Study Characteristics
Study type Sample
size 		Methods Dosage of
BT-A 		Age Female/male ratio Time since TN onset
Mean (SD), years Mean (SD)
N
Wu et al. [27] Randomized, double-blind,
placebo-controlled study 		42 Group 1: BT-A
(n = 22) 		75 U 59.14 (12.58) Female: 13 (59.09%) 72.05 (78.48) months
Group 2: (placebo)
isotonic saline (n = 20) 		58 (16.91) Female: 10 (50%) 70 (80.03) months
Shehata et al. [28] Randomized, double-blind,
placebo-controlled study 		20 Group 1: BT-A
(n = 10) 		100 U 45.95 (10.02)
for all participants 		Female: 11/male: 9 5.33 (1.52) years;
range 3 to 9 years
Group 2: (placebo)
0.9% NaCl (n = 10)
Zúñiga et al. [29] Randomized, double-blind,
placebo-controlled study 		36 Group 1: BT-A
(n = 20); 		50 U 64.5 (12.94) Female: 11/male: 9 6.2 (5.01) years
Group 2: (placebo)
0.9% NaCl (n = 16) 		66.06 (14.06) Female: 6/male: 10 5.2 (3.1) years
Zhang et al. [30] Randomized, double-blind,
placebo-controlled study 		80 Group 1: BT-A (25 U)
(n = 25) 		25 and 75 U 58.16 (11.54) Male: 40% 91.96 (72.61) months
Group 1: BT-A (75 U)
(n = 28) 		62.64 (13.32) Male: 42.86% 72.64 (76.45) months
Group 2: (placebo)
0.9% NaCl (n = 27) 		58.41 (11.74) Male: 51.85% 50.96 (46.26) months

N = number; U = units per ml of solution; BT-A = botulinum toxin type A; TN = trigeminal neuralgia.