It is not usually necessary to try to sterilize the skin with antiseptics – their use is almost always ineffective and they simply prolong the duration of restraint needed and may cause additional disturbance to the animal.
As with all injection sites, a new needle should be used for each animal, since this will reduce discomfort caused by the procedure and also reduce this risk of any injection-site infection. Any discomfort can be further reduced by injecting fluid that is at body temperature.
Material that is irritant or with a high or low pH can cause pain both during and following injection.