Pharmacy & Therapeutics - February 2008 - (Page 110)

Management of Acute Venous Thromboembolism are also in the early stages of developing and possibly implementing inpatient warfarin monitoring that will result in uniform procedures across the entire continuum of care. No. of Patients Because of a recent history of sigMajor Bleeding Non-bleeding nificant bleeding or major bleeding Variable of Interest (n = 20) (n = 101) P Value shortly after anticoagulation therapy was initiated, nine patients (6%) Past medical history never started warfarin. We had iniHeart failure 2 15 0.5684 tially attempted to evaluate whether Cerebrovascular accident 0 10 0.1418 a longer duration of warfarin therCancer 10 29 0.0627 apy was associated with an inAge > 65 years 12 60 0.9606 creased risk of major bleeding. Of INR > 3 at time of bleeding 5 0 65 years 11 79 0.4422 the duration of warfarin therapy Duration of warfarin therapy ≤3 months 4 36 0.3946 might not always be what influences INR < 1.8 when heparin was discontinued 13 89 0.5185 the increased risk of major bleedINR = International Normalized Ratio. ing; instead, the presence of major bleeding may be what dictates the duration of warfarin therapy. Because the risk of bleeding is common when patients begin • The INR was below 1.9 in 19.3% of patients when heparin anticoagulation therapy, adequate monitoring of pertinent labwas discontinued. oratory values, concomitant medications, and individual patient • An inappropriate initial dose of UFH was prescribed for characteristics is essential. 45% of the patients. The most recent ACCP guidelines recommend that war• The duration of heparin therapy was inappropriate in 40% farin be continued for a minimum of three months in patients of our patients (the mean duration was seven days, and with a first episode of VTE because of a known and reversible 40% remained on heparin therapy for less than five days). risk factor such as immobility. However, if the VTE is idio• Because of multiple comorbidities among our study subpathic, patients should continue taking warfarin for a minimum jects, we could not establish whether the duration of warof six months if no other risk factors for VTE are present. farin therapy was appropriate. Patients with recurrent VTE should be considered for indefinite anticoagulation therapy.3 Thirty-two patients (21.3%) In order to minimize inappropriate dosing of UFH, our facility has developed a standardized heparin protocol order set continued warfarin therapy for three months or less; 41% of that automatically incorporates the patient’s most recent these patients were treated for an idiopathic VTE. Another 28 weight; in addition, the pharmacy now double-checks all patients (18.7%) continued taking warfarin for three months or heparin doses. The development of a nursing weight-based more but for six months or less. Forty-eight patients (32%) heparin protocol has streamlined infusion rate adjustments and were being treated for a first-time DVT and/or PE, and they the intricate monitoring associated with this medication. continued with warfarin for more than six months of therapy. According to the 2004 guidelines from the American College Of these patients, however, only 18 (37.5%) had a documented of Chest Physicians (ACCP), the recommended starting dose risk factor of a hypercoagulable state at the time of the VTE. of warfarin needed to achieve a therapeutic INR is 5 to 10 mg. The target duration of warfarin therapy, now incorporated If the patient is elderly or frail or has heart failure, a high risk as a parameter in our initial anticoagulation consult template, of bleeding, or underlying liver disease, the recommended is monitored by the outpatient anticoagulation clinic. Because starting dose is 5 mg/day or less.5 anticoagulation therapy is a complex and high-risk treatment necessitating extensive patient commitment, the duration of If the baseline INR is already elevated, based on clinical practherapy should be minimized to maintain an appropriate baltice experience, we would start these patients at lower initial ance in which the benefits always outweigh the risks. warfarin doses of less than 5 mg. Most of our patients started Our secondar y objective was to identify differences in warfarin at a dose of 5 mg or 7.5 mg daily, although 21 patients patient characteristics or management strategies that led to a (14%) received 10 mg of warfarin initially. recurrence of VTE or bleeding. When we compared various A pharmacist reviews all inpatient medication profiles on factors, the only significant difference between the major admission in order to identify discrepancies and to recombleeding and non-bleeding groups was an INR above 3 at the mend improvements in dosing including warfarin dosing. We Table 3 Comparisons of Major Bleeding with Non-bleeding And of Recurrence with Non-recurrence continued on page 117 110 P&T® • February 2008 • Vol. 33 No. 2

Table of Contents Feed for the Digital Edition of Pharmacy & Therapeutics - February 2008

Pharmacy & Therapeutics - February 2008 Contents Editorial Medication Errors Prescription: Washington The Language of (Forgive Us) Change, As P&T Enters the Digital Age New Drugs/Drug News/New Medical Devices Drug Forecast Use and Outcomes of Antifibrinolytic Therapy in Patients Undergoing Cardiothoracic Surgery at 20 Academic Medical Centers in the United States Evaluation of the Management of Acute Venous Thromboembolism and Its Outcomes: One Institution's Experience American Society of Hematology, 49th Annual Meeting Pharmaceutical Approval Update

Pharmacy & Therapeutics - February 2008

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