DURAGESIC-12
Clinical safety rating
cautionComprehensive clinical and safety monograph for DURAGESIC-12 (DURAGESIC-12).
Fentanyl is a potent synthetic opioid agonist that primarily binds to mu-opioid receptors in the central nervous system, leading to analgesic effects by increasing potassium conductance and decreasing calcium influx, thereby inhibiting ascending pain pathways and altering pain perception.
| Metabolism | Fentanyl is primarily metabolized in the liver via CYP3A4-mediated N-dealkylation to norfentanyl, an inactive metabolite. Approximately 75% of the dose is excreted in urine, mainly as metabolites, with less than 10% as unchanged drug. |
| Excretion | Renal: approximately 75% as metabolites (primarily norfentanyl and other inactive metabolites) and <10% as unchanged fentanyl; fecal: approximately 9%; biliary: minor. |
| Half-life | Terminal elimination half-life is approximately 20–27 hours (range 13–44 hours) after transdermal patch removal; prolonged in elderly, hepatic impairment, and with continuous use due to drug accumulation in skin and adipose tissue. |
| Protein binding | Approximately 80–85% bound to plasma proteins, primarily albumin and α1-acid glycoprotein. |
| Volume of Distribution | Approximately 6 L/kg (range 3–8 L/kg) after intravenous administration; high Vd indicates extensive tissue distribution and accumulation in fat and muscle. |
| Bioavailability | Transdermal: approximately 92% relative to intravenous; absolute bioavailability is about 30–40% (due to first-pass metabolism, but transdermal bypasses hepatic first-pass, hence high relative bioavailability). |
| Onset of Action | Transdermal: 12–24 hours (serum levels plateau at 12–24 hours, but initial analgesia may take up to 24–48 hours to achieve steady state; onset is delayed compared to IV/IM routes). |
| Duration of Action | Transdermal: approximately 72 hours per patch; analgesic effects persist for 12–24 hours after patch removal due to continued absorption from skin depot. |
| Molecular Weight | 336.47 |
Transdermal patch, initially 12 mcg/h applied every 72 hours in opioid-naive patients; titrate based on response and tolerance.
| Dosage form | FILM, EXTENDED RELEASE |
| Renal impairment | GFR 30-89 mL/min: start at 50% of usual initial dose; GFR <30 mL/min: avoid use or start at 50% of usual dose with cautious titration. Not recommended in dialysis patients. |
| Liver impairment | Child-Pugh class A: start at 50% of usual initial dose; Child-Pugh class B: start at 25% of usual dose; Child-Pugh class C: avoid use due to extreme risk of toxicity. |
| Pediatric use | For pediatric patients aged 2-16 years currently receiving and tolerant to opioids (equivalent to at least 60 mg oral morphine/day): initial fentanyl dose (mcg/h) based on previous 24-hour opioid requirement using standard conversion; apply patch every 72 hours. For opioid-naive pediatric patients: not recommended. |
| Geriatric use | Initiate at 50% of usual adult starting dose (e.g., 12 mcg/h every 72 hours) due to increased sensitivity and reduced clearance; titrate cautiously with longer intervals between dose adjustments. |
| 1st trimester | Avoid. Fentanyl crosses placenta; risk of neural tube defects and other congenital anomalies in first trimester. Limited human data, but animal studies show teratogenicity at high doses. |
| 2nd trimester | Use only if benefits outweigh risks. Prolonged use may lead to fetal opioid dependence and neonatal abstinence syndrome. Consider risk of preterm labor. |
| 3rd trimester | Avoid prolonged use. Risk of neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at birth. Use lowest effective dose for shortest duration if necessary. |
Clinical note
Comprehensive clinical and safety monograph for DURAGESIC-12 (DURAGESIC-12).
| Placental transfer | Fentanyl readily crosses the placenta; detectable in fetal plasma within minutes of maternal administration. Fetal-to-maternal ratio approximately 0.4-1.0. |
| Breastfeeding | Fentanyl is excreted into breast milk in low concentrations. With maternal use, infant exposure is minimal but may cause sedation or respiratory depression. Monitor infant for drowsiness, poor feeding, and respiratory rate. Avoid use in breastfeeding women with infants under 6 months of age or those with underlying respiratory issues. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy category C. First trimester: Limited data; theoretical risk of neural tube defects if folate deficiency exacerbated. Second and third trimesters: Risk of neonatal withdrawal syndrome, respiratory depression, and decreased fetal growth; avoid prolonged use near term. |
| Fetal Monitoring | Monitor maternal vital signs and pain scores; fetal heart rate monitoring if near term or prolonged use; assess neonatal for signs of withdrawal and respiratory depression postpartum. |
| Fertility Effects | May impair female fertility via disruption of gonadotropin-releasing hormone pulsatility leading to anovulation; male fertility impact unknown but opioid use can reduce libido and erectile function. |
■ FDA Black Box Warning
WARNING: LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL EXPOSURE; ABUSE POTENTIAL; RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; NEONATAL OPIOID WITHDRAWAL SYNDROME; RISK OF MEDICATION ERRORS; and RISK OF SERIOUS HARM OR DEATH WITH CONCOMITANT USE OF CYP3A4 INHIBITORS. DURAGESIC is contraindicated in the management of acute or intermittent pain, or in opioid-non-tolerant patients. Accidental exposure to DURAGESIC may result in fatal respiratory depression.
| Serious Effects |
Hypersensitivity to fentanyl or any component of the patchAcute or postoperative pain (not appropriate for short-term management)Significant respiratory depressionSevere asthma or bronchospasm in an unmonitored settingParalytic ileusUse of MAO inhibitors within 14 days
| Precautions | Life-threatening respiratory depression, especially during initiation or dose escalation, Accidental exposure can be fatal, Risk of abuse, misuse, and addiction, Risks from concomitant use with benzodiazepines or other CNS depressants, Neonatal opioid withdrawal syndrome with prolonged use during pregnancy, Risks of medication errors (e.g., confusion with other fentanyl products), Serotonin syndrome with concomitant serotonergic drugs, Adrenal insufficiency, Severe hypotension, Risks in patients with head injury or increased intracranial pressure, Application site reactions and skin irritation, Wound healing complications in patients with surgical wounds |
| Food/Dietary | Avoid or limit grapefruit juice as it inhibits CYP3A4, increasing fentanyl levels and risk of adverse effects. No other significant food interactions. Alcohol should be avoided as it enhances central nervous system depression. |
| Clinical Pearls | DURAGESIC-12 (fentanyl transdermal system) is indicated for opioid-tolerant patients only. Do not initiate in opioid-naive patients due to risk of fatal respiratory depression. Apply to non-irritated, non-irradiated skin on flat surface such as chest, back, flank, or upper arm. Avoid heat sources (heating pads, hot tubs, fever) which increase absorption. Monitor for constipation and respiratory depression, especially at start and dose titration. Not for acute pain or post-op use in opioid-naive patients. |
| Patient Advice | Apply patch to clean, dry, non-hairy skin; do not cut or damage the patch. · Do not expose patch to direct heat (heating pads, hot tubs, electric blankets). · Keep patch away from children and pets; dispose of used patches by folding adhesive side together and flushing down toilet. · Do not drink grapefruit juice as it may increase fentanyl levels. · Do not stop using patch suddenly as withdrawal symptoms may occur. · Report severe drowsiness, confusion, difficulty breathing, or constipation. · Store at room temperature away from moisture and heat. |
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