Show #20, October 2003
Show #20, October 2003
|New Test to Help Predict CHD|
The FDA has cleared for marketing a new lab test that will help establish a patient's risk for coronary artery disease. The test is called PLAC, and it's manufactured by diaDexus, Inc. It works by measuring serum levels of an enzyme that's manufactured by macrophages, called lipoprotein-associated phospholipase A2. Elevated levels of this enzyme correlate with an increased risk of coronary artery disease.
This test is not intended to replace existing lab measurements such as total cholesterol, LDL and triglycerides. It simply adds information to help evaluate a patient’s risk. And it’s not intended to be used by itself. It provides supportive information when it’s used in conjunction with a clinical evaluation and an appraisal of other blood tests and risk factors.
Studies of the PLAC test have shown it to be most useful in patients who have relatively low levels of low-density lipoprotein, the so-called “bad cholesterol.”
The test was cleared based on a study of blood samples collected from over 1,300 patients over a nine year period. Among patients with an LDL level below 130 mg/dL, those who had a high PLAC level experienced two to three times the risk of coronary artery disease than those with a low PLAC level.
Essentially, the PLAC test represents a new tool to help assess heart disease risk, but it should be used along with other tools.
|Photodynamic Therapy for Barrett’s Esophagus Patients|
FDA recently approved a new use for the photosensitizing agent Photofrin: ablating high grade dysplasias in patients with Barrett's esophagus who don’t undergo esophagectomies. Photofrin, also called porfimer sodium, is distributed by Axcan Scandipharm. It was previously approved to treat several types of cancers as part of photodynamic therapy.
During photodynamic therapy, Photofrin is injected into the patient, where it's initially absorbed by body tissues. Over the next couple of days, the drug will largely be eliminated from most healthy tissues, but remain in abnormal cells. Using an endoscope, laser light is then delivered by fiber optic to the treatment area. The Photofrin in the abnormal cells absorbs the laser light rays and sets off oxygen radicals, which kill the cells while limiting damage to surrounding healthy tissue.
The clinical study supporting this new use of Photofrin photodynamic therapy showed that patients receiving this treatment were more likely to achieve complete reversal of their precancerous lesions in Barrett’s esophagus compared to controls. Two-year follow-up data from this clinical study showed that patients receiving this therapy had an 80% chance of being cancer-free, while control patients had a 50% chance of being cancer-free. The effectiveness of Photofrin PDT in reducing risk of esophageal cancer beyond two years has not been demonstrated.
Side effects of Photofrin phototherapy treatment include esophageal strictures and photosensitivity reactions that last for several weeks. The drug’s labeling includes information on precautions that should be taken to avoid exposure of skin and eyes to bright light.
|New Recombinant Antihemophilic Factor|
FDA recently licensed the first clotting factor for patients with Hemophilia A that's produced without using additives derived from human or animal blood. It’s called Advate, and it’s manufactured by Baxter Healthcare Corporation.
Advate is an antihemophilic human Factor VIII product to prevent and control bleeding episodes in people with Hemophilia A, or to prepare them for surgery.
Current clotting factor products, both the ones derived from plasma and the ones made from recombinant DNA, are already considered very safe, because of technological advances in manufacturing in which viruses are inactivated and removed. This minimizes the risk of transmitting infectious agents with Factor VIII products. But avoiding the use of blood-derived additives in the manufacturing process this gives added reassurance against any theoretical risk of infection.
|Update on Cochlear Implants and Meningitis|
In a previous edition of FDA Patient Safety News, we told you about a possible link between cochlear implants and bacterial meningitis. We now have new information on that story. A recent CDC-FDA study found that children with cochlear implants were at greater risk for Streptococcal meningitis than children in the general population. The study reviewed the medical records of over 4,200 children who were under the age of six when they received the implants. Twenty-six of them were reported to have developed meningitis. One finding in the study was that cochlear implants that had electrode positioners were more likely to be associated with meningitis than other models. The models with positioners are no longer on the market.
Among all the U.S. cases that were reported to us, the onset of meningitis ranged from less than 24 hours after the surgery to greater than six years.
FDA and CDC are not recommending that implants with positioners be replaced with other models, because it’s not known whether the risks of the additional surgery might outweigh the risk of having the positioner.
The basic recommendations haven’t changed since the last time we reported on this. First, consider prophylactic antibiotic treatment prior to implanting these devices. Second, promptly diagnose and treat otitis media in patients who already have the implants. And third, for patients who are going to receive the implants, or who already have them, follow vaccination guidelines against the organisms that commonly cause bacterial meningitis. You can find CDC’s vaccination recommendations on our web site.
And CDC’s National Immunization Program has a hotline that provides advice on which vaccines are recommended for cochlear implant patients. The hotline number is 1-800-232-2522.
|Drug Name Confusion: Zyprexa/Zyrtec/Zantac|
Periodically on this program, we point out mix-ups that occur when drug names look or sound alike. This time we're talking about confusions that have occurred between three drugs that all begin with the letter "Z": Zantac, an acid reducer; Zyrtec, an antihistamine; and Zyprexa, an antipsychotic.
