You observe changes in mentation, irritability, restlessness, and decreased concentration in a patient with cancer of the liver. Hepatic encephalopathy is suspected and the patient is ordered neomycin enemas. Which of the following information in the patient’s history would be a contraindication of this order?
A. Left nephrectomy
B. Glaucoma in both eyes
C. Myocardial infarction
D. Peripheral neuropathy
Correct Answer: A. Left nephrectomy
Neomycin prevents the release of ammonia from the intestinal bacteria flora and from the breakdown of red blood cells. Common side-effects of this drug are nephrotoxicity and ototoxicity. Patients with renal disease or renal impairment should not take this drug. A baseline serum BUN/creatinine should be obtained with subsequent periodical follow-up blood tests during chronic therapy to monitor for effects on renal function. Prompt discontinuation of the drug should occur with any signs of renal or otologic damage.
Option B: Glaucoma is not affected by neomycin. Neomycin belongs to a group of antibiotics known as aminoglycosides. Like others in the aminoglycoside family, neomycin works by inhibiting bacterial protein synthesis leading to its bactericidal effect. This group of medications is particularly effective in killing gram-negative organisms allowing for good coverage of enteric organisms.
Option C: MI is not affected by neomycin. Neomycin’s mechanism of action is very similar to most aminoglycosides as it binds to the 30s ribosomal subunit interfering with bacterial protein synthesis. This action thereby disrupts the process of translation by bacteria leading to the medication’s bactericidal effects.
Option D: Peripheral neuropathy is a chronic complication of diabetes mellitus. Neomycin’s bactericidal effects decrease ammonia-producing bacteria residing in the GI tract, thereby decreasing the burden of ammonia on the patient. Neomycin is often reserved for patients that cannot tolerate rifaximin.
No comments:
Post a Comment