Table 1.

Characteristics of Included Case Reports and Case Series

Study ID	Country	No. of Fentanyl-Analogue Death Cases Reported	Study Design	Source of Death	Inferred Route of Administration	Cause of Death	Nature of Death
Brockbals et al 201927	Switzerland	n=1 ● Male ● Age: 39	Case report	Cyclopropylfentanyl	Inhalation	Combined intoxication with ethanol and cyclopropylfentanyl	Unspecified
Butler et al 201728	USA	n=3 ● Male: 3 ● Age range: 23–43	Case report	Acrylfentanyl Furanylfentanyl	Intravenous (n=3)	Acrylfentanyl toxicity (n=1) Toxic effects of acryfentanyl and hydrocodone (n=1) Acryfentanyl and furanylfentanyl toxicity (n=1)	Accidental (n=3)
Castellino et al 202029	USA	n=2 ● Male: 2 ● Age range: 24–25 ● Caucasian	Case report	Cyclopropylfentanyl	Not specified	Cyclopropylfentanyl overdose (n=1) Mixed drug toxicity (n=1)	Accidental (n=2)
Corsi et al 201930	USA	n=17 ● Male: 15 Female: 2 ● Age range: 21–51 ● Caucasian: 15 ● African-American: 2	Case series	Carfentanil	Intravenous (n=5) Undetermined (n=12)	Drug abuse (n=10) Drug intoxication (n=6) Drug overdose (n=1)	Suicide by overdose (n=1) Undetermined (n=17)
Daniulaityte et al 201731	USA	n=281 ● Male: 181 Female: 100 ● Age range: ● White, non-Hispanic: 257 ● Black or other: 24	Case series	Fentanyl Norfentanyl Acrylfentanyl Furanylfentanyl Carfentanil	Unspecified	Drug overdose (n=281)	Accidental (n=281)
Elliott et al 201832	UK	n=7 ● Male: 5 Female: 2 ● Age range: 29–44	Case series	Carfentanil	Intravenous (n=1) Not specified (n=6)	Mixed drug toxicity (n=7).	Undetermined but hinted to be accidental
Fagiola et al 201833	USA	n=5 ● Male: 4 Female: 1 ● Age ranges: 19–49 ● White: 5	Case report	Cyclopropylfentanyl	Intravenous (n=1) Inhalation (n=1) Unspecified (n=3)	Mixed drug toxicity (n=5)	Accidental (n=5)
Gaulier et al 201934	France	n=1 ● Male ● Age: 41	Case report	Carfentanil	Intralingual	Mixed drug toxicity	Accidental
Hikin et al 201835	UK	n=25 ● Male: 22 Female: 3 ● Age range: 21–54	Case series	Carfentanil Butyryl fentanyl 4F-butyryl fentanyl Furanyl fentanyl	Unspecified	Mixed drug toxicity (n=25)	Unspecified
Krotulski et al 201736	USA	n=1 ● Male ● Age: 31 ● White	Case report	Tetrahydrofuranyl-fentanyl	Intravenous	Mixed drug toxicity	Accidental
Moss et al 201937	Western Australia	n=1 ● Male ● Age: 24	Case report	Acetylfentanyl	Intravenous	Acetylfentanyl toxicity	Accidental
O’Donnell et al 201724	USA	n=720 ● Male: 520 Female: 200 ● Age range: <15 – >65 ● White, non-Hispanic: 602 ● Black, non-Hispanic: 75 ● Other, non-Hispanic: 9 ● Hispanic: 20	Case series	Carfentanil Furanylfentanyl Acetylfentanyl	Intravenous (n=303) Inhalation (n=95) Ingestion (n=41) Smoking (n=25) Unspecified (n=279)	● Fentanyl analogue toxicity ● Mixed drug/polydrug toxicity ● Specific numbers unclear	Unspecified
Shanks et al 201738	USA	n=13 ● Male: 8 Female: 5 ● Age range: 25–62	Case report	Carfentanil	Intravenous (n=3) Unspecified (n=10)	Carfentanil drug toxicity (n=7) Mixed carfentanil and fentanyl toxicity (n=2) Mixed drug intoxication (n=4)	Accidental (n=13)
Swanson et al 201739	USA	n=2 ● Male: 2 ● Age range: 25–34 ● White: 2	Case report	Carfentanil Furanylfentanyl	Intravenous (n=1) Unspecified (n=1)	Mixed drug toxicity (n=1) Carfentanil overdose (n=1)	Accidental (n=2)