Acetaminophen hemolytic anemia with

Variations on the molecular structures have provided improved side effect profiles of agents used. For example, although phenacetin and acetaminophen are not anti-inflammatory agents, they are included in this chapter, because they are analgesics and antipyretics and illustrate the point that improvement in molecular structure from phenacetin to acetaminophen helped to reduce the hepatotoxicity and risk for drug-induced hemolytic anemia with which phenacetin was associated when it was on the market in the past. 

Acetaminophen causes few adverse reactions when used as directed on the label or recommended by the primary health care provider. Adverse reactions associated with the use of acetaminophen usually occur with chronic use or when the recommended dosage is exceeded. Adverse reactions to acetaminophen include skin eruptions, urticaria (hives), hemolytic anemia, pancytopenia (a reduction in all cellular components of the blood), hypoglycemia, jaundice (yellow discoloration of the skin), hepatotoxicily (damage to the liver), and hepatic failure (seen in chronic alcoholics taking the drug). 

Hemolytic anemia and methemoglobinemia, reported with the use of phenacetin, are rarely noted with acetaminophen. Interstitial nephritis and papillary necrosis—serious complications of phenacetin—although anticipated with widespread chronic use of acetaminophen, have not occurred. Gastrointestinal bleeding does not occur. Caution should be exercised in patients with liver disease. 

Oxidative damage to hemoglobin may lead to its precipitation (e.g., by acetaminophen) and present as Heinz bodies that can be detected by morphological evaluation of blood smears. Heinz body is a rounded, often retractile, projection from the surface of the RBC that is due to oxidation and denatur-ation of hemoglobin. Typically, the detection of Heinz bodies associated with hemolytic anemia is believed to be indicative of nonimmune-mediated anemia. In contrast, supportive evidence of the involvement of immune system components in anemic animals could include a positive autoagglutination of blood cells. 

Hemolytic anemia after acetaminophen overdose in patient with glucose-6-phosphate dehydrogenase deficiency. 

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