Fimea issues a warning: Wearing an opioid patch in the sauna may cause life-threatening poisoning

The Finnish Medicines Agency Fimea reminds that subjecting transdermal opioid patches to external heat may increase the concentration of the transdermally delivered substance in the blood, which can lead to fatal poisoning. 

Transdermal opioid patches should not be subjected to, for example, sauna, heat pads or warm baths as this may cause the substance in the patch to be absorbed into your body too fast. You should always remove the transdermal patch before sauna. 

Fimea has been made aware of five cases in Finland over the past ten years where wearing a transdermal fentanyl patch in the sauna has lead to a fatal fentanyl poisoning. 

Check the package leaflet for instructions

The application site of transdermal opioid patches (e.g. fentanyl or buprenorphine patches) should not be subjected to external sources of heat, such as sauna, heat pads or blankets, a heated waterbed, sunbathing, hot-water bottles, long hot baths or hot tubs. High fever may also increase drug absorption, which is why the proper treatment of high fever is important. 

Even if your transdermal patch does not contain opioids, we recommend that you check the package leaflet for any instructions regarding external sources of heat, such as sauna. Package leaflets are included in every medicine package. You can also find package leaflets by using FimeaWeb medicine search. 

If you have any questions about your medication, please contact your treating physician or treatment unit. You can also ask a pharmacy for advice.