Introduction

• NSAIDs are commonly used for perioperative pain management.
• In cirrhotic patients, their use must be reconsidered due to:
• Altered pharmacokinetics and pharmacodynamics
• Fragile homeostasis
• Risk of renal, gastrointestinal, and bleeding complications
• Understanding these mechanisms at the molecular level improves safe anesthesia care.

Pathophysiology

Renal Hypoperfusion and Prostaglandin Dependency

• Cirrhosis → systemic and splanchnic vasodilation (mediated by nitric oxide and endotoxemia).
• Result → reduced effective arterial blood volume.
• Kidneys depend on prostaglandin-mediated afferent vasodilation (PGE2, PGI2 via EP2/EP4 and IP receptors).
• NSAIDs → inhibit COX-1 and COX-2 → suppress prostaglandin synthesis.
• Consequence → loss of renal protective vasodilation → functional AKI or hepatorenal syndrome.

• Ascites
• Rising creatinine
• Mean arterial pressure <65 mmHg

• Bernardi M, et al. J Hepatol. 2015;63(6):1272–82.
• García-Martínez R, et al. Int J Mol Sci. 2020;21(24):9452.
• Bataller R, Ginès P. N Engl J Med. 2005;353(14):1543–51.

Platelet Dysfunction and Hemostasis Instability

• Cirrhosis causes a rebalanced but fragile hemostatic system.
• Mechanisms include:
• Reduced synthesis of clotting factors
• Thrombocytopenia (splenic sequestration)
• Endothelial dysfunction
• Platelets depend on COX-1–derived TXA2 → activates TP receptors → calcium influx → aggregation.
• NSAIDs block TXA2 synthesis → impair platelet function → increase bleeding risk.

• Avoid NSAIDs in patients undergoing neuraxial procedures.
• Avoid in patients with varices or mucosal bleeding risk.

• Tripodi A, Mannucci PM. N Engl J Med. 2011;365(2):147–56.
• Blasi A, et al. J Hepatol. 2018;69(6):1245–56.
• Patrono C, et al. Circulation. 2001;103(10):1179–84.

GI Mucosal Injury

• Cirrhosis → portal hypertension → gastropathy, vascular congestion, impaired mucosal defenses.
• Prostaglandins (PGE2 via EP receptors) maintain mucosal blood flow and mucus production.
• NSAIDs block prostaglandins → decreased bicarbonate/mucus secretion, mucosal ischemia.
• Enterohepatic recirculation prolongs exposure and injury.

• Perioperative stress, fasting, and mechanical ventilation worsen NSAID-related GI risks.

• Lanas A, et al. Gastroenterol Clin North Am. 2009;38(2):277–95.
• Sostres C, et al. Curr Med Chem. 2010;17(28):2892–7.
• Laine L. Gastroenterology. 2001;120(3):594–606.

Pharmacokinetics

Altered Plasma Protein Binding

• NSAIDs are highly albumin-bound (>95%).
• Cirrhosis → hypoalbuminemia + competition from bilirubin.
• Results:
• Increased free drug fraction
• Enhanced toxicity at standard doses
• Potential bilirubin displacement worsening hepatic encephalopathy

• Avoid highly bound NSAIDs in hypoalbuminemic patients.
• If used, reduce dosage.

• Verbeeck RK. Eur J Clin Pharmacol. 2008;64(12):1147–61.
• Morgan DJ, et al. Clin Pharmacokinet. 1983;8(2):107–25.
• Pacifici GM. Clin Pharmacokinet. 1988;14(4):271–81.

Impaired Hepatic Metabolism

• Cirrhosis reduces Phase I metabolism (CYP450s, especially CYP2C9 and CYP3A4).
• Phase II conjugation is relatively preserved.
• Consequences:
• Prolonged half-life
• Drug accumulation
• Increased risk of adverse effects (notably with diclofenac, piroxicam).

• Avoid regular or repeated NSAID dosing.
• Monitor for cumulative effects.

• Reuben A. Zakim and Boyer’s Hepatology. 2012.
• Verbeeck RK. Br J Clin Pharmacol. 1991;32(5):529–34.
• Lee WM. N Engl J Med. 2003;349(5):474–85.

Clinical Integration

Key NSAID Risks in Cirrhosis

• Renal failure (AKI, HRS): due to loss of prostaglandin-mediated afferent vasodilation.
• Bleeding: due to impaired platelet aggregation.
• GI ulcer/bleed: due to reduced mucosal protection.
• Drug toxicity: due to low albumin and impaired CYP metabolism.

• Pain plans should integrate hepatic function and NSAID molecular pharmacology.

• Grosser T, et al. Goodman & Gilman’s Pharmacological Basis of Therapeutics. 13th ed. 2018.
• Runyon BA. Hepatology. 2013;57(4):1651–3.
• Kim WR, et al. Hepatology. 2009;49(6):2087–107.

Safer Alternatives to NSAIDs

Paracetamol

• Mechanism: central COX inhibition
• Metabolism: conjugation (safe if ≤2 g/day)
• Considered safe with monitoring.

Gabapentin

• Mechanism: binds α2δ calcium channel subunit
• Metabolism: renal excretion
• Safe in cirrhosis; adjust dose in renal impairment.

Ketamine

• Mechanism: NMDA receptor antagonist
• Metabolism: hepatic, low extraction ratio
• Useful as opioid-sparing analgesic.

Dexmedetomidine

• Mechanism: α2 agonist reducing norepinephrine release
• Metabolism: hepatic
• Safe at low doses.

Clonidine

• Mechanism: central α2 agonist
• Metabolism: hepatic and renal
• Use cautiously; risk of bradycardia.

• Tzschentke TM, et al. CNS Drugs. 2007;21(12):847–73.
• Ebert TJ, et al. Anesthesiology. 2000;93(4):1138–44.
• McCartney CJL, et al. Anesth Analg. 2004;99(2):408–20.

Conclusion

• NSAIDs are unsafe in cirrhotic patients due to risks of renal failure, bleeding, GI injury, and drug accumulation.
• Even short courses may provoke life-threatening complications.
• Safer analgesic alternatives (paracetamol, gabapentin, ketamine, α2 agonists) should be prioritized and tailored to liver function.