The Drug-Induced Respiratory Disease Website and App

Frequency - Incidence

Incidence of respiratory adverse event(s) due to the specific drug as assessed by number of reported/published cases in the literature. Red digits in stars indicate: 0 = Very rare, questionable signal · 1 = < 10 cases · 2 = 10-50 cases · 3 = 50–100 cases · 4 = 100-200 cases · 5 = >200 cases

Evidence level/grade

Evidence level for respiratory adverse event(s) due to the specific drug as estimated using Hill’s (1965), Naranjo’s (1981), and Bégaud’s (1985) criteria applied to published cases. Blue digits in stars indicate: 0 = Questionable · 1 = Low · 2 = Moderate · 3 = Robust · 4 = Definite · 5 = Unquestionable, pathognomonic

IX.d

Respiratory failure from ventilatory depression (due to neuromuscular blockade/paralysis)

Publications

Kusko R, Liss D, House SL, House SB, Krotulski A, Aldy K, Toxicology Investigators Consortium (ToxIC) Fentalog Study Group

An Emerging Synthetic Opioid in the Drug Supply: A Case of Opioid Overdose with Biological Confirmation of Cychlorphine.

Journal of medical toxicology : official journal of the American College of Medical Toxicology. 2026

Raffa RB, Breve F, Pergolizzi JV Jr, Vortsman E, Varrassi G

Cychlorphine (N-Propionitrile Chlorphine): An Emerging Benzimidazolone Synthetic Opioid and Its Implications for Overdose Recognition and Management.

Journal of pain research. 2026;19:620907

Sprague JE, Toms JA, Ratermann CF

Non-fatal opioid overdose associated predominantly with the benzimidazolone, cychlorphine.

Clinical toxicology (Philadelphia, Pa.). 2026;64(2):146-147