Discussion
pain
COMPLICATIONS
The findings of this study indicated that the addition of lidocaine (without epinephrine) to botulinum toxin might reduce pain while at the same time, might not increase any complications of injection. There is no similar study that assesses the findings of the current study. There are however, two clinical series and two controversial clinical trial studies on the effect of dilution of botulinum toxin with lidocaine plus epinephrineUpon injection of botulinum toxin, pain can be felt in two stages, once when the needle punctures the skin and tissues and later after the toxin is injected into the tissue. The needle pain can be alleviated by locally anesthetizing the skin using methods such as the EMLA (eutectic mixture of local anesthetics) cream or ice packsThis study was limited by some factors. The number of men was much smaller than the number of women; this was similar to all other studies on botulinum toxin, in which much more women seek such treatments. However, given the very large sample size, even the current number of men may be adequate to obtain proper results. Moreover, the number of one of the brands in use was smaller than the other brand, due to market availability. Furthermore, it would be better to also have positive control groups, in which the toxin was mixed with lidocaine and adrenaline. Nevertheless, that would require about 200 to 300 additional participants, which was not practical. The generalizability of the results may be increased by using various brands of botulinum toxin and enrolling more men. Nevertheless, it may be limited by the ethnic background of the participants, as in any other study.