R.Ph.S Can Ensure Prophylaxis of Patients at Risk for DVT
Bredensteiner, Sue, Drug Topics
Consultant pharmacists can play a vital role in preventing deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT and PE comprise a major cause of morbidity and mortality in the United States, with an estimated 300,000 to 600,000 hospitalizations annually and 100,000 deaths per year from pulmonary embolism. This makes PE the thirdleading cause of hospitalized patients' deaths-behind cardiovascular diseases and cancer.
Most DVTs are asymptomatic. Unrecognized or untreated, DVr can lead to PE-often a diagnosis of death-or to chronic postphlebitic syndrome (PPS) and recurrent DVT. In the changing health-care environment-the increasingly aging population, cost-containment pressures, earlier hospital discharge, substandard prophylaxis, and uncertain optimum prophylactic duration-the consultant pharmacist must be prepared to prevent development of DVT/PE.
That was the message that Richard C. Smith, Pharm.D., FASCP, clinical pharmacist at the ICU/Cardiac Care Center, Green Hospital at Scripps Clinic, Lajolla, Calif., drove home to attendees at a session of the American Society of Consultant Pharmacists' annual meeting in Nashville recently. The session was sponsored by Rhone-Poulenc Rorer Pharmaceuticals.
According to Smith, clinical signs and symptoms for DVT/PE are nonspecific, with Doppler ultrasound or venography the only definitive diagnosis. Patients at risk for the condition may have experienced recent hospitalization, previous diagnosis of DVT/PE, immobility, malignancy, obesity, general anesthesia, major surgery over 30 minutes, orthopedic surgery of the lower extremity, major trauma, myocardial infarction, estrogen therapy, varicose veins, stroke/paralysis, or hypercoagulability.
"The perfect prophylactic modality is safe, effective, inexpensive, easy to use, easy to monitor-and does not exist as yet for DVT," Smith said. He emphasized that a combination of mechanical compression devices and pharmacologic methods has proven effective. Pharmacologic modalities include aspirin, warfarin (Coumadin), low-dose or adjusted-dose heparin, and low molecular weight heparin (LMWH). Of these, the LMWHs are the most promising for moderateand higher-risk patient groups.
However, all LMWHs are not alike, nor are they interchangeable, Smith cautioned. Each has its own dosing, pharmacokinetics, and indications, he said. Numerous LMWHs have been used in Europe for more than 10 years and have shown predictable dose response, high bioavailability, limited interindividual variability, and linear pharmacokinetics. Unfortunately, he added, only two of them, enoxaparin and dalteparin, have been approved by the Food & Drug Administration for use in the United States.
In the absence of the perfect treatment, Smith described a gold standard guide developed by the Fourth American College of Chest Physicians (ACCP) Consensus Conference on Antithrombotic Therapy in October 1995. …