Osteoarthritis (OA) is a very common age-related degenerative disease that results from the repeated accumulation of chronic injuries over the course of life that are difficult for the body to repair, leading to aging degeneration of all components of the entire synovial joint. The incidence of OA increases with age, with a higher incidence and longer duration of the disease, and the corresponding symptoms become more severe with age. Pain, stiffness and dysfunction of the affected joints are the main symptoms. There is no cure for osteoarthritis, but rather a symptomatic treatment strategy to control the patient’s symptoms, reduce pain and stiffness through a combination of non-pharmacological and pharmacological treatments, restore the function of the joint to the maximum extent possible, and improve the patient’s quality of life. For patients who do not respond well to conservative treatment, surgical treatment can be used to perform artificial knee arthroplasty. Among the pharmacological measures, the only drugs that are really useful are painkillers and glycosaminoglycans, the latter being glucosamine and sodium hyaluronate, with which many patients are familiar. In the hearts of our people, painkillers do not have a very good reputation, as they feel that they only stop the pain but do not really cure the disease, and they also have many side effects, so many patients prefer to endure the pain rather than take painkillers. This kind of thinking is actually indiscriminate and kills a nest of chickens with a stick. First of all, there is no doubt that pain is one of the primary ways in which most diseases afflict patients, and therefore pain relief is one of our main goals in dealing with them, and pain medication is an extremely important weapon in the hands of doctors. Therefore, the problem is not so much about the painkillers themselves, but how we use them wisely. When the cause of the disease is unknown, the casual use of painkillers may mask the symptoms and delay the diagnosis, whereas when the diagnosis is clear, this problem does not exist. Specifically in the treatment of osteoarthritis, when the diagnosis is clear, if mild to moderate pain is present, then the use of pain medication is indeed necessary. Secondly, pain medication is a generic term, but there are in fact many different types of pain medications that have different indications for use in different patient situations. Acetaminophen is recommended as the drug of choice for OA pain management in all 16 of the more influential international OA guidelines. Acetaminophen is a very well-established drug that was first synthesized in 1873, but was not marketed in the United States until 1955 under the trade name Tylenol, and in 1956, a 500 mg tablet of acetaminophen was marketed in the United Kingdom under the trade name Panadol, and in 1963, the drug was added to the British Pharmacopoeia and became popular for its low side effects. It is now used as an over-the-counter drug in Europe and the United States, and can be purchased by patients at most pharmacies and supermarkets without a doctor’s prescription, but this has led to considerable drug abuse. Acetaminophen belongs to the acetanilide class of antipyretic and analgesic drugs, through the thermoregulatory center of the brain to achieve the effect of antipyretic, its antipyretic effect is similar to that of aspirin; and outside the central nervous system by inhibiting the synthesis and release of prostaglandin PGE1, bradykinin and histamine, etc., to improve the pain threshold and play an analgesic effect, belongs to the peripheral analgesic drugs. The analgesic effect of acetaminophen is weak, only effective for mild to moderate pain, and has no significant anti-inflammatory effect. The safety and efficacy of acetaminophen have been confirmed by numerous studies in terms of its analgesic effects. It has a wide range of dose safety, with the highest dose in Europe and the United States typically reaching 4 grams per day, and can be used long-term as needed if the initial use is effective. However, a large Canadian etiology study in 2008, involving 640,000 patients, concluded that long-term use of acetaminophen at doses greater than 3 g/day increased the risk of GI bleeding, perforation, and obstruction, and therefore recommended that long-term use should preferably not exceed 3 g/day. Taking into account the actual situation in China and the principle of on-demand pain relief, we usually recommend avoiding the highest doses in clinical use and generally using it for short- to medium-term rather than long-term use to maximize pain relief while increasing