Study Facial asymmetry/disappearance
time 		Other side effects
BT-A Placebo
N N N
Wu et al. [27] 5 patients/
in 7 weeks 		0

Transient oedema in the area of injection was observed in 3 patients
(2 in the BT-A group and 1 patient from the placebo group),
facial oedema developed in 2 days and disappeared within 7 days.

Shehata et al. [28] 4 patients/- 0 Haematoma BT-A 1 and placebo 2
Itching BT-A 1 and placebo 1
Pain BT-A and placebo 1
Zúñiga et al. [29] 2 patients/- 0 Haematoma at the site of administration (2 patients in BT-A group).
Zhang et al. [30] 3 patients/
in 6 weeks 		0 Transient oedema in the injection was observed in 2 patients (both from BT-A 25 U group) and disappeared within 5 days.

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