A potent narcotic analgesic, abuse of which leads to habituation or addiction. It is primarily a mu-opioid agonist. Fentanyl is also used as an adjunct to general anesthetics, and as an anesthetic for induction and maintenance. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1078)
Fentanyl is an opioid analgesic. Fentanyl interacts predominately with the opioid mu-receptor but also binds to kappa and delta-type opioid receptors. These mu-binding sites are discretely distributed in the human brain, spinal cord, and other tissues. In clinical settings, Fentanyl exerts its principal pharmacologic effects on the central nervous system. Its primary actions of therapeutic value are analgesia and sedation. Fentanyl may increase the patient’s tolerance for pain and decrease the perception of suffering, although the presence of the pain itself may still be recognized. In addition to analgesia, alterations in mood, euphoria and dysphoria, and drowsiness commonly occur. Fentanyl depresses the respiratory centers, depresses the cough reflex, and constricts the pupils.
Fentanyl has an LD50 of 3.1 milligrams per kilogram in rats, and, 0.03 milligrams per kilogram in monkeys. The LD50 in humans is not known.
Imprints

Drug: Fentanyl
Strength: 100 Mcg (base)
Pill Imprint: WPI 3571
Color: White
Shape: Round
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Drug: Fentanyl
Strength: 200 Mcg (base)
Pill Imprint: WPI 3572
Color: White
Shape: Round
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Drug: Fentanyl
Strength: 800 Mcg (base)
Pill Imprint: WPI 3575
Color: White
Shape: Round
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Drug: Fentanyl
Strength: 600 Mcg (base)
Pill Imprint: WPI 3574
Color: White
Shape: Rectangle
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Drug: Fentanyl
Strength: 400 Mcg (base)
Pill Imprint: WPI 3573
Color: White
Shape: Round
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Drug: Fentanyl
Strength: 800 Mcg (base)
Pill Imprint: 8
Color: Purple
Shape: Capsule-shape
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Drug: Fentanyl
Strength: 200 Mcg (base)
Pill Imprint: 2
Color: Orange
Shape: Elliptical / Oval
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Drug: Fentanyl
Strength: 300 Mcg (base)
Pill Imprint: 3
Color: Brown
Shape: Three-sided
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Drug: Fentanyl
Strength: 400 Mcg (base)
Pill Imprint: 4
Color: Purple
Shape: Four-sided
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