(1) Constipation Almost all patients using opioid analgesics have constipation. Constipation is often more difficult to manage clinically than pain control; therefore, when starting opioid analgesics, a regular laxative regimen should be initiated, including laxatives and stool relaxants: e.g., senna, methylcellulose, phenol peptides, paraffin oil, etc.; attention should also be paid to adjusting the patient’s diet. (2) Respiratory depression is potentially the most serious side effect of opioid use. It usually occurs in patients who use opioids for the first time and at too high a dose, and is caused by central nervous system depression along with pain relief, and the risk of this complication decreases with repeated use. When respiratory depression occurs, apply 1:10 naloxone diluted solution for slow intravenous drip treatment; tracheotomy should be done for comatose patients. (3) Sedation and drowsiness can occur after the first or repeated use of opioid analgesics. Although patient sedation is sometimes clinically indicated, they are not a required component of analgesics, especially in ambulatory patients. Management includes reducing the dose of individual drugs or lengthening the interval between doses, and also using drugs with a shorter plasma half-life. (4) Nausea and vomiting 2/3 of patients using opioid analgesics have varying degrees of nausea and vomiting, which can be treated with mepiquat chloride, methotrexate, vitamin B6 and other drugs. (5) Acute intoxication manifested as respiratory depression, coma, constricted pupils and digestive tract spasm, etc. Opioid antagonist naloxone is chosen to treat adoptive, and naloxone can competitively block and replace the binding of opioids to receptors and block their effects to eliminate the symptoms of intoxication. (6) Physical dependence and drug resistance The use of opioid analgesics can be accompanied by the emergence of physical dependence and drug resistance, which is a normal pharmacological response to the use of such drugs. Physical dependence is characterized by withdrawal syndrome when treatment is suddenly stopped. Drug resistance is characterized by a decrease in efficacy with repeated use of the drug and the need to increase the dose or shorten the interval between doses to maintain pain relief. Physical dependence and resistance do not prevent opiate pain medications from working, and research data indicate that: most patients require a gradual increase in dose from first use until death; 1/3 of patients can maintain a stable dose throughout the course of treatment; about 20% of patients require a reduction in dose during the course of treatment. Many clinical experiences have shown that when morphine is given regularly to those patients for whom opioids are effective, there is no resistance problem; when an increase in dose or change in drug type is required, it is not necessarily due to the development of resistance, but often due to an increase in pain caused by disease progression; however, abuse of opioid analgesics can increase the risk of resistance; doses that are “too small “However, the abuse of opioid analgesics can increase the risk of drug resistance; too small a dose or “as needed” administration often makes the pain persist or reappear, which means that the purpose of pain relief is not achieved and drug resistance is more likely to occur. (7) Psychiatric dependence Psychiatric dependence, known as addiction, is a form of behavior that accompanies drug abuse. It is characterized by a craving for medication and an unstoppable effort to obtain it for “comfort” rather than for pain relief. Numerous clinical experiences have shown that psychiatric dependence rarely occurs in patients who use opioid analgesics for chronic cancer pain, for example, one study pointed out that out of 12,000 patients who used opioids for cancer pain, only 4 cases became addicted.