Dosage Forms / Routes of Administration

Enteral   |   Parenteral   |  Transdermal   |   Inhalation

Dosage forms, also known as Routes of administration describe the physical form in which medication will be delivered into the body.

Common dosage forms

Enteral medications are given orally and pass through the GI tract to be absorbed into the bloodstream and metabolized by the liver. This includes oral, naso-gastric, and rectal routes.

Parenteral medications are injected or placed into the body tissues and do not pass through the liver before entering the bloodstream. This can include injections, topical and inhalation routes. Generally in pharmacy, parenteral refers to injection. Topical and inhalation routes are separated into their own routes of administration.

Injectable drugs are usually in the form of solutions or powders, which are mixed with a sterile diluent to render an injectable solution.

Inhalation routes of administration are inhaled through the mouth or the nose and usually act directly on the respiratory system before entering into the bloodstream. They are often used to treat respiratory diseases, but gases are inhaled for general anesthesia as well.

Topical dosages are applied to the skin surface or a mucous membrane.

Dosage Form Table:

Oral Preparations
Tablets To form a Tablet the drug is combined with fillers and is then compressed into a hard pellet. There are various shapes, sizes and colors of tablets. Tablets are available in fast acting, slow release, controlled release, enteric coated, film coated, sublingual, chewable and other formulations. Not all oral Dosage Forms / tablets are swallowed.
Sublingual (SL) tablets are placed under the tongue, wafers are placed on the tongue and BUCCAL tablets are placed between the cheek and the gum.
Capsules To form a Capsule the drug is contained in a cylindrically shaped shell, which breaks open and the drug is released. This includes gelatin capsules.
Caplet A Caplet is an oval-shaped tablet.
Oral Solutions The drug is dissolved completely into a liquid form.
Oral Suspensions The drug is mixed with, but not completely dissolved into a liquid. It needs to be shaken before administration in order to suspend the drug particles evenly.
Syrups Contain a high concentration of sucrose or sugar to sweeten, for ease of use.
Elixirs Elixirs contain between 5% and 40% alcohol.
Tinctures May contain as little as 17% alcohol or as much as 80% alcohol.
Emulsions An Emulsion is a suspension involving one liquid in a second liquid with which the first will not mix. (oil in water or water in oil)
Oral powders Drugs which are in a powder form and are usually dissolved in juice or water before administration
Lozenge and Troche Lozenges and Troches are meant to be dissolved slowly in the mouth and generally have a local effect.
Rectal Suppositories Solid or semi-solid bullet shaped dosage forms. They melt at body temperature, dispersing the medication.
Enemas Drug is suspended in a solution and infused into the rectum.
Transdermal patch A medicated adhesive patch applied directly on the skin to deliver a specific dosage of a drug. They have systemic effects and should be rotated to different sites on the body.
Inhalation Inhaled through the mouth or nose and usually act directly on the respiratory system before entering into the bloodstream. They are often used to treat respiratory diseases, but gases are inhaled for general anesthesia as well.

Injectable Preparations
Epidural Injected into the dura matter (epidural space) of the spinal cord.
Intravenous Injected into the vein. This allows for immediate adsorption. Intravenous includes IV push, IV piggyback and IV infusion or drip.
Intramuscular Injected into the muscle.
Subcutaneous Injected into the fatty layer under the skin.
Intradermal Injected into the top layer of the skin at a slight angle.
Intracardiac Injected into the heart.
Intraocular Injected within the eye.
Intrathecal Injected into the space surrounding the spinal cord.
Intra-articular Injected into the joint.
These are not all of the Dosage Forms used in modern medical practice, but a brief list of the most common seen by pharmacy technicians. The routes of administration here are the more common forms and should be memorized to prepare for the pharmacy tech test.

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