Sunday, May 29, 2011

Opioid analgesics : Overdose

Intentional (when a suicide attempt) or unintentionally (when mispricing force drug) receiving high doses of opioids leads to intoxication or overdose syndrome, the risk of death. Any opioid or opioid analgesic can cause intoxication, but the most dangerous powerful drugs such as fentanyl (80-100 times stronger than morphine).
For a typical intoxication, which develops immediately after I / overdose, characterized by the following: shortness of breath with a frequency of 2-4 per minute, miosis (rolling in mydriasis with the development of hypoxia of the brain), bradycardia, hypothermia, lack of reaction to external stimuli. In the absence of an emergency develops cyanosis, and death occurs due to the cessation of breathing and circulation. Findings at autopsy are scarce, except for diffuse brain edema. It is also possible anaphylactoid reactions to intravenous heroin, at least partly due to impurities, such reactions are typical lethargy, alveolar pulmonary edema, eosinophilia.
The primary measure for any overdose - maintaining vital functions by means of mechanical ventilation and other emergency measures. A radical method of treatment of opioid overdose - in / or / m opiate receptor blocker naloxone in an initial dose of 0.2 mg (0,5 ml vials of 10 ml) and more. In the absence of the effect of the injection can be repeated in 3-10 minutes. Dose choose, focusing on the patient's condition. Since naloxone acts only 2-3 h, the observation period should be not less than 24 hours after an overdose of heroin and 72 hours after an overdose of a long-acting drug such as methadone. If the effect of naloxone is insignificant, should be suspected concomitant overdose of benzodiazepines, in which case it is possible to test flumazenilom (0,2-0,5 mg / min up to maximum total dose of 3 mg). In many patients with opioid analgesic depedence, physical 2-8 h after injection of naloxone rapidly developing withdrawal symptoms, but to a complete stabilization of vital functions of intensive therapy of this syndrome is not justified.
Treatment as typical of intoxication, and anaphylactoid reactions often requires continuous maintenance of vital functions as long as the toxic substance will not be completely eliminated. May require mechanical ventilation (with anaphylactoid reactions - with increased F1O2), infusion therapy in combination with pressor agents to maintain blood pressure, gastric lavage to remove residual drug (if the patient is unconscious, you should use an endotracheal tube cuff to prevent aspiration of gastric contents) . It is also necessary treatment of arrhythmias and seizures, especially characteristic of an overdose of codeine, dextropropoxyphene, and pethidine.

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