When a client is on warfarin, which statement indicates the need for further teaching?

When a client is on warfarin, the statement indicating the need for further teaching is one that underestimates the complexities and potential interactions associated with over-the-counter medications. Warfarin is an anticoagulant that requires careful management due to its interactions with a wide variety of substances, including certain over-the-counter drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs), some herbal supplements, and even vitamins. These interactions can either enhance the effects of warfarin, increasing the risk of bleeding, or reduce its effectiveness, increasing the risk of thrombosis.

Therefore, the correct statement highlights the importance of consulting with a healthcare provider before taking any over-the-counter medications. Understanding that these medications may affect INR levels or interact negatively with warfarin is crucial in ensuring safe and effective treatment. The other statements reflect appropriate knowledge regarding warfarin therapy, emphasizing consistent vitamin K intake, the need to avoid alcohol, and the importance of routine INR monitoring to assess warfarin's effectiveness and adjust dosages as necessary.