An 87-year-old woman comes to the office to discuss treatment for colon cancer, which was recently diagnosed by colonoscopy. CT scan was negative for metastatic disease. The patient has no other medical conditions, and family history is unremarkable. She does not drink alcohol. Vital signs are normal. A chemotherapy regimen containing a medication that is primarily metabolized by the liver is chosen for therapy. Because of the patient's age, the physician is considering adjusting the dose to prevent adverse effects. Which of the following parameters is likely to be the most similar between this patient and a healthy 40-year-old individual?

Question

An 87-year-old woman comes to the office to discuss treatment for colon cancer, which was recently diagnosed by colonoscopy.  CT scan was negative for metastatic disease.  The patient has no other medical conditions, and family history is unremarkable.  She does not drink alcohol.  Vital signs are normal.  A chemotherapy regimen containing a medication that is primarily metabolized by the liver is chosen for therapy.  Because of the patient's age, the physician is considering adjusting the dose to prevent adverse effects.  Which of the following parameters is likely to be the most similar between this patient and a healthy 40-year-old individual?

Quizplus · Accepted Answer

11ec160b_3cbf_d9ff_9249_efbb79c6d4c5_MD0001_00 A number of age-related changes take place in the liver that impair its ability to metabolize drugs. These changes place elderly individuals, such as this patient, at higher risk for drug-related toxicity. Normal age-related changes include the following: Decreased liver mass, which is largely explained by the decrease in hepatic blood flow that occurs with aging, can impair metabolism because the liver is unable to take up as much drug from the systemic circulation as it once could. Decreased cytochrome P-450 expression and concentration slows the rate of hepatic metabolism of numerous drugs (eg, some antineoplastic agents). Reduced rate of hepatic regeneration impairs the liver's ability to recover after injury. Although the liver's metabolic capabilities generally decline with age, aminotransferase levels are unchanged in healthy elderly individuals. Elevations in liver enzymes should therefore raise suspicion for undiagnosed hepatic disease or hepatotoxin exposure. Small variations may be seen in bilirubin, alkaline phosphatase, and gamma-glutamyltransferase levels, but they are generally minimal. (Choices A, B, C, and E) Concentration of cytochrome P-450 and the liver's perfusion, regenerative capabilities, and size are all decreased in the elderly compared to younger individuals. Educational objective: A number of changes occur in the liver with aging that can affect drug metabolism. Typical changes include decreased liver mass and blood flow, decreased cytochrome P-450 expression and concentration, and reduced hepatic regeneration after injury. However, hepatic aminotransferase levels are unchanged. __________ References: Liver physiology and liver diseases in the elderly. (http://www.ncbi.nlm.nih.gov/pubmed/24379563)

An 87-Year-Old Woman Comes to the Office to Discuss Treatment