What medications require regular assessment of blood clotting parameters, such as complete blood counts, platelet function tests, and coagulation studies like prothrombin time (PT) and partial thromboplastin time (PTT), when taken regularly by a patient, including Nonsteroidal anti-inflammatory drugs (NSAIDs) and Salicylates (aspirin)?

From the Guidelines

Medications that require regular assessment of blood clotting parameters include Salicylates (aspirin) and Nonsteroidal anti-inflammatory drugs (NSAIDs), due to their antiplatelet effects and potential to increase bleeding risk. When considering the medications listed, the following require regular monitoring of blood clotting parameters:

• Salicylates (aspirin) 1
• Nonsteroidal anti-inflammatory drugs (NSAIDs) 1 These medications can affect platelet function and increase the risk of bleeding, particularly when used in combination with anticoagulants 1. Key points to consider when monitoring blood clotting parameters in patients taking these medications include:
• Regular assessment of complete blood counts and platelet function tests
• Monitoring of coagulation studies, such as prothrombin time (PT) and partial thromboplastin time (PTT)
• Increased risk of bleeding when combined with anticoagulants, requiring careful monitoring and potential adjustments to medication dosages 1
• Importance of monitoring in patients with existing bleeding disorders, renal impairment, or those taking multiple medications affecting coagulation 1.

From the FDA Drug Label

Warnings Stomach bleeding warning: This product contains an NSAID, which may cause severe stomach bleeding The chance is higher if you are age 60 or olderHave had stomach ulcers or bleeding problemsTake a blood thinning (Anticogulant) or steroid drugTake other drugs containing prescription or nonprescription NSAIDs (aspirin, ibuprofen, naproxen, or others)have 3 or more alcoholic drinks every day using this product

The medications that require regular assessment of blood clotting parameters are:

• Salicylates (aspirin): due to the risk of stomach bleeding and interaction with blood thinning (anticoagulant) drugs 2
• Nonsteroidal anti-inflammatory drugs (NSAIDs): as they may cause severe stomach bleeding, especially when taken with other NSAIDs, anticoagulants, or steroids 2

From the Research

Medications Requiring Regular Assessment of Blood Clotting Parameters

The following medications require regular assessment of blood clotting parameters, such as complete blood counts, platelet function tests, and coagulation studies like prothrombin time (PT) and partial thromboplastin time (PTT), when taken regularly by a patient:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) 3, 4
• Salicylates (aspirin) 3, 4, 5
• Acetaminophen 3

Mechanism of Action

These medications affect platelet function and blood clotting parameters in different ways:

• Aspirin irreversibly inhibits platelet-dependent thromboxane formation by acetylation of the platelet cyclooxygenase (COX) enzyme 5
• NSAIDs, particularly nonselective formulations, can decrease platelet aggregation 3, 4
• Acetaminophen can decrease platelet aggregation, although the mechanism is not fully understood 3

Laboratory Tests

Various laboratory tests are available to assess platelet function and blood clotting parameters, including:

• Platelet function analyzer (PFA-100) 4, 6
• Light transmission platelet aggregation 6
• Lumiaggregometry 6
• Impedance aggregometry on whole blood 6
• Flow cytometry to investigate platelet activation 6