Which Principle of Drug Administration Will You Include in the Teaching

Which principle of drug administration will you include in the teaching plan of a patient who will be administering his own subcutaneous injections?

A) Rotate sites among the upper arm, abdomen, and anterior thigh.
B) Avoid injecting within 3 inches of a previous injection site.
C) Insert the needle at a 30-degree angle to the skin.
D) Use a 22-gauge, 5/8-inch needle.