Analgesica

Analgesica, or analgesics, are drugs that relieve pain without producing significant loss of consciousness. They are used to treat mild to severe pain and may be administered alone or as part of a multimodal strategy. Analgesics are categorized by mechanism and strength into non-opioid analgesics, opioid analgesics, and adjuvant analgesics.

Non-opioid analgesics include most nonsteroidal anti-inflammatory drugs and acetaminophen. They reduce pain by peripheral mechanisms such as inhibition of cyclooxygenase and prostaglandin synthesis, and can also have anti-inflammatory effects. Opioid analgesics, which act on central mu receptors, provide potent analgesia for moderate to severe pain but carry risks such as respiratory depression, sedation, dependence, and constipation. Adjuvant analgesics, including certain antidepressants, anticonvulsants, corticosteroids, and local anesthetics, are used to enhance analgesia or treat neuropathic pain.

Indications include acute injuries, postoperative pain, chronic conditions such as osteoarthritis, neuropathic pain, and cancer-related pain. Dosing and choice depend on severity, patient factors, and risk of adverse effects. Common safety considerations include gastrointestinal bleeding and kidney injury with NSAIDs, liver toxicity with high-dose acetaminophen, and misuse or dependence with opioids. Drug interactions, especially with anticoagulants, alcohol, or CNS depressants, are important to monitor.

Analgesics are widely available: many non-opioids are over-the-counter; most strong opioids require prescription. Historical milestones include aspirin in the late 19th century and the development of synthetic analgesics in the 20th century. See also analgesic ladder and multimodal analgesia.