"The dose makes the poison" is one of the basic principles of toxicology, it refers to the relationship between dose and toxicity. This principle is not only used drugs, but also used in all of the chemical composition, and even water and oxygen, if you drink too much, eat too much or breathe too much, then people will be poisoned.
For vitamin C, for example. The body can not store vitamin C, so regularly supplement daily requirement of vitamin C is 75 mg to 90 mg of vitamin C poisoning is 2000 mg, can cause nausea, vomiting, and other heartburn, abdominal discomfort and headache. From food intake is not possible to toxic doses of vitamin C, so for vitamin C by eating people, vitamin C is a very safe dietary ingredient. However, there is a theory that vitamin C can prevent colds and cancer, need 5-10 grams per day, can only rely on vitamin C supplements to achieve. This theory does not clinical evidence but because it exceeds the amount of poisoning caused by a lot of side effects. Do not say such a large amount of vitamin C intake unfounded, even if there is a certain effect, to take much more than a dose of the toxic dose to achieve the purpose of prevention and treatment, itself more harm than good.
Vitamin C is a nutrient, but also drugs, under normal circumstances, nutritional and therapeutic doses of vitamin C dose of live very far away, in some cases their toxic doses, there would be no problem, and therefore will not be rare Side effects while avoiding the use of vitamin C.
On drug toxicity have a misconception, does not mean someone poisoned a drug problem, in many people's minds have to eat as long as the situation appeared toxic drugs be considered toxic, otherwise all vary. This incorrect understanding is one of the main reasons many toxic side effects of drugs on the Chinese drug market, especially in medicine.
Because there are individual differences, unless with a huge dose, no one thing can make everyone or all of the test animals poisoning. In 1927, after the median lethal dose (LD50) of the emergence of the concept has been used as an indicator of acute toxicity. LD50 is carrying out large-scale animal experiments, half the dose causing the death of animals tested. This dose is body weight in kilograms for the body but also according to the weight calculation. Most LD50 in rats is obtained, and a few from other animals such as mice, but also directly from the people, because people sensitive than animals. For example, if you eat cantharidin, then human LD50 is 0.5 mg / kg, the most sensitive animal is a horse, LD50 of 1 mg / kg. Further weight multiplied by the amount is not necessarily LD50 lethal dose, or to cantharidin, for example, 20 kg LD50 is 10 mg may be lethal dose has been reached.
Each drug has its average treatment dose, mean dose of most drugs and LD50 very far, so it is safe, but there are a few very close between the two drugs, such as digoxin, in the course of these drugs must be strictly observed . Modern pharmaceutical industry research and development of new drugs, the laboratory developed thousands of new drugs can ultimately only one listed, due to its effective dose exceeds its LD50, before two clinical trials is to detect drug safety, and thereafter to examine its effectiveness.
LD50 is not the same for each drug may be very different from each other, so there is no dose smaller, less toxicity said. But to be specific to each medication. Some drugs take a big dose no problem, some small doses of the drug will produce toxicity.
Medication must be prescribed by a doctor, not because the dose is small and increase the amount of their own, perhaps because little space mean that the drug dose and LD50 between, before approaching the LD50, there may be a variety of side effects. Unless certain specific circumstances, security must always be on medication first.
Baidu know without a daily newspaper written permission, any units and individuals shall not in any way or reason to know that Baidu content published daily use, copy, modify, copied, transmitted, or bundled with other products use, sale. Where the infringement of intellectual property Baidu know daily, it will pursue its legal responsibility according to the law. Application for authorization and commercial cooperation please contact zhidaoribao@baidu.com
Article Source: Baidu know daily (http://zhidao.baidu.com/daily)
Original link: http: //zhidao.baidu.com/daily/view id = 585?