A patient who has unrelenting bone pain as a result of metastatic cancer contracts an infection requiring treatment with nafcillin. Which nursing intervention can help decrease the needed dosage of nafcillin?

Nafcillin, like other penicillins, is an antibiotic whose activity can be enhanced when used alongside NSAIDs. NSAIDs such as aspirin or indomethacin compete with penicillins for protein-binding sites and reduce renal tubular secretion of the antibiotic. When renal secretion is slowed, plasma levels of nafcillin remain elevated for longer periods, allowing a lower dose to achieve the same therapeutic effect. This pharmacokinetic interaction is clinically useful in patients where minimizing drug load is beneficial, such as those with serious illness like metastatic cancer. Providing a high-calorie, high-protein diet supports overall nutritional status and healing but does not directly affect nafcillin dosing or pharmacokinetics. Maintaining fluid volume is important for renal perfusion and preventing toxicity but would actually promote renal clearance of the drug rather than reducing required dosage. Infusing the antibiotic as quickly as allowed does not affect the total dose needed and could increase the risk of adverse effects. The NSAID option correctly addresses the pharmacokinetic mechanism by which drug levels can be sustained at lower doses, making it the most appropriate nursing intervention in this context. Students should remember that drug-drug interactions involving protein binding and renal secretion can meaningfully alter medication pharmacokinetics and clinical dosing strategies.