Poisoning, overdose, antidotes

Deliberate and accidental self poisoning Principles of treatment Poison-specific measures General measures 

Specific poisonings cyanide, methanol, ethylene glycol, hydrocarbons, volatile solvents, heavy metals, herbicides and pesticides, biological substances (overdose of medicinal drugs is dealt with under individual agents) 

Accidental self-poisoning causing admission to hospital occurs predominantly amongst children under 5 years, usually with medicines left within their reach or with domestic chemicals, e.g. bleach, detergents. 

Successful treatment of acute poisoning depends on a combination of speed and common sense, as well as on the nature of the poison, the amount taken and the time which has since elapsed. The majority of those admitted to hospital require only observation and medical and nursing supportive measures 

Activated charcoal, although unpalatable, appears to be relatively safe but constipation or mechanical bowel obstruction may be caused by repeated use. Aspiration of charcoal into the lungs can cause hypoxia through obstruction and arteriovenous shunting. Charcoal adsorbs and thus inactivates 

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Overdosing Antidotes are almost poisons in their own right, and anyone overdosing on them suffers the effects of the poison the antidote is designed to cure. 

List of Substances with a General Overview of Prehospital Treatment and Specific Antidotes for Poisoning and Overdose... 

Atropine is used as an antidote in poisoning by an overdose of a cholinesterase inhibitor (see Chapter 14). It also is used in cases of poisoning from species of mushroom that contain high concentrations of muscarine and related alkaloids (e.g., Clitocybe dealbata). 

Pralidoxime Very high affinity for phosphorus atom but does not enter CNS Regenerates active AChE can relieve skeletal muscle end plate block Usual antidote for early-stage (48 h) cholinesterase inhibitor poisoning Intravenous every 4-6 h Toxicity Can cause muscle weakness in overdose... 

Antidote Antidotes are used to negate the effects of or reduce the effective intensity of poisons or other various toxins. Antidotes by their very nature are poisons themselves and can cause damage to those that overdose on them. This type of drag or chemical agent grants the user a +4 bonus on his next save against the appropriate type of poison. 

If it is known which chemical the patient has taken, an antidote can be given if one is available, as for example with paracetamol (see pp. 53-4). Whether an antidote is used will depend on whether the overdose is at a dangerous level. Antidotes have been used (not always successfully) for centuries and one of the earliest mentions is in Homer s Odyssey, where it is suggested that Odysseus take moly (possibly snowdrop) to protect himself against the poison of Circe. Apparently, in ancient China around 2000 BC antidotes were tried experimentally. 

Can toxicity due to an overdose of heroin be treated The answer is yes, because understanding how the drug acts, by binding to specific receptors, allows treatment of poisoning to be carried out logically by using an antidote. The antidote used is normally naloxone. 

Digoxin Immune Fab (Protherics) Poison antidote, digoxin overdose... 

From prospective data (74,77), it has been estimated that around 58 000 people take paracetamol in overdose each year in England and Wales and that these episodes of poisoning prompted 3.3% of inquiries to US regional poisons centers (78), 10% of inquiries to the UK National Poisons Information Service (79), and up to 43% of all admissions to hospital with self-poisoning in the UK (80). Despite the availability of effective antidotes for patients who seek medical intervention early after an overdose, in the USA paracetamol alone accounted for 4.1% of deaths from poisoning reported to American poison centers in 1997 (78). 

Poisoning emergencies are a common occurrence. In 2002, The Toxic Exposure Surveillance System of the American Association of Poison Control Centers reported 2 380028 toxic exposures and 1153 resultant fatalities. Of these total exposures, 548 093 (22.2%) were managed in a healthcare facility and 72 877 were admitted to a critical care unit (3.1%). The mortality rate associated with these overdose patients was less than 1%. Thorough evaluation, adequate supportive care, and the use of a few specific antidotes have resulted in lowered morbidity and mortality if the poisoned patient arrives at the hospital in time for the healthcare team to intervene. In select cases, decreasing further toxin absorption by various decontamination procedures may be of benefit. 

TREATMENT OF LITHIUM INTOXICATION There is no specific antidote for LG intoxication, and treatment is supportive. Vomiting induced by rapidly rising plasma LL may tend to limit absorption, but fatalities have occurred. Care must be taken to assure that the patient is not Na - and water-depleted. Dialysis is the most effective means of removing the ion from the body and is necessary in severe poisonings, i.e., in patients exhibiting symptoms of toxicity or patients with serum LG concentrations >4 mEq/L in acute overdoses or >1.5 mEq/L in chronic overdoses. 

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