Final answer:
The nurse should question the healthcare provider about the client's use of aspirin combined with warfarin due to the increased risk of bleeding, as both are anticoagulant medications.
Step-by-step explanation:
The home health nurse should question the healthcare provider about the client's use of aspirin while having a new prescription for warfarin. Warfarin is an anticoagulant medication that works to prevent blood clots by decreasing the blood's ability to clot. Aspirin, also an antiplatelet, can increase the risk of bleeding when used in combination with warfarin. This is because both drugs work to prevent clot formation, albeit through different pathways, but when used together, they greatly enhance the anticoagulant effect, increasing the chance of bleeding, which may be severe.
Nifedipine is a calcium channel blocker used primarily for hypertension and would not typically alter warfarin's effects. NPH insulin is used for diabetes management and does not have a known interaction with warfarin. A vitamin D supplement has no significant effect on warfarin's action, although vitamin K supplements should be avoided since they can decrease the effectiveness of warfarin.