Medication can be administered to the body in many different ways. Orally (taken by mouth), sublingually or buccally (placed under the tongue or between the gums and cheek), rectally or vaginally (inserted into the rectum or vagina), ocular or otic route (placed in the eye or ear), nasally (sprayed into the nose and absorbed via the nasal membranes), inhalation or nebulization (breathed into the lungs by the mouth or nose), cutaneously (applied to the skin), transdermally (delivered through a skin patch), or via injection.
When it comes to the administration of drugs via injection, there are a few different ways that it can be done: Intravenously, intramuscularly, subcutaneously, or intrathecally.
Intravenous (IV): Drugs that are administered intravenously are typically done in a hospital setting and go directly into a vein using a needle or thin plastic tube known as an IV catheter. This catheter allows for you to receive multiple doses of medication without having to be poked with a needle each time. Along with being able to have multiple doses of a medication, intravenous administration is also beneficial as it allows your bloodstream to get the medication it needs quickly – which can be beneficial in emergency situations such as heart attacks and strokes. Drugs can also work better when given intravenously, as when you take them by mouth, your stomach enzymes and liver tend to break them down.
A standard IV line is used for two types of medication administration: An IV push, in which a rapid, one-time dose of medication is given to you; or IV infusion, in which there is controlled administration of medication given to you over time. If you require long-term treatment of a specific medication, such as chemotherapy, this will often require something known as a CVC (central venous catheter) instead of the standard IV catheter. A CVC can be inserted into a vein in your arm, neck, chest, or the groin area, and can remain in place for several weeks or even months.
Intramuscular (IM): This is an injectable technique in which a medication is delivered deep into the muscles, also allowing for the bloodstream to absorb it quickly. Vaccines, such as the flu shot, is one example of an intramuscular injection. Certain drugs used to treat conditions such as MS or rheumatoid arthritis can also be given via IM. The most common site used for an intramuscular injection is the deltoid muscle, which is located in the uppermost part of the arm and close to the shoulder. It can also be administered through the vastus lateralis muscle of the thigh (this is the easiest location to administer an IM injection if you have to do it on your own), or administered via the ventrogluteal muscle of the hip or dorsogluteal muscles of the buttocks.
If you are going to give yourself an intramuscular injection, it’s important that you have received proper training and education on technique. Prior to giving the injection, you should also clean the area with an alcoholic swab and allow a few seconds for it to dry. The type of needle size you should use is dependent on the age of the individual reading the direction, as well as the volume and type of medication that is being administered – though it’s generally suggested that adults use needles that are 1 to 1.5 inches / 22 to 25-gauge in thickness.
Subcutaneous (SC/SQ/SubQ): Unlike intramuscular (IM) injections, a subcutaneous injection is used with a shorter needle that injects the medication into the layer of tissue between the skin and muscle. Drugs that are administered subcutaneously generally absorb slower than medications that are given intravenously.
Examples of subcutaneous injections include medications like insulin, epinephrine (this can work when given both as a subcutaneous injection or intramuscular injection), certain pain medications such as Dilaudid, medications that are used to prevent nausea such as metoclopramide, as well as certain vaccines and allergy shots.
The most common locations for a subcutaneous injection include the back or side of the upper arm, the front of the thigh, or the abdomen (located at or just under the belly button, a couple of inches away from the navel.)
Intrathecal: Intrathecal administration is when drugs are administered via injection directly into the spinal canal or subarachnoid space, so that it reaches the cerebrospinal fluid (also known as CSF.) Intrathecal injections are used for spinal anesthesia, chemotherapy, as well as those used for pain management and fighting infections.