Opiate overdose

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. 

I hebaine (46) Naloxone (48) Benzyltetrahydro-isoquinoline alkaloid Antidote for opiate overdose... 

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. 

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

Opiate addiction has also helped spread diseases, such as the human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and tuberculosis among addicts who inject the opiate drugs and share dirty needles. The rate of opiate-associated emergency hospital visits in recent years has significantly increased. Furthermore, the number of deaths related to those opiate overdoses has almost doubled in this period. All of these trends point to the significant social costs associated with opiate abuse in the United States. 

The other mental effects of morphine take place at the arousal centers of the brain, in the brainstem, to produce a sleepiness and relaxation. However, some patients experience restlessness instead of drowsiness, with increased limb movement rather than relaxation. Confusion and slurred speech almost always accompany morphine at higher doses. Meanwhile, the so-called pinpoint pupils of opiate overdose are created by morphine s action on the iris, resulting in blurred vision and impaired ability to see in the dark. 

Man L-H, Best D, Gossop M, Stillwell G, Strang J. Relationship between prescribing and risk of opiate overdose among drug users in and out of maintenance treatment. Eur Addiction Res 2004 10 35-40. 

Dettmer K, Saunders B, Strang J. Take home naloxone and the prevention of deaths from opiate overdose two pilot schemes. BMJ 2001 322(7291) 895-6. 

Opiates are widely used all over the world, but recently concerns about opiate use (and deaths from such use) have increased in Australia and the UK (45). The rate of opiate overdose deaths in these countries increased dramatically between 1985 and 1995. Throughout that period, it was four to ten times higher in Austraha than the UK, but the rate of increase may have been greater in the UK in the latter half of the period, since the difference in rate narrowed substantially during that time. Methadone maintenance treatment, estabhshed in Australia in 1969 and in the UK in 1970, has become the main treatment for opiate dependence in both countries. About half of the opiate deaths in the UK were attributed at least in part to methadone. By contrast, considerably fewer (18%) opiate overdose deaths in Austraha were attributed to methadone. The authors suggested that the discrepancy in the rates between the two countries could be artefacts of the differences in (a) the documentation of these deaths, (b) the rate of opiate dependence, (c) the route of opiate administration, (d) opiate purity, and, most importantly, (e) the method of delivery of methadone maintenance treatment. 

Scherrer P, Delaloye-Bischof A, Turin G, Perret C. Participation myocardique a la rhabdomyolyse non traumatique apres surdosage aux opiates. [Myocardial involvement in nontraumatic rhabdomyolysis following an opiate overdose.] Schweiz Med Wochenschr 1985 115(34) 1166-70... 

Cook S, Moeschler O, and Michaud K (1998) Acute opiate overdose Characteristics of 190 consecutive cases. Addiction 93 1559-1565. 

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. 

Pinpoint pupils opiate overdose (treatment = naloxone)... 

There is in inverse relationship between manifestation of opiate-induced respiratory depression and the degree of pain stimulus present. Thus, when analgesic effects decrease the pain stimulus at high doses, respiratory depression may suddenly be manifested. In the same way, respiratory depression induced by opiate overdose may be delayed by the induction of a painful stimulus. 

What is a simple diagnostic procedure for the determination of opiate overdose ... 

Nalmefene, a derivative of naltrexone, is used in therapy of opiate overdose. 

No. They are essentially inert. This allows the drugs to be used in diagnosis of opiate overdose without fear of systemic disruption. 

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. 

If there is still no response and opiate overdose is highly suspected by history or clinical presentation (pinpoint pupils, apnea, or hypotension), give naloxone, 10-20 mg IV. 

Take-home message Further reading Chapter 66 Opiate Overdose Preparation... 

Don t keep Chrissie waitii - if withdrawn, she ll become increasii ly uncomfortable and frustrated. Attend swiftly if you suspect alcohol or GBL withdrawal, as these can be fatal. Only prescribe opiate substitutes if clear evidence of dependence opiate withdrawal is unpleasant, but opiate overdose kills. Polysubstance misuse is veiy common don t hesitate to seek specialist advice, especially riien multiple drugs are involved. 

Opiate overdose is a medical emei ency. Always transfer to ED. 

Check for signs of opiate overdose, and if unsure, administer a trial of naloxone. 

Strang J, Powis B, Best D, Vingoe L, Griffiths P, Taylor C, et al. Preventing opiate overdose fatalities with take-home naloxone pre-launch study of possible impact and acceptability. Addiction February 1999 94(2) 199-204. 

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