The intravenous (IV) route of administration can deliver a fast-acting effect, which is vital in emergency situations. IV medications are also useful for pain management and are more easily absorbed compared to the other route of parenteral administration.
The IV route carries the greatest risk of any of the parenteral routes for drug administration. By administering directly into the systemic circulation, the drug is instantaneously distributed to its sites of action. If medications are given too quickly or incorrectly, significant damage may occur. Reactions can occur, as well as the possibility of damage to the surrounding tissues. It is important to remember that IV medications should never be administered in the same IV line that is infusing blood, blood products, heparin IV, insulin IV, or parenteral nutrition solutions.
Common injection sites include the deltoid muscle in the arm, the vastus lateralis muscle of the thigh, the ventrogluteal muscle of the hip (which is the safest site for adults and children over the age of seven months, as it’s deep and not close to any major blood vessels and nerve), and the dorsogluteal muscles of the buttocks, which used to be the commonly selected site, but is not recommended as it has risk for injury because of proximity to the sciatic nerve.
Intramuscular (IM) injections may be used instead of IV because some drugs are irritating to veins, and/or it may be used instead of oral administration because some drugs are destroyed by the digestive system when a drug is swallowed. The intramuscular injections are absorbed faster than subcutaneous injections, because muscle tissue has a greater blood supply, as well as being able to hold a larger volume of medication than subcutaneous tissue.
Common medications administered IM include vaccines, such as the flu shot. Epinephrine, which comes in an automated injector form (EpiPen) is intended to be administered via IM, but can be administered subcutaneously as well.
There should be no more than 3 mL of medication administered into an IM injection site, and for the deltoid, the limit is 2 mL.
The drug administration for an SC injection needs to be injected into the fatty tissue just below the skin. The most common injection sites are the abdomen (about two inches away from the navel) the arm (the back or side of the upper arm) or the front of the thigh.
Subcutaneous (SC or SubQ) means under the skin. With this type of medication administration is where a short needle is used to inject a drug into the tissue layer between the skin and the muscle. SC injections are absorbed more slowly than if injected into a vein, sometimes over a period of 24 hours. This type of administration may be used instead of oral administration because some drugs are destroyed by the digestive system when a drug is swallowed.
Commonly administered SC medications are insulin and hormones. It is important to note that the nurse should rotate administration sites when giving SC injections.
Medications administered by subcutaneous injection include drugs that can be given in small volumes (1 mL, but up to 2 mL is safe).
The most common sites for this injection is the back of the forearm, and the upper back, under the scapula.
Intradermal injections (ID) are administered into the dermis, below the epidermis. Medication administered into the dermis is absorbed slowly because of the limited blood supply of the skin, so of all the parenteral routes, it is the longest absorption time.
These injections are given for diagnostic purposes, such as tuberculosis or allergy testing, and the reactions are easy to visualize.
The dosage for ID injections is usually under 0.5 mL. Aspiration is not needed for intradermal administration as the dermis is without vessels, relatively. Do not massage the area after an ID injection, as it may spread the solution to the subcutaneous tissue.
Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.
*Average video play time: 2-3 minutes
Unforgettable characters with concise but impactful videos (2-4 min each)