The matrix transdermal fentanyl patch provides a continuous delivery of fentanyl over 72 hours, in a manner similar to Duragesic®. During a breakthrough pain episode, a CHADD unit is placed over (adhered to) the matrix transdermal fentanyl patch. The CHADD is a thin patch-like chemical heating device that generates a controlled level of heat for approximately 15-20 minutes. The application of heat delivers increased amounts of fentanyl when applied over the ZR-02-01 matrix transdermal fentanyl patch.