Fentanyl is a very strong prescription pain medication used to treat severe chronic pain that has not responded to other pain medication. It is available as a patch that is applied to the skin. There are several strengths of fentanyl patch, and each strength is regulated to provide a certain amount of medication over an hour for a total of 72 hours. Once a fentanyl patch is in contact with the skin, it releases active medication. The patch is discarded after 72 hours, and a new patch is reapplied if needed.
Structure and Design
The fentanyl transdermal patch is a clear rectangular patch with three layers. The outermost layer is a thin protective film that is removed to expose an adhesive side that sticks to the body. The middle layer contains the active drug, which is adhered into the layer. The outermost layer is the backing that is exposed to the surface after the patch has been attached. The outer and inner layers serve as protective barriers to the active drug in the middle. They also protect patients and caregivers from accidental exposure to the drug. The inner layer is composed of a matrix that allows for a constant movement of drug from the layer to the skin into the blood.
Strength and Dosage
Fentanyl is manufactured in five different strengths. The nomenclature of the strengths are based on the release rate of the patch. The strength is depicted as mcg (micrograms), and this is released over hours, thus mcg/hr. The readily available doses are 12 mcg/hr, 25 mcg/hr, 50 mcg/hr, 75 mcg/hr and 100 mcg/hr. If a patient has been prescribed 12 mcg/hr based on existing medical issues, and the patch is cut, the medication will be released at a much higher rate since the control matrix on the drug layer is broken. This can cause immediate respiratory difficulties.
Administration
Once the patch is applied to the skin, the inner layer is in contact with the skin and releases medication slowly into the body at a predetermined rate. If the patch is cut, the matrix of the inner drug layer is broken, and if applied to the skin, fentanyl will be released into the body erratically, causing an overdose. Also, when the patch is cut, the active drug can be exposed to caregivers and other family members who come in contact with the patch, and this can be fatal.
Effects
Fentanyl overdose can occur from using a patch that has been cut, damaged or tampered with in any way. Discard a patch with a broken covering pouch. Overdose will present predominately as respiratory depression, which is life-threatening. Respiratory depression is characterized by a reduction in breathing as well as long deep breaths accompanied by periods of no breathing. When this happens, the body does not get enough oxygen, causing the patient to go into deep sedation, and possible death.
Grapefruit Juice and Heat
Grapefruit juice and heat have a similar effect on the fentanyl patch. Grapefruit juice affects the body's mechanism of eliminating fentanyl, causing it to accumulate as an overdose. If grapefruit juice cannot be avoided while on fentanyl, then a dose reduction is necessary. Several prescription medications also cause fentanyl accumulation, so inform the doctor of other medications to prevent fatal drug interactions. Heat causes fentanyl to be released at an accelerated rate. Avoid hot environments such as a hot bath, tanning, fever, heating blankets, heating pads and any other source of heat around the patch to avoid overdose.
