Overcoming multidrug resistance: valspodar as a paradigm for nursing care.

To review the mechanisms of multidrug resistance (MDR) in human cancer and the clinical use of MDR modulators to overcome or reverse P-glycoprotein (P-gp)-mediated MDR. Current literature, ongoing clinical trials, and clinical experience. Agents, such as valspodar, that block the activity of P-gp can reverse or overcome MDR caused by overexpression of P-gp. The MDR modulator valspodar (PSC 833; Novartis Pharmaceuticals Corporation, East Hanover, NJ) is examined as a model for establishing nursing guidelines for this new class of therapeutic agents. The dose of some chemotherapy agents must be modified with concurrent valspodar administration. Studies examining the safety and efficacy of valspodar as a prototype of MDR modulators provide the basis for establishing nursing care guidelines. Nursing care for the administration of valspodar includes understanding patient selection, criteria, dosing, and administration; side-effect management; patient monitoring and follow-up; and patient education.