1. Drug-Induced Liver Injury (DILI) Professor Kassim Al-Saudi M.B.,Ch.B.,Ph.D

3. Importance Prognosis may be worse than for viral hepatitis Responsible for 3% to 10% of all adverse drug reactions; frequency appears to be increasing Drugs and toxins responsible for 1/3 of cases of fulminant hepatic failure Drug injury can mimic all forms of liver disease

4. B O O E Z D R U G C O K E Burger B L O O D Obesity/ diabetes Abnormal liver tests HCV HBV FOURTH CAUSE 9%* * Bagheri, Br J Clin Pharmac 2000;50:479.

5. Risk Factors

6. Chronic Ethanol Use Increases Sensitivity of Liver to Hepatotoxins Anesthetic agents Acetaminophen Isoniazide Cocaine Vitamin A Aflatoxins Methotrexate Carbon Tetrachloride

7. Young adults DILI and age High drug consumption Old Children Exceptions: Reye’s syndrome with aspirin and Reye-like syndrome with valproate > >  Susceptibility (e.g., isoniazid)

8. (Same in females and males before 50) DILI and gender Incidence of DILI: 2.6-fold higher in females than males in persons aged 50 years or more

9. CIRRHOSIS - Does not change the incidence of DILI - but worsens it outcome (The same degree of liver injury, which is well tolerated in a normal subject, can trigger liver failure, complications and death in patients with an already impaired liver function) DILI in cirrhosis

11. DIAGNOSIS DILI is most often a diagnosis of exclusion. All the known causes of liver disease have to be excluded. Common diseases to be excluded are viral hepatitis, autoimmune disorders, Alcohol intake, Metabolic and genetic disorders, hemodynamic dysfunction and billiary abnormalities. Perform relevant investigations.

14. Clinicopathologic Classification of Drug-Induced Liver Disease

17. General Mechanism

18. Acetaminophen Liver Toxicity

19. Acetaminophen is hepatotoxic in large doses and often used to commit suicide Acetaminophen metabolism creates toxic metabolites that cause zone 3 necrosis when present at levels exceeding the liver’s detoxification capacity Acetaminophen Hepatotoxicity

20. Evolution of injury in three phases – Phase I –acute GI symptoms (1-4 hours) – Phase II –latent (1-3 days) – Phase III –liver damage/failure (3-10 days) About 15% of patients with overt liver injury die Acetaminophen Hepatotoxicity

21. FULMINANT HEPATITIS IN THE USA OTHER CAUSES: 48% OTHER DRUGS: 12% PARACETAMOL: 40% DRUGS: 52% Intentional overdoses Self medication with excessive doses in the USA

22. In overdose situations, liver enzymes become saturated, glutathione is depleted, NAPQI (N-acetyl-p-benzoquinoneimine) accumulates, and hepatic necrosis occurs

23. Toxic dose –In adults, threshold for liver damage is 150 to 250 mg/kg –Children under 10 appear to be more resistant

24. Potential liver damage –Adults: > 150 mg/kg in acute dose –Adults: > 7.5 Grams in 24 hours (chronic) –Children ( 200 mg/kg

25. Glutathione: Role in Acetaminophen- Induced Liver Disease

26. Treatment of Acetaminophen Toxicity

27. GI decontamination –Syrup of Ipecac return usually 30-40% at best best if used early (first 1-2 hours) –Gastric lavage effectiveness diminishes with time Treatment of Acetaminophen Toxicity

28. Activated charcoal –Should not be witheld –dose 50-100 Grams Cathartic –utilized to speed transit time

29. Hemodialysis –Limited benefit –Damage occurs quickly Hemoperfusion –No benefit Peritoneal dialysis –No benefit

30. 4 hour post ingestion APAP level –levels drawn earlier may be erroneous –levels may be accurate up to 18 hours

31. N-acetylcysteine (NAC) Mechanism of action –glutathione substitute –may supply inorganic sulfur, altering metabolism Route of administration –Orally or IV IV not approved in the U.S.

32. NAC dosing –Oral 72 hour protocol Loading dose is 140 mg/kg Maintenance doses: 70 mg/kg –Given every 4 hours x 17 doses starting 4 hours after loading dose

33. NAC supplied as 10 or 20% oral solution –dilute to 5% final concentration with juice or soft drink –May be administered via NG tube –If emesis occurs within 1 hour of administration, repeat the dose

34. If emesis persists, antiemetics may be used –Reglan® (metoclopramide) 0.1 to 1.0 mg/kg iv is often effective –If emesis is refractory, may consider Zofran® (ondansetron) or Kytril® (granisetron) Expensive, but very effective

35. NAC side effects Relatively free of side effects when given orally Emesis may occur –extremely offensive sulfur odor

36. Points to remember APAP is present in many poly drug overdoses No symptoms may be present…screen 150 mcg/ml at 4 hours is a “treat” level NAC loading dose is 140 mg/kg NAC maintenance doses are 70 mg/kg Once NAC is started, DO NOT DC Metoclopramide 0.1-1.0 mg/kg is very effective in controlling nausea/vomiting associated with APAP toxicity

37. CONCLUSION TWO GOLDEN RULES 1. Always consider the possibility of DILI 2. Immediately withdraw all suspected drugs in severe cases DILI: Difficult to avoid, predict and diagnose

40. The End And Happy Eid