Show #60, February 2007
Show #60, February 2007
|Avoiding Accidental Overdoses when Methadone is Prescribed for Pain|
FDA has issued a Public Health Advisory cautioning practitioners about avoiding overdoses when they are prescribing methadone or managing patients taking this drug. Since the 1970s, methadone has been primarily used in treating drug abuse, but now it’s also being used increasingly for the treatment of pain.
FDA issued the Advisory because of reports of life-threatening adverse events and death in patients receiving methadone for pain control. Part of the reason is that physicians prescribing methadone for pain relief may not fully understand the drug’s pharmacology and potential adverse effects. For example, methadone, like other opioids, causes respiratory depression. But in addition, it can also have effects on cardiac conduction, leading to prolonged QT intervals and serious arrhythmias. Methadone also interacts with many other drugs, some of which can slow methadone’s elimination from the body and thus increase the likelihood of overdose and adverse effects related to either respiratory depression or cardiac arrhythmias.
Overdoses can also occur because methadone remains in the body much longer than the drug's analgesic effect lasts. So if a patient takes more methadone to extend the duration of pain relief, he or she may be at serious risk of respiratory depression.
The Advisory lists several recommendations for health care professionals, including closely monitoring patients on this drug, especially when starting treatment or adjusting the dose. This should be done even for patients who are opioid-tolerant.
Because many patients will be taking the methadone at home without medical supervision, much of the responsibility for avoiding overdoses rests with patients and caregivers. Because of this, FDA is working on a Medication Guide for patients, to be distributed when prescriptions for methadone are dispensed.
In the meantime, health care professionals should refer patients to the Patient Package Insert for advice on how to use the drug safely. Here’s what patients should know if they take methadone for pain relief:
• First, don’t take more of the drug than prescribed. If pain isn’t relieved at the prescribed dose, call your doctor.
• Be aware that pain relief may take a few days after you start the drug.
• Get medical attention right away if you experience palpitations, dizziness, lightheadedness or fainting.
• And be sure to tell your doctor about other medications you’re taking because they may interact with the methadone.
|Delayed Onset of Heparin-induced Thrombocytopenia|
FDA is alerting healthcare professionals that the onset of heparin-induced thrombocytopenia (HIT) can be delayed in patients who had previously been treated with heparin sodium injection.
HIT results from an irreversible aggregation of platelets. About half the time, it can lead to development of venous and arterial thromboses, a condition called heparin-induced thrombocytopenia and thrombosis (HITT). If this occurs, serious thrombotic complications can include pulmonary embolism, stroke, MI, skin necrosis, gangrene and even death.
New warnings in the drug label point out that HIT, with or without thrombosis, can occur up to several weeks after heparin therapy is stopped. So patients who present with thrombocytopenia or thrombosis after they discontinue heparin should be evaluated for HIT and HITT. Heparin should not be administered to these patients until their platelet count is checked, because giving heparin to these patients could cause serious or even fatal reactions.
|Reporting Adverse Events for Drugs, Devices, Biologics and Dietary Supplements|
FDA's Medwatch program allows health care professionals and consumers to report to the FDA serious problems with the medical products they prescribe, dispense, or use. These reports, along with follow-up investigations, can help to identify important safety concerns.
Take the example of the antibiotic Zyvox. Within the first six months of Zyvox's marketing, FDA began getting MedWatch reports of myelosupression from clinicians who suspected that the drug might be responsible. After investigating the problem, we worked with the manufacturer to change the Zyvox labeling to warn about the potential for myelosuppression.
Sometimes MedWatch reports highlight errors in prescribing or administering medications. For example, FDA received reports of patient injuries due to name confusion between LANOXIN, a heart medication, and what used to be called LEVOXINE, a thyroid medication. As a result, FDA asked the manufacturer to change the name of Levoxine, and now it's known as LEVOXYL, which is less likely to be confused with LANOXIN.
The MedWatch system can also help detect problems with medical products other than drugs. For example, FDA received two reports of pneumococcal eye infections in patients who'd received corneal transplants. An FDA inspection identified numerous manufacturing problems, which led the company to recall the implants.
Of course, MedWatch reports by themselves can not usually establish a causal relationship between an adverse event and a medical product - it may take a formal epidemiologic study to do that. Still, MedWatch reports are vital in making sure that medical products are safe, because they provide a rapid signal to FDA that problems may be occurring.
It is important to keep the MedWatch system working, and we can not do that without your help. Here are the kinds of reports we need from you:
• First of all, we are asking that you report any serious adverse event that might be associated with a drug, biologic, medical device, or dietary supplement. By "serious" we mean fatalities, hospitalizations, and medically significant events. We're especially interested in serious adverse events that aren't listed in the product labeling.
• Secondly, report therapeutic failures - cases where the drug or device failed to work as it should. For example, let us know if a patient has to switch from one brand of a drug to another because the original one was ineffective.
• Third, tell us about cases of use errors with medications or devices, including situations where the error may have been due to poor communication, or to ambiguities in product names, directions for use, or packaging.
