Home injects for angina, non-Q-wave patients?
Unsupervised injections are in the pipeline
Patients with coronary artery disease (CAD) and recurrent chest pain - non-Q-wave myocardial infarction (MI) - may soon be able to self-inject the low-molecular-weight heparin (LMWH) enoxaparin (Fort Washington, PA-based Rhone-Poulenc Rorer's Lovenox) at home to prevent the onset of a second heart attack. A study originating in France showed that injections of enoxaparin lowered reactant protein levels to a greater degree than did heparin.1 The study was part of the 3,000-participant multicenter ESSENCE (Effectiveness and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events) clinical trial. Only one in four patients on the drug had a heart attack or chest pain within two weeks, compared with half who were given heparin. The results were similar at one month.
Patients have been self-administering enoxaparin for years to prevent deep vein thrombosis (DVT) following hip and knee replacement surgery and high-risk abdominal surgery. For that indication, patients are instructed to inject 30 mg subcutaneously into the abdomen twice a day for one to 14 days. Bleeding, bruising, irritation, pain or redness at the injection site, nausea, fever, and confusion are all possible side effects of enoxaparin for DVT prophylaxis. Patients are instructed to rotate sites and not to massage the site after injection. Aspirin is to be avoided for that indication.
"The problem with Lovenox is that it's an expensive drug, and many insurance companies don't cover its cost," says Kimberly Bell, RN, CCRN, nurse clinician for the coronary care unit and coronary progressive care unit at St. Francis Hospital and Health Centers in Beech Grove, IN. "Our patients will leave with prescriptions for it, and we do all the education on self-injection, but when they get to their pharmacies, they find out the drug's not covered by their insurance, so they don't fill the prescription." Once clinicians at St. Francis became aware of that problem, care managers and the discharge staff started checking ahead of time with insurers to find out if the enoxaparin was covered, so they could tell the patient what cost they were going to be faced with. "We have a program set up with our pharmacy so that they will dispense the drug to patients, bill them, and accept scheduled payments for it. That makes it easier on the patients," adds Bell.
In March, the Food and Drug Administration approved the in-hospital use of Lovenox for preventing ischemic complications of unstable angina and non-Q-wave MI when the drug is administered concurrently with aspirin. The cost of Lovenox for inpatient injection is $60 per day. Rhone-Poulenc is just now applying for an approval for self-administered injection of the drug for acute coronary indications.
Drugs restore blood flow
A study from investigators at Duke University Medical Center in Durham, NC, found $1,100 per patient cost savings with the use of enoxaparin plus aspirin when compared with the standard treatment of heparin plus aspirin.2 That study also was an offshoot of the ESSENCE trial. Patients in both the enoxaparin and standard groups received daily aspirin at a dose of 100-325 mg. Among more than 900 American patients with unstable angina or non-Q-wave MI, total costs for initial hospitalizations averaged $11,857 for those on enoxaparin and $12,620 for those on heparin, a $763 savings. Over 30 days the cumulative savings for enoxaparin was $1,172. The cost savings were achieved through shorter hospital stays, lowered physician fees, and a reduction in invasive procedures such as diagnostic catheterizations and angioplasties.
Enoxaparin, a "slimmed-down" version of heparin, helps stifle clot-forming reactant proteins - the von Willebrand factor - that enter the bloodstream in response to injury. Levels of von Willebrand factor increase dramatically over the first 48 hours following heart attack or an episode of chest pain, and both heparin and enoxaparin act to shut off the mechanism, restoring blood flow to the heart.
Enoxaparin should not be administered to patients with known hypersensitivity to heparin or pork products or a history of heparin-induced thrombocytopenia.
References
1. Montalescot G, Philippe F, Ankri A, et al, for the French Investigators of the ESSENCE Trial. Early increase of Von Willebrand Factor predicts adverse outcome in unstable coronary artery disease: Beneficial effects of enoxaparin. Circulation 1998;98:294-299; Antman EM, Handin R. Low-molecular-weight heparins: An intriguing new twist with profound implications. Circulation 1998;98:287-289.
2. Mark DB, Cowper PA, Berkowitz SD, et al. Economic assessment of low-molecular-weight heparin (enoxaparin) versus unfractionated heparin in acute coronary syndrome patients: Results from the ESSENCE randomized trial. Circulation 1998;97:1702-1707.
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