Level 3 Organ System: Digestive System Disease State: Gastrointestinal / Mental Curriculum Topic: Pharmacy Practice / Pharmacist-Provided Care / Pharmacotherapy Treatment of an Acetaminophen Overdose Mate M. Soric, PharmD Assistant Professor of Pharmacy Practice, Northeastern Ohio Universities College of Pharmacy Social History Key Learning Objectives  Smoker: 1.5 pack per day x 11 years 1. Describe the pathophysiology of acetaminophen overdose,  Denies drinking alcohol including normal acetaminophen metabolism, toxic metabo-  Denies illicit drug use lite production, and the mechanism of cellular damage. Family History 2. Identify patient risk factors for the development of liver in- jury or failure following an acute acetaminophen overdose.  Mother and sister are poly-substance abusers 3. Explain the most common signs and symptoms of acet- aminophen overdose. Vitals: Admission 4. Use patient information to design a pharmaceutical care Temp. HR BP RR plan for the treatment of acetaminophen overdose, includ- (°C) (beats/min) (mmHg) (breaths/min) ing rationale for treatment choices, administration instruc- tions, and appropriate monitoring parameters. 36° 101 144/89 15

Case Presentation Physical Examination  General: patient in some distress; looks older than stated age History of Present Illness  Skin: moist mucus membranes RG is a 27-year-old female (5'4" and 73 kg) presenting to the Emer-  Abdomen: bowel sounds present gency Department via EMS squad at 22:30. Earlier that evening, RG  Neurological: alert & oriented (A&O) x 3 and her mother had a heated argument. Shortly thereafter at 20:45, her mother called 911 after discovering RG in her bedroom with two Allergies/Adverse Drug Reactions open 100-count bottles of extra-strength acetaminophen (500 mg) on  Hydromorphone () the nightstand. The EMS squad counted 63 tablets remaining in the  Lisinopril (nausea) first bottle and found the second bottle empty. No other vi-  Nitroglycerin (muscle twitching) als were present in the bedroom. RG explained that she had taken only four acetaminophen tablets for a severe after the argument Labs: obtained at 22:35 with her mother. Currently, RG is complaining of nausea. Allergies Na 139 mmol/L Glu 4.3 µmol/L INR 1.0  None K 4.3 mmol/L Ethanol neg AST 41 U/L Past Medical History Cl 102 mmol/L Pregnancy neg ALT 36 U/L  Major Depressive Disorder x 9 years CO2 25 mmol/L APAP 132 µmol/L Alk Phos 77 U/L  History of suicidal gestures BUN 7.85 mmol/L THC pos T Bili 13.7 µmol/L  (IBS), predominant x 1 year SCr 53 µmol/L Albumin 38g/L  Sertraline 200 mg daily x 3 months  Lubiprostone 8 µg twice daily x 6 months

remington pharmed cases • march 2011 / case presentation: Soric, page 1 www.pharmpress.com/casestudies Assessment Questions 1. Describe the metabolism of acetaminophen, both at thera- peutic and toxic doses, and the effects of its metabolites on hepatocytes. 2. What are the most common signs and symptoms of acet- aminophen overdose? 3. List three risk factors for the development of liver injury or failure following a toxic ingestion of acetaminophen. 4. Approximately what single dose of acetaminophen is likely to cause toxicity in patients with no additional risk factors? 5. Design a pharmaceutical care plan for the treatment of RG’s acute condition. (answers on page 10)

Further Reading

1. Dart RC, et al. (1997). Acetaminophen (). In Dart RC, ed. Medical Toxicology. Philadelphia: Lippincott Williams and Wilkins, 723–738. 2. Dart RC, et al. (1997). N-Acetylcysteine. In Dart RC, ed. Medi- cal Toxicology. Philadelphia: Lippincott Williams and Wilkins, 223–227. 3. Dart RC, et al. (2006). Acetaminophen poisoning: an evidence- based consensus guideline for out-of-hospital management. Clin Toxicol 44: 1–18. 4. Rowden AK, et al. (2005). Updates on acetaminophen toxicity. Med Clin N Am 89: 1145–1159. 5. Wolf SJ, et al. (2007). Clinical policy: critical issues in the man- agement of patients presenting to the emergency department with acetaminophen overdose. Ann Emerg Med 50: 292–313.

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