Module 34 · ICU care & pharmacology

Analgesia, sedation and delirium

NewPhase 2

Analgesia, sedation and delirium in the ICU (PADIS 2018 and 2025 update, eCASH): pain assessment and analgosedation, RASS-guided light sedation and agent choice, CAM-ICU delirium care, neuromuscular blockade, and alcohol withdrawal.

5 topics

Drugs in this module

Doses written for this module's context. The same drug may read differently in another module.

Fentanyl

Opioid analgesic

Indications
First-line ICU analgesia (analgosedation)
Adult dose
Bolus 25-100 mcg IV; infusion 25-200 mcg/h (about 0.5-3 mcg/kg/h), titrated to CPOT/BPS.
Preparation (India)
50 mcg/mL; e.g. 500 mcg in 50 mL = 10 mcg/mL.
Cautions
Accumulates with prolonged infusion (context-sensitive half-life), chest wall rigidity with large boluses, constipation.

Paracetamol

Non-opioid analgesic

Indications
Multimodal analgesia (opioid-sparing)
Adult dose
1 g IV/oral every 6 h (max 4 g/day; 2-3 g/day if weight < 50 kg, malnutrition, chronic alcohol use or liver disease).

Ketamine

NMDA antagonist

Indications
Adjunct analgesia (opioid-sparing), sedation in bronchospasm/haemodynamic instability
Adult dose
Analgesia: 0.1-0.5 mg/kg IV bolus, then 0.05-0.4 mg/kg/h. Sedation: 0.5-2 mg/kg/h.
Preparation (India)
50 mg/mL; 500 mg in 50 mL = 10 mg/mL.
Cautions
Hypersalivation, emergence phenomena, raised BP/HR.

Morphine

Opioid analgesic

Indications
Analgesia (alternative to fentanyl)
Adult dose
Bolus 2-4 mg IV; infusion 2-10 mg/h.
Renal / hepatic
Active metabolite (M6G) accumulates in AKI - prefer fentanyl.
Cautions
Histamine release, hypotension.

Propofol

GABA-A agonist sedative

Indications
Light-to-deep sedation in ventilated patients
Adult dose
0.3-3 mg/kg/h (5-50 mcg/kg/min) infusion; avoid > 4 mg/kg/h for > 48 h.
Preparation (India)
1% = 10 mg/mL.
Cautions
Hypotension, hypertriglyceridaemia (lipid 1.1 kcal/mL), propofol infusion syndrome (acidosis, rhabdomyolysis, arrhythmia).
Monitoring
Triglycerides every 48-72 h; CK/lactate if high dose.

Dexmedetomidine

Alpha-2 agonist

Indications
Light sedation; delirium/agitation; facilitating extubation
Adult dose
0.2-1.4 mcg/kg/h infusion (loading dose usually omitted in ICU because of bradycardia/hypotension).
Preparation (India)
100 mcg/mL; 200 mcg in 50 mL NS = 4 mcg/mL.
Cautions
Bradycardia, hypotension; does not provide deep sedation alone; SPICE III signal of harm in older patients (> 65) when used as early sole sedative.

Midazolam

Benzodiazepine

Indications
Deep sedation when propofol unsuitable; status epilepticus; alcohol withdrawal adjunct
Adult dose
Bolus 1-2 mg (0.01-0.05 mg/kg) IV; infusion 0.02-0.1 mg/kg/h.
Renal / hepatic
Active metabolite accumulates in AKI.
Cautions
Associated with delirium and prolonged ventilation; avoid as routine sedative.

Haloperidol

Typical antipsychotic

Indications
Distressing hyperactive delirium/agitation endangering safety (not routine)
Adult dose
2.5-5 mg IV every 6-8 h as needed (max ~20 mg/day; lower in elderly).
Cautions
QTc prolongation (check ECG, avoid if QTc > 500 ms), extrapyramidal effects, NMS.

Quetiapine

Atypical antipsychotic

Indications
Persistent agitated delirium (adjunct)
Adult dose
25-50 mg orally/NG every 12 h, titrate to 200 mg twice daily.
Cautions
Sedation, hypotension, QTc.

Melatonin

Chronobiotic

Indications
Sleep promotion in ICU
Adult dose
3-10 mg orally/NG at night (doses in trials vary).

Cisatracurium (or atracurium)

Non-depolarising NMB (Hofmann elimination)

Indications
Severe ARDS, refractory raised ICP, shivering during TTM, ventilator dyssynchrony
Adult dose
0.15-0.2 mg/kg bolus, then 1-3 mcg/kg/min (ACURASYS fixed 37.5 mg/h); atracurium 0.5 mg/kg then 0.3-0.6 mg/kg/h.
Preparation (India)
2 mg/mL; 100 mg in 50 mL = 2 mg/mL.
Cautions
Must ensure deep sedation and analgesia first; ICU-acquired weakness; eye care.
Monitoring
Train-of-four 1-2/4 plus clinical assessment.

