Avoid heating up a pain patch

Before leaving the hospital, a woman with bone cancer was given a prescription for a powerful pain medicine, called Duragesic. This is a medicine "patch" or "transdermal system" that adheres to the skin and slowly releases the powerful opioid fentanyl. During her first 2 weeks at home, she was doing well. The medicine was helping to relieve her back pain. But then her family noticed that she seemed confused and was losing her balance. She was also nauseated and had vomited.

The problem was uncovered while reviewing the woman's symptoms with her doctor. The woman had been placing the fentanyl patch on her back, near the pain. At the same time, she often sat in her favorite recliner with a heated seat. The heat from the chair was directly over the medicine patch. The heat caused the powerful pain medicine to be released from the patch too quickly. The woman had been receiving an overdose of fentanyl every time she sat in her heated recliner. The overdose explained her confusion, loss of balance, and nausea and vomiting.

Exposing fentanyl patches and other medicine patches to heat could increase the amount of drug absorbed from the patch into the body. So, it is important to avoid heating pads, electric blankets, heat or tanning lamps, sunbathing, hot baths, saunas, hot tubs, heat wraps, heated water beds, or heated seats. Even vehicles with heated seats can affect how much medicine the body absorbs with a patch during a long car ride.

Avoid tight coverings over the patch and strenuous exercise too. These can also heat the body. Medicine patches should not be applied to irritated skin on the chest, back, flank, or upper arm. If you are receiving radiation treatments, it is also important not to place a medicine patch on the skin over the area that is receiving the radiation.

Also, medicine patches do not need to be placed directly on or near the area that hurts. The pain medicine from the patch is absorbed and used throughout the whole body. So, you do not need to place the patch near the pain.

Speaking of medicine patches and fentanyl, this past week a drug company known as The Medicines Company announced a new form of transdermal fentanyl called Ionsys. This is designed for short term use in hospitalized patients who need an opioid after major surgery. I shouldn't really be referring to this as a pain "patch." The new product, which will be available later this year, is actually a credit card size device that also sticks to the skin but it has internal electrical circuitry that allows the release of the drug to be controlled by the patient.

To use Ionsys the patient simply pushes a button twice in quick succession to set off an imperceptible electrical charge that drives fentanyl through the skin on demand. Up to 6 doses can be released per hour if the patient feels they need it. The device stops working after 24 hours but a new device can be placed on the patient for two more days if needed. Patients will need close monitoring to assure they aren't giving themselves too much.

FDA has required the manufacturer to develop risk prevention strategies (called Risk Evaluation and Mitigation Strategies or REMS) that the hospital must use to assure proper use of the drug, including limiting use to patients in the hospital only and reducing the risk of respiratory depression resulting from accidental exposure to people for whom it is not prescribed. The REMS includes a requirement for the hospital to use a registry in order to obtain supplies.

Ionsys was first approved by FDA in 2006 but was never marketed in the US. It had been marketed in the European Union but was withdrawn due to corrosion seen on the internal circuit boards that theoretically might have caused self-initiation of the unit and release of fentaNYL without pushing the button. The company told us this week that improvements have been made to address this issue. The company agreed to monitor Ionsys and regularly report any problems to FDA.

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