Final answer:
A 62-year-old female with impaired renal function is likely to experience hyperkalemia when treated with sulfamethoxazole/trimethoprim for a urinary tract infection, due to the drug's impact on potassium balance and the patient's decreased kidney function.
Step-by-step explanation:
The 62-year-old female with impaired renal function who was prescribed sulfamethoxazole/trimethoprim for a urinary tract infection is likely to experience hyperkalemia. Sulfamethoxazole/trimethoprim therapy can cause hyperkalemia, especially in patients with underlying kidney dysfunction, due to the drug's ability to inhibit the renal excretion of potassium. Patients with renal impairment are at a greater risk for this electrolyte disorder because their kidneys are less capable of maintaining potassium balance. This is compounded by the fact that trimethoprim acts in a similar way to potassium-sparing diuretics, leading to increased potassium levels.
Monitoring electrolyte levels, especially potassium, is crucial in patients with renal impairment receiving sulfamethoxazole/trimethoprim. The combination of trimethoprim and sulfamethoxazole, used to treat infections like urinary tract infections, can potentiate this risk of hyperkalemia due to the inhibition of renal tubular secretion of potassium exacerbated by impaired renal function.