safety and reducing or avoiding side effects. The dose of acetaminophen tablets is usually 650 mg per tablet, and patients are generally advised to take a total of about 3-4 tablets daily, or if the full dose is necessary for effective pain control, it is recommended that the dose be reduced after 2-3 weeks of better pain control. Another advantage of acetaminophen is that it is inexpensive. Acetaminophen has both analgesic and antipyretic properties, leading to its frequent inclusion in many compounded pain medications, but also in many medications used to treat cold and flu symptoms. Therefore, if you need to take cold medications at the same time, you should pay attention to read the drug instructions carefully to find out whether the formula contains acetaminophen, which may appear in cold medications under some other names, such as p-hydroxyphenylacetamide, paracetamol, acetaminophen, p-hydroxyacetanilide, acetaminophen, etc., which are actually acetaminophen, and patients should consult a pharmacist if they are not sure. Patients should consult a pharmacist when they are confused to prevent overdose. Although safe for normal humans at recommended doses, overdose in patients with impaired liver function or chronic heavy alcohol consumption carries a risk of permanent liver failure. Another shortcoming of acetaminophen is that it has weak pain-relieving effects and does not help much with joint stiffness and dysfunction. Guidelines published by the Osteoarthritis Research Society International (OARSI) in 2008 showed that only 15% of patients with OA in the UK were using acetaminophen, another 32% were taking nonsteroidal anti-inflammatory analgesics (NASIDs), 18% were taking cyclooxygenase 2, and the other 20% were taking acetaminophen. A further 32% of patients were taking non-steroidal anti-inflammatory analgesics (NASIDs) and 18% were taking selective inhibitors of cyclooxygenase 2 (COX-2). These drugs are also indicated for mild to moderate pain, but they have a slightly stronger pain-relieving effect than acetaminophen. The problem, however, is that while NASIDs are slightly more effective in relieving pain, they have many times greater gastrointestinal side effects, with the incidence of GI bleeding, perforation, and obstruction about 3-5 times higher than in the placebo group, and most physicians have concerns about their cardiovascular risk. Therefore, the OARSI guidelines recommend that NASIDs should be used at the lowest effective dose and that long-term use should be avoided; for patients at high risk of gastrointestinal complications, NASIDs should be supplemented with a proton pump inhibitor or misoprostol to protect the gastrointestinal tract, or a COX-2 inhibitor. Reading this, many readers must want to be obvious about what exactly these drugs are. In fact, the use of NASIDs drugs is very common, aspirin, anti-inflammatory pain, fentanyl, fotarine, diphenhydramine, lexon, mobicort and so on are this class of drugs. Proton pump inhibitors include omeprazole, lansoprazole, pantoprazole, rabeprazole, and so on. Because NASIDs have a serious risk of gastrointestinal complications, scientists have been searching for drugs that provide pain relief without these side effects. in the 1970s, it was discovered that the pharmacological action of NASIDs requires the inhibition of cyclooxygenase (COX), which has two isomers, called COX-1 and COX-2. 1 produces those side effects when it is inhibited, and COX-2 provides pain relief when it is inhibited. Later on, after more than 20 years of efforts, selective inhibitors of COX-2 were developed, namely Wanluo, Xilabao and Ankangxin, and the two scientists who first discovered COX-2 were awarded the Nobel Prize in Medicine. The two scientists who first discovered COX-2 were awarded the Nobel Prize in Medicine for their work. To date, it has not been lifted. Merzadone has been trying to make a comeback with the launch of a new drug, Enkephalin, in recent years, based on the failure of Wanluo. All these drugs have their own advantages and disadvantages, and the professional background knowledge involved is rather deep and complicated, so it is usually difficult for ordinary patients to clarify them, so they should listen to the guidance of professional doctors and choose a reasonable pain relief plan that suits their own situation. When it is difficult to get good pain relief from these drugs, more advanced narcotic pain medications, such as opioids, are needed, but these drugs also have their own disadvantages and side effects, and doctors usually recommend artificial joint replacement surgery for patients at this stage.