Adverse reactions are the physical discomfort that may occur after using the drug, such as dizziness, nausea, vomiting, rash and even changes in blood routine, abnormalities in liver and kidney functions, etc. It also specifies which mild symptoms can be relieved on their own, under what circumstances the drug should be consulted at a hospital or even discontinued, and which laboratory indicators should be checked regularly during the use of the drug. Due to the existence of individual differences, each person’s reaction after the use of drugs are different. Careful reading of these instructions when using drugs can reduce panic, timely detection of problems, timely discontinuation of drugs or take relevant measures to reduce the damage to the organism. It should be reminded that the adverse reactions of some drugs can be reduced or avoided by other drugs. As we all know, tumor chemotherapy has obvious toxic side effects, for example, paclitaxel is a common chemotherapy drug used in a variety of solid tumors, and a common adverse reaction is numbness of the limbs, but if you can take oral Chinese medicine to regulate it at the same time, it can be significantly reduced or completely relieved. Cao Wenlan, Department of Oncology, Xiyuan Hospital, Chinese Academy of Traditional Chinese Medicine, prohibits, cautions, contraindicates or follows medical advice “prohibit”, that is, prohibits the use of all drugs that are prohibited, must strictly implement the provisions of the drug description, such as patients allergic to penicillin or cephalosporin antibiotics, is absolutely not used, otherwise it will endanger life. Some drugs also prohibit the use of specific groups of people, such as morphine can inhibit the respiratory center, bronchial asthma and pulmonary heart patients should be prohibited, otherwise it will pose a serious danger to the human body, or even life-threatening. “Caution” refers to the application of drugs to be cautious, but not absolutely can not be applied, need to be carefully considered, weigh the pros and cons, in the case of benefits outweigh the disadvantages before use, preferably under the guidance of a physician, and must be closely observed in the process of medication for adverse reactions, in order to take timely measures. Children, the elderly, pregnant women and those with cardiac, hepatic and renal insufficiencies are often included in the “caution” range, so these groups of people should pay particular attention to observation when using the drug, and once the problem is found, the drug must be discontinued immediately. “Avoid” means to avoid using it as much as possible. Some drugs have greater side effects and may bring adverse consequences to the patient, such as the familiar streptomycin, in the past antibiotics lack of years, because this drug has a certain toxic effect on the nervous system, resulting in some children deaf, now the antibiotic products are very rich, in addition to anti-tuberculosis can sometimes be used clinically, the general anti-infection usage, has been basically eliminated, but other drugs of the same kind, suffering from Tinnitus disease and renal dysfunction should be contraindicated. Drugs that fall within the contraindication range should be avoided if there are no clear indications for their use. “Some drug instructions often include the words “or as directed by a physician” after the words “use and dosage”. One is because the dosage on the instructions is the usual dosage, in view of the patient’s condition, physical condition and sensitivity to drugs, the dosage is different, and the doctor needs to deal with the specific situation; the second is because the nature of drug action is related to the dosage, the dosage is different, the effect is different, such as aspirin is a commonly used antipyretic drug, the antipyretic dose is generally 0.3 to 0.6 grams, three times a day, but if used to prevent But if it is used to prevent ischemic stroke, the dosage must be reduced, generally 100 mg, once before bedtime, so the doctor needs to choose the correct dosage and course of treatment according to the patient’s specific condition, so as to ensure the maximum possible efficacy and reduce side effects. Each drug has a half-life, which is the time it takes for the drug to decay in the blood, and it varies. The half-life of a drug reflects the rate of elimination of the drug in the body, indicating the relationship between the time the drug remains in the body and the blood concentration, which is the main basis for deciding the dose and frequency of administration. For drugs that are eliminated quickly in the body, if the interval between dosing is too long, the blood concentration will be too low to achieve the therapeutic effect; for drugs that are eliminated slowly, if they are used too frequently, they will easily accumulate in the body and cause poisoning. The half-life of a drug is usually referred to as an average, and even for the same drug, the half-life is not exactly the same for different individuals. The half-life of a drug may vary between adults and children, the elderly and pregnant women, and between healthy people and patients. For example, the metabolism of drugs is different in children at different ages, and in patients with hepatic and renal insufficiency, the elimination of drugs is slow and the half-life is relatively longer, so there is a risk of poisoning if drugs are still administered according to the original regulations. Especially for outpatients, if your liver and kidney function is not normal, you must inform the doctor in time. For drugs with a short half-life, if you want to extend the time between dosing, you can make the drug into an extended-release or controlled-release agent, which are commonly known as “long-acting agents”, but there is a difference between the two. “Sustained release” is to make the drug slowly released, absorbed, distributed and excreted in the body through appropriate methods, in order to achieve the purpose of prolonging the action time of the drug in the body. For example, morphine for cancer pain treatment has a half-life of only 4 hours, but when made into morphine extended release tablets, it can be administered every 12 hours, which obviously reduces the number of doses and adverse reactions of patients. The characteristic of “controlled release” is that the drug is released through the controlled release coating, and the drug is released at “equal speed”, “timing” and “quantitative”. “Release” to maintain a constant concentration of the drug in the blood, such as the same as Bison, is a once-a-day dosing. However, special emphasis should be placed on the fact that long-acting drugs must not be broken open and taken.