Table 2.

Fentanyl-induced cough and its severity in the four groups

Group		I (n = 100)	II (n = 100)	III (n = 100)	IV (n = 100)	P
Cough (n, %)		40 (40)	12 (12)*,†,#	4 (4)*,†	0 (0)*
Severity	Mild	25	8	3	0	<0.001
	Moderate	10	4	1	0
	Severe	5	0	0	0

Data are presented as numbers.

^*P<0.05 vs Group I;

^†P<0.05 vs Group IV;

^#P<0.05 vs Group III.

The severity of cough was graded: none (0), mild (1-2), moderate (3-4), or severe (5 or more).