Fentanyl (IV/Nasal/Buccal — Non-Patch)

Opioidprescriptioniv · predicted

Extremely potent synthetic mu-opioid agonist (50-100x morphine). Rapid-onset non-patch formulations (IV, nasal, buccal). IV onset 1-2 min, nasal/buccal 5-10 min. Context-sensitive half-life (2-7h) — accumulates with prolonged infusion due to distribution into deep compartments. High first-pass effect → negligible oral bioavailability. Chest wall rigidity ("wooden chest syndrome") is a distinctive and potentially fatal adverse effect unique to high-potency fentanyl analogs. Leading cause of opioid overdose deaths in the US opioid crisis. Note: fentanyl_patch.yaml covers the transdermal formulation; this entry represents rapid-onset non-patch forms.

Projected serum levels — 0.050 mg, as needed (shown daily)

Maintenance schedule: 0.050 mg as needed (shown daily) (iv).

Modeled steady state after ~1 days: peak ≈ 0.015 mg, trough ≈ 0.001 mg body load. Population-based estimate over 15 days for a 0.050 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category: Opioid
Route modeled: IV
Model confidence: predicted
Half-life: 3.5 h
Common dose: 0.050 mg
Suggested maximum: 0.20 mg/day
Reference dose range: 0.025–0.20 mg (single dose)
Suggested cadence: as needed (shown daily)

Documented interactions

contraindicated
Clarithromycin (Biaxin) + Fentanyl (IV/Nasal/Buccal — Non-Patch) CYP inhibition
Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Fentanyl (IV/Nasal/Buccal — Non-Patch) AUC by ~6.79x
contraindicated
Diltiazem + Fentanyl (IV/Nasal/Buccal — Non-Patch) CYP inhibition
Diltiazem mechanism_based of CYP3A4 predicted to change Fentanyl (IV/Nasal/Buccal — Non-Patch) AUC by ~6.79x
contraindicated
Efavirenz (Sustiva) + Fentanyl (IV/Nasal/Buccal — Non-Patch) CYP induction
Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Fentanyl (IV/Nasal/Buccal — Non-Patch) AUC by ~0.13x
contraindicated
Grapefruit (whole fruit) + Fentanyl (IV/Nasal/Buccal — Non-Patch) CYP inhibition
Grapefruit (whole fruit) mechanism_based of CYP3A4 predicted to change Fentanyl (IV/Nasal/Buccal — Non-Patch) AUC by ~6.79x
contraindicated
Grapefruit Juice + Fentanyl (IV/Nasal/Buccal — Non-Patch) CYP inhibition
Grapefruit Juice mechanism_based of CYP3A4 predicted to change Fentanyl (IV/Nasal/Buccal — Non-Patch) AUC by ~6.79x
contraindicated
Paxlovid (Nirmatrelvir/Ritonavir) + Fentanyl (IV/Nasal/Buccal — Non-Patch) CYP inhibition
Paxlovid (Nirmatrelvir/Ritonavir) mechanism_based of CYP3A4 predicted to change Fentanyl (IV/Nasal/Buccal — Non-Patch) AUC by ~6.79x

Serum checks 97 modeled interaction pairings for fentanyl (iv/nasal/buccal — non-patch) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

CDC Clinical Practice Guideline for Prescribing Opioids for Pain — United States, 2022 Dowell D et al. · MMWR Recommendations and Reports, 2022 DOI
Updated CDC guideline documenting the fentanyl-driven opioid crisis — illicitly manufactured fentanyl (non-patch forms) is the primary driver of US overdose deaths, with >70,000 synthetic opioid deaths in 2021.
Fentanyl pharmacokinetics and pharmacodynamics Lotsch J et al. · Clinical Pharmacokinetics, 2004 DOI
Definitive review of fentanyl PK/PD establishing context-sensitive half-life, CYP3A4 metabolism, protein binding (~85%), and the clinical implications of rapid onset for respiratory depression and chest wall rigidity.

2 published studies referenced in the app, each with a plain-language summary.