When providing teaching for trimethoprim/sulfamethoxazole, which instruction should a nurse emphasize?

The emphasis on drinking 8 to 10 glasses of water daily when taking trimethoprim/sulfamethoxazole is rooted in the medication's potential to cause crystalluria, a condition where crystals form in the urine, which can lead to kidney damage. Maintaining adequate hydration helps dilute the urine, reducing the concentration of the drug and minimizing the risk of these crystals forming. This is especially important because both components of the medication can impact renal function, and proper hydration is a simple preventive measure to protect the kidneys and enhance drug excretion.

While taking the medication with food can help minimize gastrointestinal upset, it is not as critical as ensuring adequate fluid intake. Similarly, while a fine, red rash can occur as a side effect of this medication, not all patients will experience this, and it does not warrant a routine warning. Storing the medication in the refrigerator is not necessary; it should typically be kept at room temperature. Emphasizing hydration reinforces the need for patient safety and effective medication management.