FENTANYL CITRATE AND DROPERIDOL
Clinical safety rating: avoid
CNS depressants including alcohol and benzodiazepines increase sedation risk Life-threatening respiratory depression may occur.
Fentanyl is a mu-opioid receptor agonist, producing analgesia and sedation. Droperidol is a butyrophenone antipsychotic that blocks dopamine D2 receptors in the brain, causing tranquilization and antiemetic effects.
| Metabolism | Fentanyl primarily metabolized by CYP3A4 to norfentanyl; Droperidol mainly metabolized by CYP2D6 and CYP3A4 to various metabolites. |
| Excretion | Fentanyl: primarily renal (75% as metabolites, <10% unchanged), with about 9% excreted in feces. Droperidol: renal (75% as metabolites, <1% unchanged), about 22% in feces. |
| Half-life | Fentanyl: 3-4 hours (terminal elimination half-life); prolonged in elderly and hepatic impairment. Droperidol: 2.2-2.5 hours (terminal elimination half-life). |
| Protein binding | Fentanyl: 80-85% bound primarily to albumin and alpha-1-acid glycoprotein. Droperidol: 85-90% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Fentanyl: 3-5 L/kg (large Vd due to lipophilicity, extensive tissue distribution). Droperidol: 2-4 L/kg (moderate Vd). |
| Bioavailability | Fentanyl: buccal/transmucosal 50-90%, transdermal ~30-50%, oral <15% (first-pass effect). Droperidol: intramuscular ~60-70%, oral <60% (first-pass effect). |
| Onset of Action | Intravenous: fentanyl onset 30-60 seconds, droperidol onset 3-10 minutes. Intramuscular: fentanyl 7-15 minutes. |
| Duration of Action | Fentanyl: 30-60 minutes (IV) due to redistribution; prolonged with high doses or continuous infusion. Droperidol: 2-4 hours (IV/IM) for sedative effects; antiemetic effects up to 12 hours. |
| Molecular Weight | 336.5 g/mol (fentanyl), 379.4 g/mol (droperidol) |
Fentanyl 50-100 mcg IV and droperidol 2.5-5 mg IV, administered slowly over 1-2 minutes, repeated every 60 minutes as needed for breakthrough pain or sedation.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for fentanyl citrate; droperidol is primarily hepatically metabolized. Use caution in severe renal impairment (eGFR <30 mL/min) due to potential accumulation of inactive metabolites. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce fentanyl dose by 50% and droperidol dose by 50%. Child-Pugh C: avoid use or reduce fentanyl to 25% and droperidol to 25% with careful monitoring. |
| Pediatric use | Not recommended for children under 12 years due to risk of extrapyramidal effects from droperidol. For adolescents 12-16 years: fentanyl 0.5-1 mcg/kg IV and droperidol 0.01-0.02 mg/kg IV, maximum single dose fentanyl 100 mcg and droperidol 2.5 mg. |
| Geriatric use | Reduce initial doses by 50% (fentanyl 25-50 mcg IV, droperidol 1.25-2.5 mg IV) due to increased sensitivity to opioids and anticholinergic effects; titrate slowly with monitoring for hypotension, respiratory depression, and QT prolongation. |
| 1st trimester | Avoid unless clearly needed; may be associated with neural tube defects in animal studies. |
| 2nd trimester | Use only if benefit outweighs risk; no well-controlled human studies. |
| 3rd trimester | Prolonged use may lead to neonatal opioid withdrawal syndrome; use only if clearly needed. |
Clinical note
CNS depressants including alcohol and benzodiazepines increase sedation risk Life-threatening respiratory depression may occur.
| FDA category | Positive |
| Placental transfer | Both fentanyl and droperidol cross the placenta; fentanyl transfer is rapid and significant. |
| Breastfeeding | Both fentanyl and droperidol are excreted in breast milk in low amounts. Monitor infant for respiratory depression, sedation, and poor feeding. Generally compatible with short-term use, but avoid chronic administration. |
■ FDA Black Box Warning
Droperidol may cause QT prolongation and torsades de pointes; use contraindicated in patients with known or suspected QT prolongation (QTc > 440 ms in males, > 450 ms in females) or those at risk. Fentanyl has risk of respiratory depression, particularly in opioid-naive patients.
| Common Effects | Constipation |
| Serious Effects |
Hypersensitivity to fentanyl, droperidol, or any componentConcurrent use of MAOIs or within 14 days of stoppingSevere respiratory depression (unmonitored)QT prolongation (for droperidol component)
| Precautions | Risk of respiratory depression, QT prolongation, hypotension, bradycardia, bronchospasm, and extrapyramidal symptoms. Use with caution in patients with COPD, head injury, renal/hepatic impairment, elderly, debilitated, or on MAOIs. |
| Food/Dietary |
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| Lactation Rating | L3 - Moderately Safe |
| Teratogenic Risk | Fentanyl: Limited human data; animal studies show no teratogenicity at clinically relevant doses. Risk of neonatal opioid withdrawal syndrome with prolonged third-trimester use. Droperidol: Not teratogenic in animal studies; human data insufficient. First trimester: theoretical risk, limited data. Second trimester: no specific risk identified. Third trimester: fentanyl may cause fetal respiratory depression and withdrawal; droperidol may cause extrapyramidal signs in neonate. |
| Fetal Monitoring | Monitor maternal respiratory rate, oxygen saturation, blood pressure, and heart rate. Fetal monitoring: continuous fetal heart rate monitoring during labor. Assess neonatal respiratory effort and Apgar scores post-delivery. Observe for neonatal opioid withdrawal syndrome if prolonged maternal use. |
| Fertility Effects | Fentanyl: No direct effects on fertility in human studies; opioid use may disrupt menstrual cycle and reduce libido. Droperidol: May cause hyperprolactinemia leading to menstrual irregularities and galactorrhea; clinical significance uncertain. No specific data on fertility with combination. |
| No specific food interactions are reported for fentanyl citrate or droperidol. However, grapefruit juice may increase fentanyl levels via CYP3A4 inhibition; consider avoidance during therapy. Avoid alcohol due to additive CNS depressant effects. St. John's wort may reduce fentanyl efficacy. General dietary advice: maintain adequate hydration to prevent constipation from fentanyl. |
| Clinical Pearls | Fentanyl citrate and droperidol combination is used for neuroleptanalgesia. Fentanyl is a potent synthetic opioid mu-agonist with rapid onset (1-2 min IV) and short duration (30-60 min). Droperidol is a butyrophenone antipsychotic with antiemetic and sedative properties. Monitor for respiratory depression, chest wall rigidity (fentanyl), and QT prolongation (droperidol). Droperidol carries a black box warning for QT prolongation and torsades de pointes; obtain baseline ECG and monitor electrolytes. Use in a monitored setting with resuscitation equipment. This combination may cause hypotension, especially in hypovolemic patients. Naloxone can reverse fentanyl effects; droperidol effects may persist. |
| Patient Advice | This medication will cause drowsiness and dizziness; do not drive or operate machinery for at least 24 hours after administration. · Avoid alcohol and other central nervous system depressants while under the effects of this drug. · Report any difficulty breathing, chest tightness, or fainting spells immediately. · You may experience nausea, but this medication contains an antiemetic; report persistent nausea or vomiting. · Do not take any other medications, including over-the-counter drugs, without consulting your healthcare provider. · This drug may cause constipation; stay hydrated and consume fiber-rich foods unless otherwise instructed. · If you have a history of heart rhythm problems, inform your healthcare provider before receiving this drug. |