SubQ: Abbreviation for subcutaneous.
Subcutaneous means under the skin. It implies just under the skin.
With a subcutaneous injection, a needle is inserted just under the skin. A drug (for example, insulin) can then be delivered into the subcutaneous tissues. After the injection, the drug moves into small blood vessels and the bloodstream. The subcutaneous route is used with many protein and polypeptide drugs such as insulin which, if given by mouth, would be broken down and digested in the intestinal tract.