Ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), can increase the risk of bleeding in patients taking warfarin by both affecting platelet function and irritating the gastrointestinal lining.

• Acetaminophen is generally safer for pain relief in warfarin patients (though high doses over time can still affect INR).

• Loratadine is an antihistamine with no significant effect on bleeding risk.

• Metformin is an antidiabetic medication unrelated to coagulation.

Controlled substance records must be maintained and be readily retrievable for inspection.

Schedule III and IV prescriptions may be refilled up to 5 times in 6 months under federal law; Schedule V is often governed differently depending on the substance and product, but this is the classic federal refill rule tested for III-IV.