We've just mentioned three poisonous herbs. Now I'd like to introduce factors that affect drug safety. Actually, drug safety involves multiple factors. These include people who use the drugs, people who prescribe the drugs and what conditions the drugs are used for. In other words, factors affecting the drug safety () are associated with the materia medica; (2) are associated with doctors who prescribe; (3) are associated with patients. So I'd like to explain from these three aspects. First, let's take a look at the materia medica this is an objective factor, especially for poisonous herbs. The main active components, sometimes the active component and toxic component are the same substance. We need to exert its efficacy but avoid its toxicity. You need to be ver cautious to choose herbs. As for poisonous herbs, we mentioned that some are highly poisonous. To be honest, the chances of using these herbs are slim. As a result, there is no need to worry about their risk, because they are under strict regulation. Undoubtedly, safety issue is highlighted for products under regulation. This is one aspect. For some herbs that are mildly toxic but popular in the market, we need to pay much more attention because inappropriate use may cause toxicity. Of course this may not severely harm the body. This is one aspect. The second aspect, the materia medica itself is not toxic, however it becomes toxic when it's contaminated. The use of contaminated materia medica involves with the administration and dispensary. This is about contaminated materia medica. Now let's give you an example. We know that years, or more than 10 years ago, during the spread of SARS in 2003, all Chinese people took Chinese medicine. This indicates that Chinese medicine is effective for disease prevention and treatment, even for acute contagious diseases, which have been recognized and approved. Another aspect, it also indicates some people just take blindly. At that time, Guan Zhong (Rhizoma Cyrtomii) was in short supply. It's believed that it can defend against SARS and prevent SARS. As a result, this herb was rarely used for an extended period of time, or even forgotten. All of a sudden, it became so effective that people rushed to buy this herb. In Chinese medicine, for Chen Pi (Pericarpium Citri Reticulatae): the older, the better; for Guan Zhong: the fresher, the better. That's to say, older Guan Zhong have poorer effect. Since it has not been used for a long time, all of a sudden, people realized it's good and rushed to buy, including contaminated one in the market. It was reported that some people had their liver and kidney damaged after taking Chinese herbs to prevent SARS, one of the herbs is Guan Zhong. This is the issue regarding the materia medica. Thirdly, it's related to the type of the herb. Previously we mentioned Long Dan Xie Gan Wan (Gentian Liver-Draining Pill), in which an ingredient that can damage the kidney function is Guan Mu Tong (Caulis Aristolochiae Manshuriensis). However, there are many subtypes of Mu Tong (Caulis Akebiae), such as Mu Tong, Chuan Mu Tong (Caulis Clematidis Armandii), and Guan Mu Tong is just one subtype. If you choose randomly before getting to know the types, safty issues may emerge. This is the factor related to the materia medica. The second factor is related to doctors. We think doctors should play a leading role in this issue, because it is the doctor who choose the herbs, decide the dosage educate the patients to use in a correct way. So doctors are key to drug safety. In this regard, we'd like to mention the following aspects. First, the herb needs to match with the syndrome. Whether it's symptom-oriented or pattern-oriented, the prescription needs to be directed at the syndrome. I've mentioned that not many safety issues result from really toxic herbs, most safety issues are related to atoxic or mildly toxic herbs, for example, inconsistency bewteen prescription and syndrome. We've mentioned once about in the case of yang excess, swallowing Gui Zhi (Ramulus Cinnamomi) can be fatal. Since Gui Zhi is very warm and hot in property, it's undoubtedly indicated for cold syndrome. If you use Gui Zhi for warm-heat syndrome instead of cold syndrome, side effects will surely occur. Therefore it may sound easy to say the prescription shall match with the syndrome; it's not so easy in clinical practice. This is the factor related to doctors. Secondly, about the dosage. Even if a herb is toxic, a well-controlled dose can tranform toxicity into treasure and benefit the treatment. So in many cases, whether a herb is toxic or there is a safety risk largely depends on the dosage. As a result, toxicologically, a classical saying goes, medicine itself is not toxic, whereas the dosage is the culprit. Let me tell you a true story. A senior doctor that supervises students prescribes Yang Jin Hua (Flos Daturae) for a patient. We know that Yang Jin Hua has anesthetic effect and can be used to relieve coughing and asthma. Generally the daily dose is no more than 1.5g; however, his student neglected the decimal point, turning 1.5g into 15g. It turned out that the patient lost consciousness after taking the formula. This