Rocuronium

Non-depolarising NMB (aminosteroid)

Indications
NMB infusion where benzylisoquinoliniums unavailable
Adult dose
0.6-1.2 mg/kg bolus; infusion 0.3-0.6 mg/kg/h.
Renal / hepatic
Prolonged in hepatic/renal failure.
Cautions
Reversible with sugammadex.

Diazepam

Long-acting benzodiazepine

Indications
Alcohol withdrawal
Adult dose
10-20 mg IV/oral every 1-2 h (symptom-triggered or front-loading) until CIWA-Ar < 10 or light sedation; IV boluses 5-10 mg every 5-10 min for severe withdrawal/DTs.
Preparation (India)
5 mg/mL ampoules.
Cautions
Accumulation in liver disease and elderly (use lorazepam); respiratory depression.

Lorazepam

Intermediate-acting benzodiazepine

Indications
Alcohol withdrawal in liver failure or elderly
Adult dose
1-4 mg IV every 5-15 min for severe withdrawal, or 2-4 mg oral every 1-2 h symptom-triggered.

Phenobarbital

Barbiturate

Indications
Benzodiazepine-resistant alcohol withdrawal (or monotherapy protocols in ICU)
Adult dose
10 mg/kg IV over 30 min (single loading dose, ideal body weight), or 130-260 mg IV every 15-30 min titrated.
Cautions
Respiratory depression with benzodiazepines; long half-life.

Thiamine

Vitamin B1

Indications
Prevention/treatment of Wernicke encephalopathy in alcohol use or malnutrition
Adult dose
Prevention 100-200 mg IV daily; suspected Wernicke 200-500 mg IV three times daily for 3-5 days; give before glucose.

Module references (14)

  1. 1

    Devlin JW, Skrobik Y, Gelinas C, et al. Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU (PADIS). Crit Care Med 2018;46:e825-73.

  2. 2

    Lewis K, Balas MC, Stollings JL, et al. A focused update to the clinical practice guidelines for the prevention and management of pain, anxiety, agitation/sedation, delirium, immobility, and sleep disruption in adult patients in the ICU. Crit Care Med 2025;53:e711-27.

  3. 3

    Vincent JL, Shehabi Y, Walsh TS, et al. Comfort and patient-centred care without excessive sedation: the eCASH concept. Intensive Care Med 2016;42:962-71.

  4. 4

    Gelinas C, Fillion L, Puntillo KA, Viens C, Fortier M. Validation of the Critical-Care Pain Observation Tool in adult patients. Am J Crit Care 2006;15:420-7.

  5. 5

    Sessler CN, Gosnell MS, Grap MJ, et al. The Richmond Agitation-Sedation Scale: validity and reliability in adult intensive care unit patients. Am J Respir Crit Care Med 2002;166:1338-44.

  6. 6

    Girard TD, Kress JP, Fuchs BD, et al. Efficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (ABC trial). Lancet 2008;371:126-34.

  7. 7

    Shehabi Y, Howe BD, Bellomo R, et al. Early sedation with dexmedetomidine in critically ill patients (SPICE III). N Engl J Med 2019;380:2506-17.

  8. 8

    Hughes CG, Mailloux PT, Devlin JW, et al. Dexmedetomidine or propofol for sedation in mechanically ventilated adults with sepsis (MENDS2). N Engl J Med 2021;384:1424-36.

  9. 9

    Ely EW, Inouye SK, Bernard GR, et al. Delirium in mechanically ventilated patients: validity and reliability of the Confusion Assessment Method for the ICU (CAM-ICU). JAMA 2001;286:2703-10.

  10. 10

    Girard TD, Exline MC, Carson SS, et al. Haloperidol and ziprasidone for treatment of delirium in critical illness (MIND-USA). N Engl J Med 2018;379:2506-16.

  11. 11

    Andersen-Ranberg NC, Poulsen LM, Perner A, et al. Haloperidol for the treatment of delirium in ICU patients (AID-ICU). N Engl J Med 2022;387:2425-35.

  12. 12

    Murray MJ, DeBlock H, Erstad B, et al. Clinical practice guidelines for sustained neuromuscular blockade in the adult critically ill patient. Crit Care Med 2016;44:2079-103.

  13. 13

    National Heart, Lung, and Blood Institute PETAL Clinical Trials Network. Early neuromuscular blockade in the acute respiratory distress syndrome (ROSE). N Engl J Med 2019;380:1997-2008.

  14. 14

    The ASAM clinical practice guideline on alcohol withdrawal management. J Addict Med 2020;14(3S Suppl 1):1-72.