• And finally, we would like to know about product quality issues, such as suspected counterfeit products, defective components, potential contamination, device malfunctions and poor packaging.
We encourage you to report these problems to MedWatch even if you are not sure that the product was the cause. It is easy to report by internet, phone, fax, or mail.
|Cardiac Events with Gleevec|
Novartis is notifying healthcare professionals about new precautions for Gleevec (imatinib mesylate). Gleevec is used to treat certain patients with chronic myeloid leukemia and gastrointestinal stromal tumors.
A recent article published in Nature Medicine reported on ten patients taking Gleevec who developed severe congestive heart failure and left ventricular dysfunction. Before starting treatment, most of these patients had
pre-existing conditions such as hypertension, diabetes and
coronary artery disease. The article also reported on preclinical studies showing that mice treated with the drug developed left ventricular contractile dysfunction.
Novartis has now added a precaution to the drug labeling about severe congestive heart failure and left ventricular dysfunction. The company also says that patients with cardiac disease or risk factors for cardiac failure should be monitored carefully, and any patient with signs or symptoms consistent with cardiac failure should be evaluated and treated.
|Avoiding Burns from Electrodes and Cables during MRI Exams|
A recent FDA article in Nursing2006 describes second and third degree burns in patients undergoing MRI exams while they were wearing ECG electrodes and cables. Many of these burns were discovered only after the exam was over and some were severe enough to require plastic surgery.
The problem is that the radiofrequency fields created during an MRI exam can heat ECG cables and electrodes, seriously burning the underlying skin. This hazard is likely to increase as the number of MRI exams goes up, and as more patients need ECG monitoring during their MRI procedures.
The article recommends a number of ways to reduce the risk of these kinds of burns. Here are some of them:
• Remove any electrodes and cables that are no longer being actively used for monitoring. Search the patient for any electrodes and cables that may have been inadvertently left behind in clothing or sheets, or on the patient.
• If the patient needs ECG monitoring during the MRI procedure, check beforehand with the MRI staff to be sure that the cables and electrodes have been cleared for use in the MRI environment. If still in doubt, check with the manufacturer of these devices.
• Be sure that there is complete contact between the electrode surface and the patient's skin. If contact is poor - for example, if excess hair hasn't been removed or there's an air gap between the electrode and the skin - a serious burn can occur even if you are using electrodes and cables that are approved for MRI. Inadequate contact can also occur if the gel layer on the electrode has dried out, so avoid using electrodes that are past their expiration date and inspect each electrode before using it.
• Avoid looping and crossing the cables, because this can create excessive heat from resistance in the cable, which can burn the patient. Keep cables off the patient's skin by placing padding, such as a blanket, between the cable and the skin.
• After completing the MRI study, examine the patient for possible burns or reddening of the skin under the electrodes. This is especially important for patients who can't express themselves, or those who have impaired sensation. If the patient has a burn, administer appropriate treatment.
|Possible Dosing Errors with the OptiClik Insulin Injection Device|
A recent report from the Institute for Safe Medication Practices points out a potential problem in using the OptiClik injection pen, which administers Lantus or Apidra insulin. ISMP says that practitioners or patients could administer the wrong dose if they are left handed.
In operating the device, the user dials the insulin dose by turning a knob at the end of the pen, and the selected dose appears in a small window on the pen. ISMP notes that users tend naturally to grasp the pen with the non-dominant hand and turn the knob with the dominant hand.
For right-handed people, this will orient the pen in the proper direction-that is, with the knob to the right and the needle to the left. But if a “lefty” grabs the pen with the right hand and turns the knob with the left, this will turn the pen around, and the window showing the dose will be upside down.
So, left-handed patients and practitioners using the OptiClik device should be careful that they have the pen properly oriented when they dial the dose-needle pointing left, knob on the right. This can be confirmed by making sure that the “OptiClik” printing on the pen is right-side-up.
- ISMP Medication Safety Alert! Pharmaceutical Industry, Medical Device Company - Part of the Solution. November 16, 2006.
- Lantus Website – “Opticlik” injection video. Updated June 2006.
|Dangerous Use of Saline Flush Syringes|
The Institute for Safe Medication Practices recently alerted health professionals about the danger of using pre-filled saline flush syringes to reconstitute medications. In this process the practitioner first discards any unneeded saline from the syringe, then adds the remaining saline in the syringe to a vial of medication. The practitioner mixes the contents of the vial and draws it back into the syringe, ready to administer.
This could be an accident waiting to happen. A syringe labeled “0.9% saline flush” now contains an additional drug, perhaps even a high-alert medication, with no label. If the syringe leaves the preparer's hands before it is used, another practitioner could pick it up and use it on a patient as a saline flush, possibly with lethal consequences.
ISMP says that practitioners should understand how risky this procedure is. It recommends that medications should be dispensed in ready-to-use form whenever possible. If it is necessary to reconstitute or dilute the medication on the unit, staff should be given blank syringe labels, and these should be applied to the final product immediately.
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