Do different ways of administering medication such as intramuscular, oral or skin patches result in different effects? In order to provide emergency pain relief to patients after surgery or in emergency, pain medications are usually injected intramuscularly, leading to the impression that intramuscular pain medications have the fastest and best effect. However, cancer pain is a long-term, chronic and continuous development process, so pain relief should not only pursue the fast effect, but also the lasting analgesic effect is more important. For cancer pain, the main goal of medication is to maintain the effective concentration of medication in the blood, which is called effective blood concentration in medicine, i.e., if the body is able to maintain the effective blood concentration for 24 hours after taking painkillers, the patient will not have any pain. Myocardial injection used in the injection class painkillers are characterized by fast onset of action, very quickly in the body to reach the peak blood concentration, and may even be more than the effective blood concentration required for treatment, but such drugs are easily metabolized by the body, once lower than the effective blood concentration, the patient will quickly reappear with pain; pain again, due to the original large dose of pain medication on the body’s physiological impact, it is often easy to produce Drug tolerance, the regular dose of drugs will not be enough to achieve the original pain effect, and ultimately make the amount of medication is more and more large, at the same time, the drug side effects will be more and more large. The root cause of drug tolerance is that the rapid onset of action of the injection makes the body also quickly produce antagonistic mechanisms against pain medication. In layman’s terms, for example, the human body has a set of automatic blood glucose level regulation mechanism, when not eating, the human body will secrete the relevant hormones to maintain the stability of blood glucose to meet the needs of various human activities; after eating, the blood glucose will increase rapidly, the higher blood glucose level will stimulate the human body’s blood glucose homeostasis mechanism, secretion of the relevant hormones (insulin) in order to reduce the level of blood glucose. From this point of view, pain relief is the same, with the injection will quickly stimulate the body’s mechanism to fight against analgesic drugs, painkillers to produce tolerance, and ultimately make the effect of pain relief is getting worse and worse. The use of extended-release preparations, such as oral medications and skin patches, [First] blood concentration fluctuations are very small, can maintain the effective blood concentration in the body for a long time; [Second] blood concentration fluctuations will reduce or delay the emergence of the body’s resistance mechanism; [Third] the longer the medication is maintained, the need to increase the frequency of medication will be less frequent, and the side effects are also less. In short, patients should try to choose extended-release formulations during the medication process in order to achieve better results, longer maintenance time, fewer side effects, and less likely to develop drug resistance. How should I choose an extended-release formulation? Cancer pain itself is a progressive process, so the use of painkillers must take into account the long-term effects of the medication, so it is recommended to use extended-release preparations rather than injections or immediate-release oral medications (a type of painkillers with a very rapid onset of action). However, all aspects of the patient’s condition need to be taken into account in the specific process of using extended-release preparations. Extended-release preparations include oral tablets and skin patches, all of which can provide effective analgesia, but are absorbed differently depending on the patient’s physical condition. Generally, most of the initial medication is taken orally because it is convenient. If the intestinal function is not good patients, then choose the patch will be more favorable to absorption, more effective pain relief, because oral intestinal absorption of drugs is limited.