Final answer:
The nurse should inject the medication slowly to limit discomfort when administering an injection to an adult.
Step-by-step explanation:
To limit discomfort when administering an injection to an adult, the nurse should inject the medication slowly. This allows the medication to be absorbed more gradually and reduces the sensation of pain or discomfort. Pulling back on the plunger before injecting the medication is not recommended as it can cause tissue damage and leakage of medication. Applying ice to the area before the injection may numb the area temporarily, but it does not prevent discomfort during the injection itself. Pinching the area while inserting the needle can cause additional pain and discomfort.