A 68-year-old woman is seen in the clinic for a 5-day history of diarrhea. The patient's stools are small, watery, and contain no blood or mucus. She has had no fever, dizziness, nausea, vomiting, or abdominal pain. Her other medical problems include hypertension, osteoporosis, gastroesophageal reflux, and stress incontinence. Several years ago, the patient had aortic valve replacement with a mechanical valve due to stenosis from a bicuspid aortic valve. Current medications include aspirin, amlodipine, alendronate, warfarin, and calcium and vitamin D supplements. The patient has not traveled recently or eaten anything unusual.
She is afebrile; blood pressure is 132/70 mm Hg and pulse is 78/min with no orthostatic changes. The remainder of the examination is within normal limits.
Laboratory results are as follows:
In addition to careful follow-up of INR, which of the following is the best next step in management of this patient?

Question

A 68-year-old woman is seen in the clinic for a 5-day history of diarrhea.  The patient's stools are small, watery, and contain no blood or mucus.  She has had no fever, dizziness, nausea, vomiting, or abdominal pain.  Her other medical problems include hypertension, osteoporosis, gastroesophageal reflux, and stress incontinence.  Several years ago, the patient had aortic valve replacement with a mechanical valve due to stenosis from a bicuspid aortic valve.  Current medications include aspirin, amlodipine, alendronate, warfarin, and calcium and vitamin D supplements.  The patient has not traveled recently or eaten anything unusual.
She is afebrile; blood pressure is 132/70 mm Hg and pulse is 78/min with no orthostatic changes.  The remainder of the examination is within normal limits.
Laboratory results are as follows:
 In addition to careful follow-up of INR, which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_983b_dc2a_853d_bd0b627693ab_MD0002_00 Patients on warfarin therapy are at risk for elevated INR due to drug interactions, vitamin K deficiency, and superimposed conditions (eg, diarrhea [odds ratio = 12.8], fever, liver disease, heart failure). Impaired cognition, depression, or low literacy can also lead to elevated INR due to incorrect warfarin dosing. The initial approach to elevated INR depends on the following: Degree of elevationPresence of active bleedingPatient's bleeding riskIndications for continued warfarin therapy after the episode resolves Degree of elevation Presence of active bleeding Patient's bleeding risk Indications for continued warfarin therapy after the episode resolves Patients with INR <4.5 who have no significant bleeding can be managed by holding warfarin for 1-2 doses and/or slightly reducing the maintenance dose (Choices D and E). INR 4.5-10 is managed similarly if no bleeding is present; those with increased bleeding risk (eg, older age, history of bleed) may also be treated with low-dose oral vitamin K. Patients with INR >10 who have no concurrent bleeding require temporary warfarin cessation and high-dose oral vitamin K (as risk for major bleed is 10%-20%). Oral vitamin K is preferred as it is as effective as intravenous (IV) vitamin K in lowering INR within 48 hours and is associated with a lower risk of anaphylaxis. (Choices B and C) Serious or life-threatening bleeding at any INR requires holding warfarin and immediate INR reversal with slow IV vitamin K infusion, fresh frozen plasma, or IV prothrombin complex. Educational objective: Supratherapeutic INR <4.5 without significant bleeding can be managed by holding warfarin. INR 4.5-10 is managed similarly if no bleeding is present; those with increased bleeding risk may also be treated with low-dose oral vitamin K. INR >10 requires temporary warfarin cessation and high-dose oral vitamin K. Life-threatening or serious bleeding with any INR requires holding warfarin and immediate INR reversal (eg, intravenous vitamin K, prothrombin complex concentrate). __________ References: Pharmacology and management of the vitamin K antagonists. American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). (http://www.ncbi.nlm.nih.gov/pubmed/18574265) Evidence-based management of anticoagulant therapy: antithrombotic therapy and prevention of thrombosis, 9th ed. American College of Chest Physicians evidence-based clinical practice guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/22315259)

A 68-Year-Old Woman Is Seen in the Clinic for a 5-Day