Fentanyl is a synthetic opioid agonist, approximately 75-100 times more potent than morphine. The 25 mcg dosage form, typically a transdermal patch, is indicated for the management of persistent, moderate to severe chronic pain requiring continuous, around-the-clock opioid analgesia for an extended period of time. It is a high-alert medication with a narrow therapeutic index and significant potential for misuse, addiction, and fatal respiratory depression.
Adult: Transdermal Patch (25 mcg/hr): For opioid-tolerant patients only. Initial dose based on prior 24-hour opioid requirement using standardized conversion tables (e.g., 90 mg oral morphine/day ≈ 25 mcg/hr fentanyl patch). Apply patch to non-irritated, non-hairy skin on torso or upper arm. Replace every 72 hours. Titrate no more frequently than every 3 days after initial application or every 6 days thereafter.
Note: Apply to clean, dry, non-irritated, non-hairy skin on a flat surface (chest, back, flank, upper arm). Do not shave area; clip hair if needed. Do not use soaps, oils, or lotions on site. Press firmly for 30 seconds. Rotate application sites. Avoid external heat sources (heating pads, hot baths, sun exposure) over patch. Dispose of used patch by folding adhesive sides together and flushing down toilet (as per Indian guidelines for controlled substances) or returning to pharmacy.
Fentanyl is a pure mu-opioid receptor agonist. Its primary therapeutic effects are analgesia and sedation, mediated through agonist activity at the mu-opioid receptors in the central nervous system (CNS), particularly in the periaqueductal gray, locus coeruleus, and the dorsal horn of the spinal cord.
Pregnancy: Category C (US FDA). Prolonged use during pregnancy can cause neonatal opioid withdrawal syndrome (NOWS), which may be life-threatening. Use only if potential benefit justifies potential fetal risk. Not recommended for labor/delivery.
Driving: Severely impairs mental and/or physical abilities required for driving or operating machinery. Patients must be warned not to drive or use machines, especially during initiation and dose titration.
| CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin, Ritonavir, Grapefruit juice) | Markedly increased fentanyl plasma levels, profound sedation, respiratory depression, coma. | Major |
| CYP3A4 Inducers (e.g., Rifampicin, Carbamazepine, Phenytoin, St. John's Wort) | Decreased fentanyl plasma levels, reduced analgesia, potential withdrawal. | Major |
| Other CNS Depressants (e.g., Benzodiazepines, Alcohol, Barbiturates, Other Opioids, Sedating Antihistamines) | Additive CNS depression, profound sedation, respiratory depression, coma, death. | Major |
| Serotonergic Drugs (e.g., SSRIs, SNRIs, TCAs, Tramadol, MAOIs) | Increased risk of serotonin syndrome. | Major |
| Muscle Relaxants | Enhanced neuromuscular blocking action. | Moderate |
| Anticholinergics | Increased risk of urinary retention and constipation. | Moderate |
Same composition (Fentanyl (25mcg)), different brands: