Opiate antagonists overdose

In overdose, managing respiration is essential. Opiate antagonists may be used, but can provoke... 

Stelman GS, Woerpel RW, Sherard ES. Treatment of accidental sodium valproate overdose with an opiate antagonist [Letter]. Ann Neurol 1979 6 274. 

Naloxone is an opiate antagonist which is used as an antidote to opiate overdoses. It has also been used in withdrawal programs, for babies born to addicted mothers, and in the study of the body s natural opiates, the endorphins and enkephalins. 

Overdoses of morphine resulting in unconsciousness can be rapidly reversed with the opiate antagonist naloxone (Narcan). Given by intravenous injection, naloxone works in a minute or two by occupying the opiate receptors in the brain, without any action of its own other than to block morphine or other opioids. A dose of 0.4-0.8 mg (to a maximum of 10 mg) is given every three to five minutes to revive an overdosed person. 

Opioid antagonists (Table 7.4), predominantly naloxone, are used clinically to reverse the effects of opiates in overdose or postoperative sedation. Naltrexone, which has oral bioavailability, is used for the treatment of narcotic addiction and alcohol dependence. As discussed below (Section 2.2.2.1), peripherally selective antagonists are being evaluated for treatment of constipation and other gastrointestinal side effects associated with opioid agonist use. 

Opiates are used clinically because of their analgesic properties. Opiates also cause sedation, euphoria, respiratory depression, orthostatic hypotension, diminished intestinal motility, nausea, and vomiting. The major manifestations of morphine overdose are coma, miosis (pinpoint pupils), and respiratory depression. Pulmonary edema often is a complication of morphine overdose, and death may result from cardiopulmonary arrest. Treatment for morphine overdose includes administration of the opiate antagonist naloxone (Narcan), which dramatically reverses the effects of morphine. 

Which opiate antagonist is most likely to be used to treat symptoms of opioid overdose in a nonaddicted patient receiving analgesic therapy ... 

Opiate overdose is a medical emergency that can result in respiratory and CNS depression. The opioid receptor antagonist naloxone immediately reverses cardiorespiratory depression. However, repeated naloxone administration is required, since the effects of naloxone last for 30 min, while opioid agonists can remain at potentially lethal blood levels for several hours. 

Only one antagonist is known, naloxone, which is used clinically to treat opiate overdoses and, experimentally, to investigate whether physiological or biochemical actions are opiate-mediated. One example of its use is to support the hypothesis that P-endorphin is responsible for the analgesic effects of acupuncture. Not only does low frequency electroacupuncture increase p-endorphin levels in cerebrospinal fluid but naloxone nullifies the analgesic effect of this treatment. 

It is worth mentioning that iV-allylic substitution in a number of morphine derivatives, as a rule, leads to antagonistic properties. Naloxone is a few times stronger than nalorphine as an antagonist. It blocks opiate receptors. It eliminates central and peripheral action of opioids, including respiratory depression. Naloxone is used upon overdose of narcotic analgesics.Synonyms for this drug are narkan, talwin, and others. 

NALOXONE A short-acting narcotic antagonist that binds to opiate receptors and blocks them. Used to treat opiate overdose. 

Q4 Yes. Rob has used both atropine and phenylephrine this afternoon. Muscarinic antagonists such as atropine, tropicamide and cyclopentolate cause dilation of the pupils. The a-adrenoceptor agonists, such as phenylephrine, also produce my driasis. Mydriasis may cause acute closed-angle glaucoma in some patients. It is unlikely that a very small amount of cocaine in the eye would cause problems, but in cocaine overdose pupils become widely dilated. This is due to blockade of uptake 1, a process normally involved in terminating the effects of noradrenaline. In the presence of cocaine the effects of sympathetic stimulation on the eye would be prolonged and the pupil would dilate. Morphine causes constriction of the pupils via opiate receptors. 

The 17 - N- a 11 y I - (n a I o x o n e. 3a) and 17 - /V-c v c lop I opv I m e t h v I (naltrexone, 3b) analogues of oxymorphone (2d) are the prototype opioid receptor antagonists with some selectivity for MOR. They have entered clinical practice as treatments for narcotic overdose (naloxone) and alcoholism or opioid abuse/dependence (naltrexone). The 17-quatemary derivative of naltrexone, methylnaltrexone (4) has recently been introduced into clinical practice as a treatment for opiate-induced bowel dysfunction [1],... 

Abuse of psychoactive chemicals can result in neurotoxic effects that are difficult to treat medically. Successful therapy is often hindered by the lack of useful antagonists for many of these chemicals and by the extensive distribution of these chemicals out of the bloodstream. Although there are treatments for opiate addiction and an antagonist for opiate overdose, there are no such medical treatments for most drugs of abuse such as phencyclidine (PCP) and cocaine. Therefore, this chapter focuses on recent advances in immunotherapy which suggest this novel approach could be beneficial in the treatment of drug abuse. 

TREATMENT OF OPIOID OVERDOSAGE Naloxone hydrochloride should be used cautiously for opiate overdose because it also can precipitate withdrawal in dependent subjects and cause undesirable cardiovascular side effects. By carefully titrating the dose of naloxone, it usually is possible to antagonize the respiratory-depressant actions without eliciting a full withdrawal syndrome. The duration of action of naloxone is relatively short, and it often must be given repeatedly or by continuous infusion. Opioid antagonists also have been employed effectively to decrease neonatal respiratory depression secondary to the intravenous or intramuscular administration of opioids to the mother. In the neonate, the initial dose is 10 /ig/kg given intravenously, intramuscularly, or subcutaneously. 

Narcotic antagonists (see chart) are antidotes for overdoses of narcotic analgesics. They have a higher affinity to the opiate receptor site than the narcotic analgesic and block the narcotic analgesic from binding to the opiate receptor site. They also reverse the respiratory and CNS depression caused by the narcotics. 

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