Drug Administration Routes

Drug Administration Routes

There are many methods for administering medication, but only the most common routes will be discussed here. The routes of absorption include enteral, absorbed by the gastrointestinal tract, and parenteral, absorbed outside the gastrointestinal tract.

Enteral Routes

Oral, buccal, sublingual, and rectal are the most common enteral routes of administration.


Oral administration occurs when the medication is taken by mouth, swallowed, and then absorbed via the digestive tract. Some of these medications have an outer layer to withstand the acidity of stomach acid for proper absorption. This is the most common route, as it is usually the least expensive form of medication and easily administered. Typically, this route is used for pain medication such as Tylenol, Hydrocodone, NSAIDs, etc.


Buccal administration involves the medication being placed between the gum and cheek. This route may be used when the chemical property of the medication requires a certain pH level for optimal strength. The pain medication, fentanyl, has a form that is given by buccal route for maximal results in relation to pH level of this route.


Sublingual administration is the route in which the medication is absorbed under the tongue. There are thousands of blood vessels in this area, and sublingual administration is used when fast absorption of the medication is needed. An example of this is Nitroglycerin which is given for chest pain.


Rectal administration of a medication is the insertion of the drug into the rectum where it is then absorbed by the intestinal tract. This route is used when direct access to the intestines are needed. Suppositories are given by this route to more quickly treat constipation as the medication melts at body temperature and then signals for the body to empty the intestines more sufficiently.

Parenteral Routes

Intravenous, intramuscular, topical, otic, conjunctival, nasal, inhalation, and subcutaneous are parenteral routes of administration.


The intravenous route of medication is given directly into a vein. There are many reasons to use this route, including direct access to the bloodstream for fast absorption of the medication. It is most commonly used for the administration of fluids like normal saline and lactated ringers.


The intramuscular route is by way of injection directly into the muscle for absorption. It is considered less hazardous and stays in the blood longer than the intravenous route. The flu vaccine is given this route as it lessens adverse reactions as well as improves the effectiveness of the vaccine.


Topical is another route of administration where the medication is applied directly to and absorbed via the top layer of skin. This route is used when a specific area on the skin needs to be treated. Steroids can be given using this route for conditions such as eczema and psoriasis.


The otic, also known as auricular, route consists of administration via the ear canal. This route is typically used for the specific site. Cleaning and pain medication for the ear are given using this pathway.


Conjunctival route is the administration of medication to the outer layer that covers the eye and eyelid. This medication route is given for maximum absorption directly by that site. One example includes drops to dilate the eye for surgery.


Nasal or intranasal administration is delivering medication via the nostril. Some reasons for this particular route include ease of administration, direct access to the bloodstream without intravenous access, and rapid ascent to desired levels in the brain/CSF. One medication administered via this method is naloxone, which is a reversal agent for an opioid overdose.


Inhalation is the route in which the medication is breathed directly into the pathway to the lungs. This route is typically used for direct administration to the organ desired, the lungs, and it is used in pediatric patients for easier medication delivery. Medication delivered by this route has a lower strength than the same drug delivered by systemic routes, thus fewer side effects. Inhalers used for asthma or breathing treatments to open up the lungs are examples of the use of this route.


The subcutaneous route is the injection of medication into the subcutaneous layer of the skin, the fatty tissue between the skin and muscle. The abdomen and the fatty tissue surrounding the triceps muscle are the most common areas used for administration. Insulin is given this route due to gradual absorption rather than flooding the body instantly and causing a significant drop in glucose levels.

Drug Administration Routes

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