Which instruction should a nurse provide to a client receiving sulfisoxazole?

Maintaining a high fluid intake while receiving sulfisoxazole is important because this medication can lead to the formation of crystals in the urine. Increased fluid intake helps to dilute the urine and promote adequate kidney function, thereby reducing the risk of crystalluria and potential urinary tract complications. Staying well-hydrated ensures that the kidneys can effectively process and eliminate the medication and any byproducts, ultimately helping to minimize the risk of side effects and improve the overall efficacy of the treatment.

In contrast, restricting fluid intake could lead to more concentrated urine, which increases the likelihood of crystal formation and urinary tract issues. Monitoring changes in urine color is relevant for assessing kidney function, but dark brown urine is not solely an indication that requires immediate medical attention without further context. Additionally, the dosage should not be decreased arbitrarily based on symptom improvement, as this may lead to inadequate treatment and increased risk of antibiotic resistance instead of preventing allergic responses.