FEN-ta-nil 
Contraindicated in:
Use Cautiously in:
CV: bradycardia, hypotension.
Derm: sweating, erythema.
Endo: adrenal insufficiency.
GI: anorexia, constipation, dry mouth, nausea, vomiting.
Local: application site reactions.
MS: skeletal and thoracic muscle rigidity.
Neuro: confusion, sedation, weakness, dizziness, restlessness.
Resp: APNEA, bronchoconstriction, laryngospasm, RESPIRATORY DEPRESSION (INCLUDING CENTRAL SLEEP APNEA AND SLEEP-RELATED HYPOXEMIA).
Misc: physical dependence, psychological dependence.
Drug-Drug:
Drug-Natural Products:
Drug-Food:
(Generic available)
Hepatic Impairment
Renal Impairment
Absorption: Well absorbed (92% of dose) through skin surface under transdermal patch, creating a depot in the upper skin layers. Release from transdermal system into systemic circulation ↑ gradually to a constant rate, providing continuous delivery for 72 hr.
Distribution: Crosses the placenta; enters breast milk.
Metabolism/Excretion: Mostly metabolized by the liver via the CYP3A4 isoenzyme; 10–25% excreted unchanged by the kidneys.
Half-life: 17 hr after removal of a single application patch, ↑ to 21 hr after removal of multiple patches (because of continued release from deposition of drug in skin layers).
(↓ pain)
| ROUTE | ONSET | PEAK | DURATION |
|---|---|---|---|
| Transdermal | 6 hr† | 12–24 hr | 72 hr‡ |
†Achievement of blood levels associated with analgesia. Maximal response and dose titration may take up to 6 days.
‡While patch is worn.
NDC Code*