. 2023 May;385(2):117–134. doi: 10.1124/jpet.122.001476

TABLE 4.

Duration of effect of acute heroin and fentanyl following chronic fentanyl withdrawal in minutes

			Duration (Min)
Acute Drug	Chronic Treatment	Sex	Minute Ventilation	Tidal Volume	Frequency	Peak Inspiratory Flow	Inspiratory Time	Apneic Pause
Heroin	Fentanyl	Female	10^a	5^a	15^a^,^b	20^a	20^b^,^c	NA
		Male	0	0	0	20^a	40^b	NA
	Saline	Female	25^a	5^a	20^a^,^b	35^a	45^c	20^c
		Male	10^a	5^a	NA	30^a	50^c	NA
Fentanyl	Fentanyl	Female	0	5^a	10^a	10^a	15^c	5^b^,^c
		Male	0	0	5^a^,^b	10^a	15^c	10^c
	Saline	Female	10^a	0	15^a	15^a	15^c	15^c
		Male	5^a	5^a	5^a^,^b	10^a	15^c	10^c

NA, not applicable.

Post hoc comparisons following one-way ANOVA separated by sex and dose.

^aP < 0.05, decreased from baseline (direction of respiratory depression for minute ventilation, tidal volume, frequency, and peak inspiratory flow).

^bLate onset.

^cP < 0.05, increased from baseline (direction of respiratory depression for inspiratory time and apneic pause).