| Drug | Class | Mechanism | ICU Use | Key Adverse Effects |
| Propofol | Induction agent/sedative | GABA-A agonist; rapid onset and offset | First-line IV sedation in ICU; excellent for daily holds | Propofol infusion syndrome (PRIS) at >4 mg/kg/hr >48h; hypotension; hypertriglyceridaemia |
| Midazolam | Benzodiazepine | GABA-A agonist; longer half-life than propofol | Second-line sedation; useful in status epilepticus | Prolonged sedation; accumulates in renal/hepatic failure; increases delirium risk |
| Morphine | Opioid | Mu-receptor agonist | Analgesia; reduce dose in renal failure (active metabolite accumulates) | Constipation; histamine release; pruritus; nausea |
| Fentanyl | Opioid | Mu-receptor agonist; short-acting | Procedural analgesia; infusion for ventilated patients; preferred in renal failure | Chest wall rigidity at high doses; less histamine release than morphine |
| Ketamine | Dissociative anaesthetic | NMDA antagonist | Procedural sedation; analgesia; bronchodilator; preserves airway reflexes and haemodynamics | Emergence phenomena; raises ICP (caution in neurosurgical patients — though this is debated); increases secretions |
| Haloperidol | Typical antipsychotic | Dopamine D2 antagonist | Delirium management (limited evidence); agitation | QTc prolongation; extrapyramidal effects; avoid in Parkinson’s |
| Dexmedetomidine | Alpha-2 agonist | Sedation without respiratory depression | Sedation in weaning from ventilation; reduces delirium | Bradycardia; hypotension |