Drug administration and dosing regimens

Every medication can be administered through various means, known as routes of administration; and various schedules, meaning at a particular frequency and amount, or dose, which is known as the dosing regimen.

Alright, so routes of administration are broken down into three main categories: enteral, parenteral, and topical. In enteral administration, which is the most common form, the medication is administered through the gastrointestinal tract. This could mean that it’s swallowed by the mouth, also known as peroral administration; placed under the tongue, also known as sublingual administration; between the gums and the inner lining of the cheek, also known as buccal administration; or finally, into the rectum, also known as rectal administration.

On the other hand, parenteral administration includes any route that bypasses the gastrointestinal tract, to pump the medication directly into the circulation, such as through an injection into a vein, intravenously, or IV for short; under the skin, subcutaneously, or SC for short; or into muscle, intramuscularly, or IM for short. Finally, there’s topical administration, where the medication is applied directly upon a particular area of the skin or mucous membrane to achieve a local or systemic effect. An example of this is an antifungal cream used to treat athlete's foot locally or a clonidine patch to treat hypertension systemically.

Now, choosing the route of administration depends on many factors. First of all, these include the chemical properties of the medication itself, such as its stability, and its ability to cross certain barriers of absorption.