This chapter explores analgesic pharmacology, focusing on medications frequently employed in anaesthesia and perioperative care. The chapter commences with a comprehensive examination of non-steroidal anti-inflammatory drugs (NSAIDs), detailing their mechanisms of cyclo-oxygenase inhibition, pharmacological characteristics, clinical indications, and potential adverse effects, particularly gastrointestinal, renal, anSd cardiovascular risks. Aspirin and paracetamol are highlighted individually, emphasizing their distinct pharmacokinetics, safety profiles, and therapeutic considerations, including aspirin’s irreversible platelet inhibition and paracetamol’s hepatotoxicity management. The chapter subsequently provides an extensive overview of opioids, addressing receptor pharmacology, clinical indications, and opioid-specific adverse effects such as respiratory depression, tolerance, dependence, and hyperalgesia. Individual opioids—morphine, fentanyl, remifentanil, tramadol, and codeine—are analyzed thoroughly, focusing on their unique pharmacokinetics, potency comparisons, clinical uses, and side effect profiles. This chapter promotes a structured understanding of multimodal analgesia, enabling trainees to optimize pain management strategies effectively while minimizing associated risks and adverse events.