Show #10, November 2002
Show #10, November 2002
|New Drug for Chronic Hepatitis B|
In a recent Talk Paper, FDA announced the approval of a new drug called Hepsera to treat chronic hepatitis B. Its generic name is adefovir dipivoxil, and it's made by Gilead Sciences, Incorporated.
Chronic hepatitis B is often a lifelong infection that can cause cirrhosis, liver cancer, liver failure and death. According to CDC, over one million Americans are chronically infected with hepatitis B. Hepsera slows the progression of the disease by disrupting the DNA in the hepatitis B virus, thereby interfering with the ability of the virus to replicate itself.
This drug is intended for patients who have histologically active disease, or who show evidence of active viral replication, provided that they also have either elevations in serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST). Hepsera has been shown effective in treating patients with chronic hepatitis B who are resistant to another approved antiviral drug, lamivudine.
FDA based its approval of Hepsera on the results of two randomized, double-blind, placebo-controlled studies. After 48 weeks, a significantly greater percentage of patients in the treatment group showed improvement in liver inflammation and fibrosis, compared with those receiving the placebo.
One of the major adverse events associated with the use of Hepsera is kidney toxicity. Another is acute exacerbation of hepatitis B. This occurred in 25% of patients in the clinical trial when they stopped taking the drug. The same thing has occurred in patients who discontinued other approved hepatitis B products. And so it's important that patients who discontinue Hepsera be periodically monitored for hepatic function.
Kidney toxicity was also reported in patients who have, or may be at risk for, kidney dysfunction. In addition, there's a theoretical concern that if a chronic hepatitis B patient also has unrecognized or untreated HIV infection, treatment with Hepsera could cause HIV resistance.
|New Preservative-free Flu Vaccine Approved|
The FDA recently approved an influenza vaccine that does not contain thimerosal as a preservative and can be used for young children, those six months or older. It's called Fluzone, and it's manufactured by Aventis Pasteur, Incorporated.
Previously, FDA approved another flu vaccine that does not contain thimerosal as a preservative, and it's indicated for persons four years and older. It's called Fluvarin, manufactured by Evans Vaccines Limited. Both of these vaccines are available in single-dose units that contain only a trace amount of thimerosal, and they continue to be available in multi-dose vials that do contain thimerosal as a preservative.
Thimerosal contains mercury. It's been commonly used as a preservative in vaccines since the 1930's. Although the small amounts of mercury that patients would receive from vaccines have not been shown to be harmful, reducing mercury exposure from all sources, including food, medical products, and the general environment, is an important public health goal. And so FDA has been working with manufacturers to reduce or eliminate the use of thimerosal as a preservative in drugs and vaccines. With the approval of Fluzone, practitioners now have an additional way to help minimize mercury exposure in young children.
- Product Approval Information - Licensing Action.
- Thimerosal in Vaccines.
- Thimerosal in Vaccines- Frequently Asked Questions.
|New Drug for Women with Constipation-Predominant IBS|
In a recent Talk Paper, FDA announced the approval of a new drug for short-term treatment of women with irritable bowel syndrome whose primary symptom is constipation. The drug, called Zelnorm, is manufactured by Novartis Pharmaceuticals Corporation. Its generic name is tegaserod maleate.
Zelnorm works by normalizing impaired motility in the gut. It stimulates peristaltic reflex and intestinal secretion, as well as inhibiting visceral sensitivity. Thus it can reduce abdominal pain, bloating and constipation.
FDA based its decision to approve Zelnorm on the results of three randomized, double-blind, placebo-controlled studies, each lasting twelve weeks. During the studies, patients were asked each week to rate their overall well-being, abdominal symptoms, and bowel habits.
At the end of the studies, the proportion of patients responding to Zelnorm was greater than the proportion responding to the placebo. The differences in response rates between Zelnorm vs. placebo were greater at four weeks than at 12 weeks. That suggests that the efficacy of the drug may decrease over time. The efficacy of Zelnorm has not been studied beyond twelve weeks. And keep in mind that the safety and effectiveness of Zelnorm has not been studied in men.
The adverse event most often reported with Zelnorm was diarrhea, which occurred in 9 percent of patients. Typically, this resolved without the patient having to withdraw from the study.
|Drug Name Confusion: Serzone and Seroquel|
Drug names, particularly proprietary names, can look or sound alike. When one drug is mistaken for another, serious patient injuries can occur. Take the case of Serzone and Seroquel. Serzone, manufactured by Bristol-Myers Squibb, is approved to treat depression. Seroquel, made by Astra-Zeneca, is indicated for treating schizophrenia.
FDA has received several dozen reports of medication error where these two drugs were mixed up. Because of the similarity in the sound and look of the two names, pharmacists incorrectly interpreted written and verbal prescriptions. They also labeled and filled them incorrectly- Serzone for Seroquel, and vice versa. Patients who received the wrong drug suffered a variety of adverse events. Several required emergency room visits, and a few were hospitalized.
Besides the similar sounding names, other factors contributed to the confusion. For example, both Serzone and Seroquel are taken orally, both are prescribed BID, and there’s some overlap in the available strengths of the two drugs. And because both names start with the same three letters, they are stored next to each other on pharmacy shelves, further increasing the risk of errors. Even the distinctive appearance of the Serzone and Seroquel tablets did not prevent the errors. In several incidents, the pharmacists placed Seroquel in a pharmacy bottle labeled Serzone, or vice versa, because they selected the wrong product from the pharmacy shelf.
