5.3 Medication Routes and Forms

Overview

There are many ways of giving medications and different forms of medications that can be given. Some medications can be given by multiple routes, such as antibiotics, which can be given orally or intravenously. The route and form will depend on the medication, the reason for giving the medication, the availability of the medication, and the patient.

Medication Routes

Inhalation: Breathed into the airway

Intramuscular (IM): Injected into a muscle

Intravenous (IV): Injected into a vein

Example

Intravenous (IV) fluids, shown in Figure 5.4, are routinely used in most surgical procedures in the clinic. IV fluids help maintain a patient’s hydration, but they also offer quick access for the administration of other drugs, including emergency drugs. They even help to maintain the animal’s blood pressure during surgery!

 

Oral (PO): Into the mouth; per os

• This is the most common route used

Subcutaneous (SQ, SC): Injected under the skin

Topical: Applied to the surface or exterior of the body

• This includes ointments, eye drops, and ear medications, among others

Transdermal: Absorbed through the skin

Medication Forms

Drugs are generally formulated into both solid and liquid forms. Solid forms include tablets, capsules, and powders, whereas liquid forms are often categorized based on their route of use.

Solid Formulations

Concentration is generally listed as mg of drug per tablet or capsule or mg per scoop for powder.

• Tablets (tabs): A solid format consisting of an active ingredient, which is the medication, and an inactive ingredient, which consists of fillers and binders so that the medication has a certain shape, size, and colour. Tablets can be hard or in a softer, “chewable” format.

• Capsules (caps): Either in one piece—a liquid medication enclosed in a soft outer layer—or two hard pieces that fit together and are filled with either a powder or small granules

• Powder: Medication in granule form, generally measured with a medication-specific scoop or a measuring spoon

Liquid Formulations

Many medications come in liquid form, and they are categorized based on their route of administration.

• Oral: Liquid that is meant to be given by mouth (PO); can also be a paste
  • Often allows more specific dosing than solid formulations

• Injectable: A liquid that is meant to be injected into the body; generally labelled for IM, IV, or SQ
  • Note: Some liquid drugs can be administered via multiple injectable routes, but some will have negative effects if administered via the incorrect route

Topical: These include liquids, gels, ear medications, and eye drops

• Inhalant: Are generally in liquid form, though sometimes they are aerosolized to become a gas

Common Categories of Drugs

Medications can be separated into different categories depending on their intended use. Understanding the different categories can make it easier to understand why that medication would be prescribed to the patient. Some medications fall into more than one category. Listed below are some common drug categories and their functions (i.e., indications).

Analgesic: Relieves pain

Anesthetic: Produces a lack of sensation

Anti-inflammatory: Reduces inflammation (subcategory: non-steroidal anti-inflammatory drug, or NSAID)

Anthelmintic: Works against intestinal worms

Antibiotic: Inhibits the growth of bacteria or kills bacteria

Anticonvulsant: Prevents seizures

Antidiarrheal: Prevents frequent and loose bowel movements

Antiemetic: Prevents vomiting

Antipruritic: Controls itching

Antiseptic: Kills or prevents the growth of microorganisms on living tissue

Antitussive: Suppresses coughing

Emetic: Induces vomiting

Immunosuppressant: Suppresses or decreases the body’s immune response

Image Credits
(images are listed in order of appearance)

Chemotherapy chemo infusion by klbz, Pixabay licence

Different forms of tablets by Matea David-Steel, NorQuest College. Used with permission.

Soft chewable tablets by Matea David-Steel, NorQuest College. Used with permission.

Medicine capsule blue by Ranys Tuunainen, Pixabay licence

Powdered medications by Matea David-Steel, NorQuest College. Used with permission.

Oral liquid formulation by Matea David-Steel, NorQuest College. Used with permission.

Oral liquid formulation of meloxicam by Matea David-Steel, NorQuest College. Used with permission.

Injection needle disposable by Myriams-Fotos, Pixabay licence

Topical eye medications by Matea David-Steel, NorQuest College. Used with permission.

Topical ear medications by Matea David-Steel, NorQuest College. Used with permission.

Topical liquid formulation by Matea David-Steel, NorQuest College. Used with permission.

Canine inhaler by Apocheir, CC0 1.0