Morphine meperidine

Pharmacology Pentazocine, a potent analgesic, weakly antagonizes the effects of morphine, meperidine, and other opiates at the p-opioid receptor. 

Patients dependent on narcotics Patients dependent on narcotics may experience withdrawal symptoms upon the administration of nalbuphine. If unduly troublesome, control by slow IV administration of small increments of morphine until relief occurs. If the previous analgesic was morphine, meperidine, codeine or another narcotic... 

Opioids Tramadol, pethidine, oxycodone, morphine, meperidine... 

Like morphine, meperidine has an active metabolite, normeperidine, formed by A-demethylation of meperidine. Normeperidine is not analgesic but is a proconvulsant and a hallucinogenic agent. For this reason, meperidine use in patients with renal or fiver insufficiency is contraindicated because of the decreased clearance of the drug and its metabolite. Convulsant activity has been documented in elderly patients given meperidine and in patients using PCA who have decreased renal function. 

The dangers of dependency and addiction clearly preclude the use of such compounds as morphine, meperidine, and methadone as treatment for diarrhea. Antidiarrheal specificity therefore is of paramount importance in choosing among the synthetic opioids and their analogues (e.g., diphenoxylate and loperamide). 

II High Yes Codeine, morphine, meperidine Same as Schedule 1 (Demerol), opium poppy, opium tincture (Laudanum), granulated opium, powdered opium, raw opium, oxycodone (OxyContin, Percocet), thebaine... 

Ohqvist, G., Hallin, R., Gelinder, S., Lang, H., Samuelson, S. A comparison between morphine, meperidine and ketobemidone in continuous intravenous infusion for postoperative relief, Acta Anaesthesiol. Scand. 1991, 35, 44-48. 

Tramadol, pethidine, oxycodone, morphine, meperidine Buspirone, chlorpheniramine, dextromethorphan, linezolid, lithium, selegiline, tryptophan, St. John s wort... 

Opioid analgesics (see Chapter 14) are the primary medications used during PCA.9 Opioids such as morphine, meperidine, tramadol, fentanyl, and fentanyl... 

Meperidine shows certain relationships to both morphine and atropine in its action. Similar to morphine, it exerts a generalized depression of the CNS but, in ordinary doses, does not affect the cough reflex. Similar to morphine, it induces euphoria, and its continued use leads to tolerance and addiction. However, its euphoric and sedative effects are less than that of morphine addiction due to meperidine is more serious than that due to morphine. Meperidine is an effective analgesic,... 

Meperidine has replaced morphine to a large extent in medical practice because of the physician s reluctance to use an opiate and the belief that meperidine manifests less undesirable side effects than does morphine. However, both of these assumptions are ill founded. Addiction to meperidine is much less amenable to treatment than is addiction to morphine. Meperidine, similar to morphine and codeine, causes spasm of the upper gastrointestinal tract and typical attacks of biliary colic in biliary tract disease. Meperidine, in doses giving an equal analgesic effect, induces as much respiratory depression as does morphine. Similar to morphine, it also crosses the placental barrier and must therefore be used cautiously in the latter stages of labor. 

Naloxone (Narcan) and naltrexone hydrochloride (Trexan) reverse the respiratory depressant action of narcotics related to morphine, meperidine, and methadone. They differ from other narcotic analgesics in several respects. Naloxone does not cause respiratory depression, pupillary constriction, sedation, or analgesia. However, it does antagonize the actions of pentazocine. Naloxone neither antagonizes the respiratory depressant effects of barbiturates and other hypnotics nor aggravates their depressant effects on respiration. Similar to nalorphine, naloxone precipitates an abstinence syndrome when administered to patients addicted to opiate-like drugs. 

Another example of the largest common substructure search is shown in Fig. 6. Although they differ greatly in structure from one another, morphine, meperidine, and methadone exhibit similar pharmacological activities (analgesic properties). By the search with level (4) expression, two connected graphs are... 

Dubuisson, D., and Dennis, S. G. (1977). The formalin test A quantitative study of the analgesic effects of morphine, meperidine, and brain stem stimulation in rats and cats. Pain 4, 161—174. 

