Duragesic

Duragesic is a prescription drug used for the treatment of chronic pain.

Fentanyl, the active ingredient in Duragesic, belongs to a family of drugs called opioids. Other members of this family include morphine and codeine.

Duragesic is marketed by Ortho-McNeil, a Johnson and Johnson company, and was approved by the FDA in November 2001.

Uses
Duragesic is specifically indicated for the management of persistent chronic pain that:


 * Requires continuous opioid treatment for an extended period of time, and
 * Cannot be managed through non-steroidal analgesics and other opioids

How Duragesic is Taken
Duragesic is a patch applied to a flat part of the body such as the chest, back, flank, or upper arm.

The recommended initial dose can be conservatively based upon an equivalent daily oral morphine dose.

Each Duragesic may be worn continuously for 72 hours. The next patch should be applied to a different skin site after removal of the previous patch.

How Duragesic Works
As mentioned earlier, fentanyl is an opioid.

Fentanyl interacts predominately with the opioid mu-receptor to exert its pain-killing effects. Though mu-receptors are found in many tissues of the body, fentanyl effects are generated through interaction with the receptors in the brain and spinal cord (central nervous system).

How the Body Affects Duragesic
Following application of the Duragesic patch, the skin underneath it absorbs fentanyl and its concentrates into the upper skin layers. Fentanyl then becomes available to the systemic circulation.

Peak circulating levels of fentanyl occur between 24-72 hours after initial application. After several 72-hour applications of the patch, a steady state level is reached.

After stopping Duragesic use, fentanyl levels decline gradually through metabolism. Fentanyl is metabolized primarily via the liver enzyme CYP3A4. Approximately 75% of the dose is excreted in urine, mostly as inactive metabolites. Approximately 9% of the dose is excreted in the feces, primarily as metabolites.

Side Effects
The most common serious side effects of Duragesic use are:


 * Hypoventilation (reduced breathing)
 * Hypotension (low blood pressure)
 * Hypertension (high blood pressure)

Risks and Precautions

 * Duragesic contains fentanyl, which is a Schedule II opioid. Schedule II opioids, such as hydromorphone, methadone, morphine, oxycodone, and oxymorphone, have a high potential for addiction and abuse. There is also a risk of fatal overdose due to respiratory depression.


 * Duragesic may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating machinery).

Drug Interactions

 * Fentanyl is metabolized mainly via the liver enzyme CYP3A4. The concurrent use of fentanyl with CYP3A4 inhibitors like ritonavir, ketoconazole, itraconazole, troleandomycin, clarithromycin, nelfinavir, and nefazodone may result in an increase in circulating levels of fentanyl.  If these medications are also being used, a decrease in dose may be necessary.


 * Concurrent use of Duragesic with other central nervous system depressants with other drugs that depress the central nervous system like opioids, sedatives, hypnotics, tranquilizers, general anesthetics, phenothiazines, skeletal muscle relaxants, and alcohol, may cause decreased breathing, low blood pressure, and profound sedation. Very high doses can result in coma or death. In these circumstances, the dose of one or both drugs need to be significantly reduced.


 * Duragesic is not recommended for use in patients who have received MAO inhibitors (MAOI's) within 14 days.

Effectiveness
In one study of Duragesic's effectiveness in treating chronic pain, 63.4% of patients improved, while 28.9% of patients worsened by the end of the study.