Products
Fentanyl is commercially available in many countries in the form of lozenges, buccal tablets, sublingual tablets, as a fentanyl patch (e.g., Durogesic, generic), and as a solution for injection. It is a narcotic and is subject to enhanced prescription requirements.
Structure and properties
Fentanyl (C22H28N2O, Mr = 336.5 g/mol) exists as a white powder that is practically insoluble in water. In contrast, the salt fentanyl citrate is soluble in water. Fentanyl is an analog of pethidine and a piperidine derivative. It can be administered through the skin and oral mucosa because it is potent at low doses, lipophilic, and a small molecule. This also facilitates its passage across the blood–brain barrier into the central nervous system.
Effects
Fentanyl (ATC N02AB03, ATC N01AH01) has potent analgesic, sedative, and psychotropic properties. The effects are due to agonism at µ-opioid receptors. The analgesic potency is 75-100 times greater than that of morphine; therefore, it can be administered in low doses.
Indications
Fentanyl is used to treat severe pain of various causes. The indications differ depending on the dosage form. The fentanyl transdermal patches are used to treat severe, persistent pain. The lozenges, sublingual tablets, nasal spray, and adhesive tablet have a rapid onset and short duration of action and are used to control pain from breakthrough pain, which is an acute worsening of chronic pain. Intravenously, fentanyl is used for pain control during surgical procedures, anesthesia, trauma, and critical care.
Abuse
Like other opioids, fentanyl can be abused as a depressant and euphoric intoxicant and can become addictive.
Contraindications
Numerous precautions must be observed during use, depending also on the dosage form. Complete lists can be found in the drug label. Contraindications include hypersensitivity, concurrent therapy with MAO inhibitors, respiratory failure, and severe obstructive pulmonary disease.
Interactions
- Fentanyl is a substrate of CYP3A4 and corresponding drug-drug interactions are possible.
- Central depressant drugs and alcohol may potentiate adverse effects.
- Combination with MAO inhibitors is not indicated because serious adverse effects may be induced.
- Opioid antagonists abolish the effects of fentanyl.
- Serotonergic agents increase the risk of serotonin syndrome.
- Anticholinergic agents increase the risk for constipation and urinary retention.
Adverse effects
The most common potential adverse effects of fentanyl patches include nausea, vomiting, constipation, drowsiness, dizziness, and headache. Fentanyl can lead to tolerance, dependence, and withdrawal symptoms if discontinued too quickly. Overdose is life-threatening, especially due to the resulting respiratory depression.The most famous case of fatal fentanyl overdose is the death of musician Prince in April 2016.
