FDA

The Institute for Safe Medication Practices (ISMP) and FDA are warning healthcare professionals that potentially fatal dosing errors continue to occur with the anti-epileptic drug Cerebyx (fosphenytoin), despite clarifications in the drug's labeling that date back to 1999. FDA's MedWatch program has reports of seven cases where young children received an overdose of Cerebyx and died.

Cerebyx doses are expressed as phenytoin equivalents (PE). The problem is that electronic and printed displays in many facilities list the drug as "50 mg PE/mL, 10 mL." That could cause users to believe that a 10 mL vial contains just 50 mg PE rather than 500 mg PE, which could lead to a significant overdose.

FDA has informed the health care community about ongoing safety reviews of several drugs. FDA is doing this as part of its commitment to inform health care professionals and the public about its ongoing drug safety reviews. Because the information is preliminary and there is scientific uncertainty, FDA is not taking regulatory action at this point, and is not advising health care professionals to stop using the drugs. FDA is continuing to evaluate the safety of these products, and will provide updates as more information becomes available.

One communication concerns the possibility of an increased risk of heart attack among HIV patients taking the nucleoside reverse transcriptase inhibitors Ziagen (abacavir) and Videx (didanosine). This information comes from an ongoing international study of over 30,000 HIV patients. This study did not address the heart attack risk with tenofovir or emtricitabine, two other nucleoside reverse transcriptase inhibitors.

FDA is taking action against companies marketing injectable colchicine, which is an unapproved form of the drug. Colchicine is an anti-inflammatory used in the treatment of gout. Colchicine tablets, which are less hazardous, are not affected by FDA's action at this time.

The injectable form of colchicine is especially hazardous because the therapeutic index, which is the margin between an effective dose and a toxic dose, is very narrow. Also, certain side effects that might alert the clinician that the dose is too high do not appear until the patient has already reached toxic levels, which adds to the problem.

Because of its toxicity and the availability of safer therapies, injectable colchicine is rarely used to treat gout anymore. But some practitioners are using this product to treat back pain. FDA believes that the risks of this treatment outweigh the benefits.

Over the past several months, FDA has been alerting healthcare professionals and the public about medical products that may contain contaminated heparin, which has been associated with a number of serious adverse events. Here is an update and recommendations on this continuing issue.

Heparin is an anticoagulant commonly used subcutaneously and intravenously in patients undergoing kidney dialysis, certain types of cardiac surgery and other procedures. It is also used in lock flush solutions to maintain the patency of IV catheters, and as a coating or ingredient in certain medical devices and diagnostic products.

FDA recently approved a new medical adhesive called Artiss to attach skin grafts onto burn patients. Artiss is made by Baxter Healthcare.

Artiss has a lower thrombin concentration than other fibrin sealants, which gives surgeons more time to position the skin graft over a burn before the graft starts to adhere to the skin.

In a multicenter clinical trial, Artiss was compared to surgical staples using two different wound sites on the same patient. The results showed that Artiss was comparable to staples in achieving complete wound closure. The most frequent adverse events, which were seen in both treatment groups, included bleeding and fluid collection in the tissues. Both of these events are common during skin grafting.

Additional Information:

FDA Press Release. FDA Approves New Medical Adhesive to Treat Burn Patients. March 29, 2008.

http://www.fda.gov/bbs/topics/NEWS/2008/NEW01807.html

Keeping glucose levels under control can help people with diabetes feel better and also lower the risk of blindness, kidney disease, and nerve damage. Very high or very low blood sugar can have serious consequences.

Although blood glucose meters are fairly simple to operate, many things can go wrong if the user isn't careful. Here are some tips that can help people with diabetes get accurate results from their glucose meters.

• Be prepared before you do the test. Carefully read all instructions for your meter and test strips. Calibrate the meter or test it to be sure it's calibrated before you use it.

• Be sure that you're using test strips that are specified to work with your meter. Even if an incorrect test strip fits in your meter, it could give you the wrong results. Don't use test strips from a cracked or damaged bottle and don't use test strips that have passed their expiration date.

FDA news

n an April 4, 2008 letter, Cubist Pharmaceuticals advised healthcare professionals not to use the drug Cubicin with ReadyMED elastomeric infusion pumps manufactured by Cardinal Health. Cubicin (daptomycin for injection) is an antibiotic used to treat certain bacteremias and complicated skin infections.

The company's letter says that a potentially significant impurity has been isolated from reconstituted Cubicin that was stored in ReadyMED pumps. The impurity, 2-mercaptobenzothiazole (MBT), is used in rubber manufacturing. MBT has been reported to leach into medical products from rubber stoppers and syringe components in the past.

Schwarz Pharma recalled Neupro (rotigotine) transdermal patches at the end of April 2008. These patches are used to treat early stage Parkinson's disease.

The problem is that rotigotine, the active ingredient, may crystallize in the patch. If that happens, less drug is available to be absorbed through the skin and so the efficacy of the products may vary. The crystallized drug may cause a patch to have snowflake-like patterns. The more snowflakes, the greater the chance that the patch won't work properly.

Because of this, new patients should not be started on Neupro. Patients already using the patch should be slowly titrated off it, and started on an alternative treatment as needed. Patients should not abruptly discontinue treatment with Neupro. The down-titration should proceed according to guidelines in the labeling, using patches that are unaffected or minimally affected by the crystallization.

FDA has informed the health care community about ongoing safety reviews of several drugs. FDA is doing this as part of its commitment to inform health care professionals and the public about its ongoing drug safety reviews. Because this information is preliminary and there is scientific uncertainty, FDA is not taking regulatory action at this point, and is not advising health care professionals to stop using the drugs. FDA is continuing to evaluate the safety of these products, and will issue updates as more information becomes available.

• CellCept (mycophenolate mofetil) and Myfortic (mycophenolic acid)

One of the ongoing safety reviews concerns two drugs used to prevent organ rejection, CellCept (mycophenolate mofetil) and Myfortic (mycophenolic acid). CellCept is approved to prevent heart, liver and kidney transplant rejection. Myfortic is approved to prevent kidney transplant rejection.

FDA news

On January 16, 2008, Medtronic notified healthcare professionals about an increased rate of inflammatory masses in patients receiving intrathecal drugs through the company's Synchromed EL, Synchromed II and IsoMed implantable infusion pump systems. This letter, which also gave patient management and treatment recommendations, was an update to two earlier communications.