Here are ways to help prevent these kinds of name confusion errors:
* Educate the staff about the medication errors caused by name confusion.
* Verify all orders between pharmacists and prescribers by spelling both the proprietary name and the generic name.
* Counsel patients in detail about their prescribed drug.
* When drug names can be easily confused, consider using computerized name alerts as well as reminders on drug containers and drug storage shelves.
* And separate look-alike or sound-alike drugs on the shelves
|Update on Cochlear Implants and Meningitis|
In a previous broadcast, we reported on a possible association between cochlear implants and bacterial meningitis. Since then, FDA has received reports of additional cases of meningitis in cochlear implant patients.
It's still not certain whether the implants themselves are raising the risk of meningitis, by serving as a focal point for infection, or whether some predisposing factor might be responsible. For example, some deaf patients may have congenital abnormalities of the inner ear which make them more susceptible to meningitis. Or, patients might have had otitis media prior to the surgery.
Our notification recommended that physicians consider prophylactic antibiotic treatment prior to implanting these devices and that they promptly diagnose and treat otitis media in patients who already have the implants.
It also suggested that cochlear implant recipients might benefit from vaccinations against the organisms that commonly cause bacterial meningitis.
Since our last story, the FDA, CDC and state health departments have begun a comprehensive investigation of the apparent association between meningitis and cochlear implantation. This study focuses on children under 6 who have the implants.
The CDC has a special phone number to report cases of meningitis in implant patients - so they can be included in this study. CDC also has a telephone hotline to advise persons with cochlear implants on appropriate immunizations. You can also find both phone numbers on our website.
- FDA Public Health Web Notification: Cochlear Implant Recipients may be at Greater Risk for Meningitis.
|Possible Risks Associated With IGIV|
FDA has received reports of serious thrombotic events occurring in patients following administration of Immune Globulin Intravenous, or IGIV. At this point, we don't know if these thrombotic events were caused by IGIV administration. And we don't have sufficient evidence to tie these events to a specific characteristic of IGIV products, such as excipients, concentration, or traces of procoagulants.
Although the cause of this problem is still unclear, you should be aware that rapid infusion rates and high doses of IGIV might be potential risk factors for this complication in patients who are already at risk for thrombotic events.
FDA will continue to investigate these reports, and we'll keep you informed in future broadcasts.
|LASIK Eye Surgery Website|
LASIK eye surgery is a popular elective procedure intended to reduce a person's dependency on glasses or contact lenses, and some of your patients may be asking you about the procedure. FDA has a consumer website on LASIK surgery, and it's recently been updated with additional information and helpful tips.
LASIK surgery corrects refractive errors in the eye by reshaping the cornea. Using an excimer laser, precise amounts of corneal tissue are removed, and this changes its focusing power. Here's how the procedure is done. A microkeratome is used to cut a flap in the cornea, with a hinge left at one end of this flap. The flap is folded back revealing the stroma - the middlesection of the cornea. Pulses from a computer-controlled laser vaporize a portion of the stroma and the flap is replaced.
The website provides helpful tips for choosing the right doctor. It also gives a list of factors that will help potential patients decide if they're good candidates for the procedure. The website points out that patients with refractive instability may face additional risks. These patients include those in their early 20's or younger, those whose hormones are fluctuating due to disease such as diabetes, those who are pregnant or breast feeding, and those who are taking medications that may cause fluctuation in vision.
Patients who should avoid LASIK surgery entirely include those with a history of herpes in the eye area, glaucoma, certain eye diseases, or eye injuries.
The website encourages patients to carefully weigh all of the risks and benefits of the surgery. It points out that even with surgery, patients should be aware that they may not achieve 20/20 vision, and may still require glasses or contact lenses. The surgery could cause patients to lose some vision that's not correctable with glasses, contact lenses or additional surgery.
|AED’s are Becoming More Visible in Public Places|
Your patients may be noticing devices located in health clubs, hotels and airports called Automated External Defibrillators or AED's. They may be wondering whether they should try to use them in an emergency, and if so, how.
These devices are designed to be as easy to use as possible. For example, they only advise the operator that a shock is needed when a patient is in ventricular fibrillation or fast ventricular tachycardia.
But still, they should only be used by people who've received some training. The American Heart Association recommends that people who live or work in a place that has one of these devices, participate in a Heartsaver AED course. The course explains the Chain of Survival and how important the AED is in that chain.
In the course, your patients will learn that the first step in an emergency is to call 911 and send someone to get the AED. Then they should administer CPR until the AED arrives and continue using the AED and CPR until emergency personnel get there. They'll also be cautioned that the AED should not be used on a child younger than 8 years old.
The AHA offers these courses through local Community Training Centers. If your patients are interested in learning more about public access defibrillators, refer them to our website, where there's a link to the AHA's website.
By the way, if you're interested in having one of these defibrillators installed in a public facility near you, you may be able to arrange that through the AHA. A physician must issue a prescription for a facility to purchase the device. You can get more information on this from the AHA's web site.
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