NSAID.

155 Warfarin therapy is considered a relative contraindication to NSAID use.

In patients like G.H., routine use of NSAIDs with long-term anticoagulation should

be avoided. Any patients requiring combined warfarin and NSAID therapy for

limited periods of time should be followed closely and observed routinely for signs

and symptoms of bleeding, with frequent stool testing for GI bleeding. Patients should

be counseled to avoid additional NSAID use whenever possible, including use of

aspirin, and to seek assistance from a pharmacist to prevent inadvertent NSAID use

when selecting over-the-counter (OTC) medications, as some OTC cold preparations

contain NSAIDs, aspirin, or aspirin-related compounds.

The analgesic and antipyretic of choice in patients taking warfarin is

acetaminophen, which has not been consistently shown to increase the risk of

bleeding. At doses greater than 2 g/day, acetaminophen can enhance the anticoagulant

effect of warfarin.

156

It has been suspected of directly inhibiting CYP2C9 and

CYP1A2, and toxic metabolites of acetaminophen have been suspected of inhibiting

hepatic enzymes as well. Nevertheless, it can be used safely when used occasionally,

and even when used routinely. INR monitoring is sufficient to detect any potential

interaction. Other pain-relieving options to be considered that do not increase the

bleeding risk include tramadol, gabapentin, pregabalin, topical lidocaine patches,

and opiates.

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