MORTALITY FROM POISONING
This varies from country to country depending on the kind of poisons encountered, the extent of awareness about poisoning, the availability of treatment facilities, and presence or absence of qualified personnel. While in developed countries the rate of mortality from poisoning is as low as 1 to 2%, in India it varies from a shocking 15 to 35%. Children under 15 years of age account for most cases of accidental poisoning, but fortunately they are associated with relatively low mortality. On the other hand, most suicidal exposures are seen in individuals over 15 years of age but are associated with high mortality.
In poisoning cases, the attending physician is often asked to comment on the prognosis of the victim’s condition. Unfortunately in cases of serious poisoning, it is very difficult to predict the outcome. There are many reasons for this. In a substantial number of cases, the doctor is unaware of the exact nature of the poison consumed; in others, the victim may have ingested several kinds of drugs simultaneously. Even in those cases where the exact identity and dose of a single ingested poison is known, the doctor may not have a clear idea as to its toxicity. In order to ameliorate the situation to some extent and help physicians have some idea as to the hazardous nature of various poisons, a system of “toxicityrating” has been evolved for common poisons. The higher thetoxicity rating for a particular substance (over a range from 1 to 6), the greater its potency (Table 1.1). The rating is based on mortality, and is applicable only to the acute toxicity of a single dose taken orally. In the case of commercial products where various combi-nations of poisonous substances may have been used, one has to derive an estimate of the toxicity rating in totality, taking into consideration all the components put together, with particular reference to individual concentrations.
To assess and rate the toxicity of a drug, the Usual FatalDose (UFD) is taken into consideration which is derived fromanimal experimental data and statistics of human poisoning. The UFD is based on the Minimum Lethal Dose (MLD) which is usually indicative of the lethal dose that is fatal to 50% of animals (LD 50).
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