First, take Zantac and Zyrtec. FDA has received a number of reports of pediatric medication errors that occurred when Zantac syrup was prescribed, but Zyrtec syrup was dispensed. These two drugs don't have overlapping dosage strengths, but they are both available as a syrup and both are available in amber 1-pint bottles. And the names both look alike and sound alike.
There are also reports of mix-ups between Zyrtec and Zyprexa. The Institute for Safe Medication Practices points out that many of these mix-ups probably occurred when only the first two letters of the drug name were seen by practitioners when reading prescription orders or container labels. Since both drugs are available in 5 mg and 10 mg tablet strengths, this increases the possibility of confusion. ISMP describes a patient who accidentally took Zyprexa instead of Zyrtec, and then suffered a head injury after losing consciousness. In another case, a previously controlled psychotic patient took Zyrtec instead of Zyprexa, and then relapsed. To help alleviate this problem, the manufacturer of Zyprexa has redesigned the product’s label using tall-man lettering to highlight the unique letters in the name.
Here are some ways that you can prevent these kinds of mix-ups. Educate the staff about the medication errors caused by these name confusions. Separate look-alike or sound-alike drugs on the pharmacy shelves. Include the indication for the drug on the prescription. Use name alerts or reminders about the potential for error on computer systems, drug containers and drug storage shelves.
And in situations similar to the Zyrtec and Zyprexa mix-ups, tell patients about the risk of a mix-up and advise them to look at their medication to be sure that it has the right appearance.
- ISMP Medication Safety Alert. October 31, 2001: Action needed to prevent dangerous Zyrtec-Zyprexa mix-ups.
|Caution on Certain Triple Anti-Retroviral Therapy For HIV|
GlaxoSmithKline has notified healthcare providers about a high rate of early virologic non-response in HIV-infected patients receiving a particular three-drug anti-retroviral regimen. The three drugs are Epivir (lamivudine), Ziagen (abacavir) and Viread (tenofovir). This virologic non-response was observed in a company-sponsored clinical trial of HIV-1 infected patients who had not been previously treated with anti-retrovirals.
Based on the clinical study results, GlaxoSmithKline says that abacavir and lamivudine in combination with tenofovir should not be used as a triple antiretroviral therapy when considering a new treatment regimen for either naive or pre-treated patients. Any patient currently controlled on therapy with this combination should be closely monitored and considered for modification of therapy. And any use of this triple combination with other antiretroviral agents should be closely monitored for signs of treatment failure. For more information, go to our website.
|More Dangerous Misconnections|
In a previous story, we described a number of cases where the tubing from a patient's blood pressure monitor was mistakenly connected to the IV port. Some of these cases resulted in the patient dying from an air embolism.
This time we want to draw your attention to a similar case, this time involving the air hose from a sequential compression device that's used with antiembolism stockings. An FDA article in Nursing 2003 describes a report of a confused patient returning from the bathroom. The patient mistakenly attached the air hose from his sequential compression device to his IV tubing, rather than to the antiembolism stocking. Luckily, the compressor was turned off, so air didn't enter the I.V. tubing. If it had, the patient could have sustained an air embolism and died.
Again, the cause of this problem goes back to different devices intended for very different uses having compatible luer connectors that allow them to be attached to one another. The article points out two ways to minimize the risk.
First, if you’re using luer connectors, you should always be alert to the possibility of inadvertent cross-connections. Follow the manufacturer's recommendations and cautions regarding compatibility with other devices, and if you notice potentially dangerous compatibility issues, notify your facility's risk manager and biomedical department.
Second, be aware that confused patients, like the one cited in the article, may be at special risk. It’s important to check on them frequently, and to remind them to call for help if they need to get out of bed.
|Warning on Treating Latent TB with Rifampin and Pyrazinamide|
CDC and the American Thoracic Society are now recommending that patients with latent tuberculosis infection not be treated with the combination of rifampin and pyrazinamide because of the risk of severe liver injury. These revised recommendations were published on August 8, 2003 in the MMWR.
In early 2000, CDC and the American Thoracic Society first recommended a 2-month regimen of rifampin plus pyrazinamide for treatment of latent TB infection. Shortly after this, CDC started receiving reports of liver injury in patients on this therapy, and based on these initial reports, CDC cautioned clinicians about using the two drugs in combination and advised additional monitoring of patients.
In the August MMWR issue, CDC reports on 48 confirmed cases of severe liver injury associated with this combination therapy, including 11 deaths. This led to the latest recommendation that the combination of rifampin plus pyrazinamide generally should not be offered to patients with latent TB infection. The preferred regimen for treating latent TB is isoniazid for 9 months. Alternatives are isoniazid for 6 months or rifampin for 4.
CDC notes that this recommendation does not apply to treating active TB disease, where using rifampin and pyrazinamide in multidrug regimens may be appropriate. And CDC continues to emphasize that treatment of latent TB infection is a key component in the effort to eliminate tuberculosis.
- CDC: Adverse Event Data and Revised American Thoracic Society/CDC Recommendations Against the Use of Rifampin and Pyrazinamide for Treatment of Latent Tuberculosis Infection – United States 2003. MMWR 2003;52:773-739.
- CDC Fact Sheet: Treatment of Latent Tuberculosis Infection (LTBI) Updated August 7, 2003.
- CDC: Dear Colleague Letter - August 7, 2003.
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