coagulation counseling

Anna D. Garrett, PharmD, BCPS, CPP
Published Online: Sunday, June 1, 2008
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Dr. Garrett is manager of the Health Education Center, Mission Hospitals, Asheville, North Carolina.


FDA APPROVES UPDATE TO LABEL ON BIRTH CONTROL PATCH

The FDA has approved new changes to the Ortho Evra Contraceptive Transdermal Patch label to include the results of a new epidemiology study that found that users of the birth control patch were at higher risk of developing venous thromboembolism (VTE) than women using birth control pills.

The FDA initially revised the label for Ortho Evra, which is applied once a week, in September 2006 to warn women of the risk of VTE based on 2 epidemiology studies. One study, conducted by i3 Ingenix, showed that some women using the patch were at a twofold greater risk of developing VTE. The other study, conducted by the Boston Collaborative Drug Surveillance Program, showed that women using the patch were not at increased risk, compared with women using birth control pills containing 30 to 35 mcg of estrogen and the progestin norgestimate.

Transdermal delivery of estrogen exposes women to about 60% more estrogen than typical birth control pills. Increased levels of estrogen may increase the risk of side effects, including VTE. Women should discuss the possible increased risk of VTE with Ortho Evra with their health care provider and balance this risk against the increased chance of pregnancy if they do not take a daily birth control pill. Women with a high risk of VTE (such as those over age 40, those who smoke, etc) may wish to consider other methods of birth control.


CONTINUOUS ENTERAL NUTRITION CAUSES WARFARIN RESISTANCE

A small retrospective crossover study of patients requiring continuous enteral nutrition in the intensive care unit of an academic medical center showed international normalized ratio (INR) changes when warfarin was coadministered with the enteral feedings. The study included 6 adults who required nutritional support for at least the first 10 consecutive days of warfarin therapy. During the 10-day period, enteral feedings were withheld for 1 hour before and after warfarin administration. The patients then crossed over to a 3-day period where feedings were not withheld around warfarin administration.

The change in INR during the period when feedings were withheld was significantly different versus the change in INR during coadministration of warfarin with continuous feeding (-0.13). The authors concluded that continuous enteral nutrition should be withheld for 1 hour before and after warfarin administration to prevent enteral nutrition?associated warfarin resistance. Further study is warranted to explain the warfarin resistance.


MEDICARE EXPANDS COVERAGE OF HOME INR MONITORING

The Centers for Medicare & Medicaid Services recently approved expanded coverage for home international normalized ratio (INR) testing. New indications for home testing include chronic atrial fibrillation and deep vein thrombosis. Previously, coverage was available only for patients with artificial heart valves. To qualify for home testing, patients will need to be anticoagulated for at least 3 months prior to use of the home testing device, undergo face-to-face education regarding anticoagulation management, demonstrate use of the device, continue to use the device correctly, and undergo testing no more than once a week.

Studies indicate that warfarin is underused for a significant portion of patients who may benefit. Expansion of coverage may help increase appropriate use and improve the amount of time patients spend in the therapeutic range.


LMWH ASSOCIATED WITH REDUCED VTE COSTS

Results of a recent study demonstrated that total hospital direct medical costs associated with venous thromboembolism (VTE) treatment were reduced by $550 for patients when they were treated with low-molecular-weight heparin (LMWH), compared with unfractionated heparin (UFH). Patients who received LMWH also were less likely to be readmitted to the hospital with a VTE recurrence within 90 days.

The study was a retrospective cohort study examining 38,664 patient discharges from January 2003 through June 2005. Patients had a primary diagnosis of VTE and were treated with either LMWH or UFH. The average length of hospital stay for the UFH group was 1.1 days longer (5.7 days vs 4.6 days). After adjustment for covariates, the average total direct hospital costs were $3618 for UFH and $3068 for LMWH. Anticoagulation therapy costs were higher for LMWH ($242 vs $41 for UFH). LMWH was associated with lower rates of VTE-related readmission at both 30 and 90 days. The authors concluded that, despite higher drug-related costs for LMWH, the total direct medical cost for the treatment of VTE is reduced, when compared with using UFH.



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