Abstract
Objective: To present information on the mechanism of action, indications and contraindications of the main opioids used in palliative care, supporting the correct and safe prescription. Bibliographic review: Opioids are effective analgesic drugs for moderate or severe pain, despite their effectiveness, there is resistance to their use by both physicians and patients, as it can cause physical dependence, respiratory depression, among other unwanted side effects. Thus, synthesizing about these drugs allows for a critical assessment so that the best therapeutic plan is offered to the patient. Morphine is commonly the most used opioid, fentanyl is the most potent and methadone has the longest action time. The indication of each should be well evaluated according to the therapeutic plan proposed by the multidisciplinary team, because pain control is not achieved only with the use of analgesics, as it has bio-psychosocial and spiritual components that must be worked on. Final considerations: The importance of knowing the mechanism of action of opioids was determined, in order to intervene early in adverse effects and provide greater safety in their administration, thus obtaining a direct effect on the quality of life during palliative care.