Final answer:
A nurse should instruct a patient taking trimethoprim/sulfamethoxazole to avoid excess sunlight, drink 8 to 10 glasses of water daily, and be aware of drug interactions and sulfa allergies. The full course of the medication should be completed, regardless of symptom improvement.
Step-by-step explanation:
A nurse providing teaching to a patient prescribed trimethoprim/sulfamethoxazole should include several important instructions. Among these, it is crucial to advise the patient to avoid excessive sunlight due to the potential for photosensitivity reactions. Additionally, it is not necessary to take this medication on an empty stomach nor with a high-calcium beverage. The most important instruction that the nurse should emphasize is the need to drink 8 to 10 glasses of water daily to prevent the crystalluria that can occur with sulfonamides. It is also important for patients to be aware of possible drug interactions and sulfonamide allergies. Moreover, adherence to the full course of therapy is essential, even if symptoms improve before the medication is finished, to ensure the effective treatment of the infection and to prevent antibiotic resistance.