) receptors and function as modulators, both positive and negative, of synaptic transmission via G-proteins that activate effector proteins. Opioid-G-protein systems include adenylyl cyclase-cyclic adenosine monophosphate (cAMP) and phospholipase3 C (PLC)-inositol 1,4,5 triphosphate (Ins(1,4,5)P3)-Ca).
Meperidine is administered via the oral or parenteral routes. When administered orally, it undergoes extensive first-pass metabolism. Oral bioavailability increases to 8090% in patients with hepatic impairment, compared with 5060% in patients with normal hepatic function. Meperidine is less than one-half as effective when given orally as opposed to parenterally and it is recommended not to give meperidine via this route. After oral administration the onset of analgesia is within 15 minutes and peak effects occur in 6090 minutes. Following subcutaneous or IM administration, onset of analgesia occurs within 1015 minutes and peak effects occur within 1 hour. When given intravenously, the onset of analgesia is noted within 1 minute and the time to peak effects is 57 minutes. The duration of meperidine-induced analgesia is 24 hours but this decreases with chronic dosing. Protein binding is 6575%, primarily to albumin and alpha-1-acid glycoprotein. Meperidine is distributed widely, and it crosses the placenta and distributes into breast milk.
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