#transdermal fentanyl

This medication is a Schedule II drug

Brand Name: Duragesic

Generic Available

Common Dosage Forms:

Transdermal Systems (*for use only in opioid tolerant patients): 12 mcg/hour, 25 mg mcg/hour, 37.5 mcg/hour, 50 mcg/hour*, 62.5 mcg/hour, 75 mcg/hour*, 87.5 mcg/hour, 100 mcg/hour

FDA Indications/Dosages:

Management of chronic pain in patients requiring opioid analgesia: One patch applied topically and replaced every 73 hours. Doses must be individualized based upon the status of each patient and should be assessed at regular intervals after fentanyl application. In selecting an initial fentanyl dose, attention should be given to (1) the daily dose, potency, and characteristics of the opioid the patient has been taking previously (e.g., whether it is a pure agonist or mixed agonist-antagonist), (2) the reliability of the relative potency estimates used to calculate the fentanyl dose needed (potency estimates may vary with the route of administration), (3) the degree of opioid tolerance, if any, and (4) the general condition and medical status of the patient.

Conversion from oral or parenteral opioids to fentanyl use the following methodology: (1) Calculate the previous 24-hour analgesic requirement, (2) convert this amount to the equianalgesic oral morphine dose, (3) use the table supplied with the package insert to calculate the corresponding fentanyl dose. Initiate treatment using the recommended dose and titrate patients upwards (no more frequently than every 3 days after the initial dose or every 6 days thereafter) until analgesic efficacy is attained. For delivery rates in excess of 100 mcg/hour, multiple systems may be needed.

Patients should use short-acting analgesics for the first 24 hours as needed until analgesic efficacy is attained. Thereafter, some patients still may require periodic supplement doses of other short-acting analgesics for “breakthrough” pain.

Pharmacology/Pharmacokinetics: Fentanyl is an opioid analgesic, therefore, analgesia is produced centrally via action on the central opioid u-receptor. Two different forms of fentanyl patches are available commercially. One releases fentanyl from the reservoir at a nearly constant amount per unit unit time. The concentration gradient existing between the saturated solution of drug in the reservoir and lower  and the lower concentration in the skin drives drug release. The second is a matrix-style patch. The concentra-concentration in the gradient between the drug in the matrix and the lower concentration in the skin drives drug release. Following initial application, the skin under the system absorbs fentanyl, and depot of fentanyl concentrates in the upper skin layers. Serum fentanyl concentrations increase gradually following application, generally leveling off between 12 and 24 hours and remaining relatively constant, with some fluctuation, for the remainder of the 72 hour application period. Peak serum levels of fentanyl generally occur between 12 and 24 hours after a single application. Fentanyl is metabolized primarily in the liver.

Drug Interactions: Additive CNS depression occurs when used with phenothiazines, general anesthetics, sedatives, hypnotics, alcohol, skeletal muscle relaxants, and agonist/antagonist analgesics. CYP3A4 inhibitors (macrolide, antibiotics, azole-antifungals, protease inhibitors) may increase plasma levels. Discontinuations of CYP3A4 inducers (rifampin, carbamazepine, phenytoin) while on fentanyl will also increase plasma levels.

Contraindications/Precautions: Fentanyl is contraindicated in patients with known hypersensitivity to fentanyl or adhesives. OPIOIDS CAN BE ADDICTIVE, ABUSED, AND MISUSED WHICH CAN LEAD TO OVERDOSE AND DEATH. SERIOUS, LIFE-THREATENING RESPIRATORY DEPRESSION MAY OCCUR. Patients who have experienced adverse events should be monitored for at least 12 hours after patch removal since serum fentanyl concentrations decline gradually and reach an approximate 50% reduction in serum concentrations 17 hours after system removal. ACCIDENTAL EXPOSURE CAN BE FATAL, ESPECIALLY IN CHILDREN. Because hyperventilation may occur at any time during the use, use with caution in patients who have preexisting medical conditions predisposing them to hypoventilation and to patients with head injuries, increased intracranial pressure, brain tumors, bradyarrhythmias, and in patients with impaired renal or hepatic function. HEAT FROM EXTERNAL SOURCES CAN INCREASE SYSTEMIC ABSORPTION. When patients are receiving other CNS depressants (including benzodiazepines) their dose should be reduced by at least 50%. CONCOMITANT USE WITH CYP3A4 INHIBITORS, BENZODIAZEPINES, ALCOHOL, OR OTHER CNS DEPRESSANTS CAN RESULT IN RESPIRATORY DEPRESSION, COMA, AND DEATH. Pregnancy Category C.

Adverse Effects: Hypoventilation, hypotension, hypertension, abdominal pain, headache, nausea, vomiting, constipation, dry mouth, anorexia, diarrhea, dyspepsia, somnolence, confusion, asthenia, dizziness, nervousness, hallucinations, anxiety, depression, euphoria, dyspnea, apnea, sweating, pruritus, and urinary retention.

Patient Consultation:

Patches should be applied to non-irritated and non-irradiated skin on a flat surface of the upper torso. Do not apply to extremities below the knee or elbow. Hair at the application site should be clipped (not shaved) prior to application. If the site of patch application site must be cleansed prior to application of the system, do so with clear water. Do not use soaps, oils, lotions, alcohol, or any other agents that might irritate the skin or alter its characteristics. Allow the skin to dry completely prior to system application.

Patches should be applied immediately upon removal from the sealed package. The transdermal system should be pressed firmly in place with the palm of the hand for 10-20 seconds.

Each patch may be worn continuously for 72 hours. If analgesia for more than 72 hours is required, a new system should be applied to a different skin site after removal of the previous transdermal system.

Used and unused systems should be folded so that the adhesive side of the system adheres to itself, then flushed down the toilet immediately upon removal. Keep out of reach of children and pets, even after removal.

Do not cut or puncture systems.