Actions Meperidine causes a depression of respiration similar to that of morphine, but there is no significant cardiovascular action when the drug is given orally. On intravenous (IV) administration, meperidine produces a decrease in peripheral resistance and an increase in peripheral blood flow, and may cause an increase in cardiac rate. As with morphine, meperidine dilates cerebral vessels, increases cerebrospinal fluid pressure, and contracts smooth muscle (the latter to a lesser extent than does morphine). In the gastrointestinal tract, meperidine impedes motility, and chronic use results in constipation. Meperidine does not cause pinpoint pupils, but rather causes the pupils to dilate because of an atropine-like activity. 

Therapeutic uses Meperidine provides analgesia for any type of severe pain. Unlike morphine, meperidine is not clinically useful in the treatment of diarrhea or cough. Meperidine produces less of an increase in urinary retention than does morphine. 

Pharmacokinetics Unlike morphine, meperidine is well absorbed from the gastrointestinal tract and is useful when an orally-administered, potent analgesic is needed. However, meperidine is most often administered intramuscularly. The drug has a duration of action of 2 to 4 hours, which is shorter than that of morphine (see Figure 14.6). Meperidine is N-demethylated in the liver and is excreted in the urine. [Note Because of its shorter action and dif-... 

The opioid agonists include morphine, meperidine, methadone, fentanyl, alfentanil, remifentanil and carfentanil. 

Full agonists morphine, meperidine, methadone, fentanyl, and heroin Partial agonists buprenorphine, codeine, propoxyphene Mixed agonist-antagonists nalbuphine, pentazocine Antagonists naloxone, naltrexone Phenothiazines chlorpromazine, fluphenazine, thioridazine Others haloperidol, clozapine, risperidone, olanzapine... 

Peak respiratory depression is observed within 1 hour of intramuscular administration, and there is a return toward normal starting in about 2 hours. Like other opioids, meperidine causes pupillary constriction, increases the sensitivity of the labyrinthine apparatus, and has effects on the secretion of pituitary hormones similar to those of morphine. Meperidine sometimes causes CNS excitation, characterized by tremors, muscle twitches, and seizures these effects are due largely to accumulation of a metabolite, normeperidine. As with morphine, respiratory depression is responsible for an accumulation of CO2 which, in turn, leads to cerebrovascular dilation, increased cerebral blood flow, and elevation of cerebrospinal fluid pressure. 

Naloxone, a pure narcotic antagonist (0.4 to 2.0 mg IV), is indicated for the complete or partial reversal of respiratory and CNS depression caused by naturally occurring and synthetic narcotics, including morphine, meperidine, methadone, nalbuphine, butorphanol, and pentazocine. 

IMPAIRED HEPATIC CLEARANCE OF DRUGS The effect of liver disease on the hepatic biotransformation of drugs cannot be predicted from any measure of hepatic function. Thus, even though the metabolism of some drugs is decreased with impaired hepatic function, there is no quantitative basis for dose adjustment other than assessment of the clinical response and plasma concentration. The oral bioavailability of drugs with extensive first-pass hepatic clearance (e.g., morphine, meperidine, midazolam, and nifedipine) may be increased in liver disease. 

W-Allylnormorphine does not antagonize the respiratory depression or the general central depression from the barbiturates. It is a specific antidote for morphine, meperidine, and methadone poisoning (Eckenhoff et al., 88). 

Euphoria and Addiction. About 200 mg. of meperidine in post-addicts are required to produce euphoria equivalent to that from 30 mg. of morphine. Meperidine, 200 mg., sharply reduced the intensity of abstinence phenomena after rvithdrawal from a daily dose of 300 mg. of morphine. Two hours after the meperidine, the intensity of the abstinence phenomena again increased to reach pre-meperidine levels in 10 hr. (90). 

It has a direct antagonistic effect against morphine, meperidine, methadone and levorphanol. 

Examples of Schedule II drugs are opiates and opioids (narcotics)—straight opiates of codeine, morphine, meperidine stimulants—amphetamine, methylphenidate depressants— amobarbital, pentobarbital, secobarbital, or any combination, that is, Tuinal hallucinogenic substances and any immediate precursors. 

The Meg X-chain dimer appears to have at least three distinct binding sites. One is located on the rim of the funnel-shaped cleft, a second is at the constriction between funnel and cavity, and a third is at the bottom of the cavity. These sites bind a whole range of compounds including -dansyl lysine, colchicine, 1,10-phenanthroline, methadone, morphine, meperidine, 5-acetyluracil, caffeine, theophylline, menadione, triacetin, and other compounds (Schiffer et al, 1973). 

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