The veterinarian asks you to administer four drugs. Each has a different route of administration. Drug A must be given PO, drub B must be given IV, drug C must be given SC, and drug D must be given IM. Assuming these drugs are given to normal animals, where should each of these drugs be administered, and which drug will reach its peak plasma concentration the fastest, second fastest, and slowest?
PO meas per os, so it is given by mouth. IV - intravenously, so it is placed within the veins. SQ = subcutaneously so it goes in the tissue beneath the skin. IM goes into the deep belly of a muscle. Obviously the IV drug will reach it speak in the plasma first because all of the drug, if given as a bolus, is placed immediately into the blood (no absorption phase). IM, in muscle that is well perfused and usually moving, is almost as quick to reach its peak concentrations. SQ and PO will be much more variable in their onset of peak concentration because of the various factors that influence their absorption.