event does not need to go to court, it's the doctor's fault. Although the doctor himself didn't do it, his student was not entitled to prescribe the supervisor shall be fully responisble for the event. So the dosage is extremely important. Thirdly, instead of one single herb, our prescription contains several herbs. In this case, we need to consider the compatibility, which is closely related to whether the formula is effective, highly effective and safe. I'd like to say a few words about compatibility. The purposes of compatibility: (1) to strengthen the therapeutic efficacy: one herb can be effective but not enough potency, a similar herb can be used in combination, achieving the effect of "1+1>2'. (2) To counteract: one herb is necessary but may cause side effects; and other herbs can be used in combination to prevent the side effects to counteract. Additionally, sometimes it's necessary to reduce or weaken its potency. However, combination of herbs may cause side effects. About compatibility, there is 'compatibility among seven conditions' in Chinese medicine... single herb, mutual reinforcement, mutual assistance, mutual restraint, mutual suppression, mutual inhibition and antagonism. These seven combinations may result in four possible outcomes: (1) strengthen the efficacy, mainly through mutual reinforcement and mutual assistance; (2) counterbalance through mutual restraint and mutual suppression; (3) weaken the efficacy through mutual inhibition; (4) result in or strengthen toxic reactions through antagonism. For treatment, we hop the combination can strengthen the efficacy sometimes by counteracting or mutual inhibition in special occasions. For example, we all know ginseng tonifies qi, and usually we do not eat raddish when we take ginseng. Why? Because raddish disperses qi. Raddish Raddish can neutralize the qi-tonifying action of ginseng. When you used ginseng by mistake or used too much ginseng, you can eat a little raddish or raddish seeds called Lai Fu Zi (Semen Raphani) to neutralize. However, it is absolutely prohibited to use antagonism, which has been stipulated in the national pharmacopoeia. The main contents have been generalized in the form of rhymes by ancient people. Ban Wei Bei Lian Ji Gong Wu, meaning that Ban Xia (Rhizoma Pinelliae), Gua Lou (Fructus Trichosanthis), Bei Mu (Bulbus Fritillaria), Bai Lian (Radix Ampelopsis) and Bai Ji (Rhizoma Bletillae) cannot be used in combination with Wu Tou, including Chuan Wu (Radix Aconiti), Cao Wu (Radix Aconiti Kusnezoffii) and Fu Zi (Radix Aconiti Lateralis), etc. It clearly states that the aforementioned drugs cannot be used together. Also the rhyme goes 'Zao Ji Sui Yuan Ji Zhan Cao', meaning that Hai Zao (Sargassum), Da Ji (Radix Euphorbiae Pekinensis), Gan Sui (Radix Kansui) and Yuan Hua (Flos Genkwa) cannot be used in combination with Gan Cao (Radix et Rhizoma Glycyrrhizae). Also, Zhu Shen Xin Shao Pan Li Lu, 'Shen' here includes Ren Shen (Radix et Rhizoma Ginseng), Dang Shen (Radix Codonopsis), Xi Yang Shen (Radix Panacis Quinquefolii), Tai Zi Shen (Radix Pseudostellariae), Dan Shen (Radix et Rhizoma Salviae Miltiorrhizae), Xuan Shen (Radix Scrophulariae), Sha Shen (Radix Adenophorae seu Glehniae) all these cannot be used in combination with Li Lu (Radix et Rhizoma Veratri Nigri), neither can Xi Xin (Radix et Rhizoma Asari), Chi Shao (Radix Paeoniae Rubra) and Bai Shao (Radix Paeoniae Alba). Our ancestors learned these with a price and we should keep in mind. These contents are listed as combination contraindications in the pharmacopoeia. That's why we say the safety issue is more related to the doctors. Of course there are some special periods, for example, women during period, childbirth and pregnancy cannot use some herbs. In addition, this is also related to the route of administration. So Doctors are the key in this process. Finally, the patient-related factor. It's actually still related to doctors. As doctors, you have to remind, correct and instruct how to use herbs appropriately. When you realize patients have wrong ideas or misunderstandings, you have to correct and educate them. These include the decoction, administration cautionary notes, and dietary habits, etc. Some herbs need to be decocted for a long time but you failed to do so or have no idea; some herbs only need to be decocted for a while, but you decocted for a long time; some herbs need to be wrapped up during decoction, for example, Pi Pa Ye (Folium Eriobotryae) needs to be wrapped up in a gauze bag, otherwise, it floats in the decocted water and may cause vomiting as soon as you swallow. All these information shall be informed by doctors. The patients then follow the doctors' instrucdtions. Some safety issues are inevitable. What? Individual differences. As for doctors' prescription, even if the dose, method and syndrome are all correct, patients' still experienced side effects, which is related to patients' constitutional differences. We need to keep a close look at these issues as well. In this class, I talked about some factors affecting the drug safety, involving the patient, doctor and materia medica, especially the doctor. So much for this session.
