3 Dosage Forms and Routes

How form and route work together

A dosage form describes the medicine’s physical preparation; the route of administration describes how it enters or contacts the body. Together, form and route affect how a product is prepared, measured, administered, stored, and dispensed.

A drug may be available in more than one form or route, but products should not be treated as interchangeable unless the labeling or a qualified prescriber or pharmacist confirms they are. Dosage-form terminology includes many forms, including delayed-release and extended-release tablets, capsules, and liquids.

Common dosage forms

Solid and liquid preparations

Tablets and capsules are solid forms commonly taken by mouth. Some tablets are chewable, orally disintegrating, or designed to release medicine over time. Check the directions before splitting, crushing, or chewing a tablet or opening a capsule.

In a solution, the drug is dissolved in liquid, so the preparation is generally uniform. Measure oral liquid doses with an appropriate oral syringe or dosing device, not a household spoon.

A suspension contains drug particles dispersed in liquid, and the particles may settle. Shake it as directed before measuring so the dose is consistent. Some suspensions and other products require reconstitution before dispensing or use; follow the product’s instructions for water volume, storage, and beyond-use period. Emulsions and syrups are liquid preparations with distinct ingredients or a sweetened vehicle; follow the label for shaking, measuring, storage, and use.

Preparations for body surfaces and cavities

Creams, ointments, gels, and lotions are semisolid or liquid preparations applied to the skin or another specified surface. Use them only at the intended labeled site: a skin product is not automatically appropriate for the eye, mouth, or another body site.

Suppositories and inserts are solid forms placed into a specified body cavity, such as the rectum or vagina, where they dissolve or release medicine. Confirm the intended route before dispensing or use.

Delivery systems and sterile preparations

Patches and other drug-delivery systems deliver medicine through or at a specified body site, sometimes over an extended period. Apply and remove them as directed, and do not cut a patch unless its labeling specifically permits it.

Inhalers and sprays deliver measured amounts as aerosols or powders to the lungs, or may be intended for the nose or another site. Correct device technique is essential, and different devices may require different steps.

Injections and infusions are sterile preparations given by a specified route, such as intravenous, intramuscular, or subcutaneous. The route, preparation, and administration instructions must match the product labeling.

Major administration routes

Oral medicines are swallowed for action in the gastrointestinal tract or after absorption into the body. Tablets, capsules, and liquids are among the oral forms. Consider swallowing ability, dose-measuring needs, food instructions, and any restrictions related to the product’s release design.

Sublingual medicines are placed under the tongue, while buccal medicines are placed against the inside of the cheek; both are absorbed through the mouth’s lining. Use them as directed rather than swallowing them immediately. These routes are not the same as ordinary oral swallowing.

Topical medicines are applied to a body surface, usually for local action. Apply them only to the labeled site and use the specified amount; topical products are not necessarily intended to produce whole-body effects. Transdermal products are applied to the skin to deliver medicine through it, often over time. Follow patch instructions for site, wear time, removal, and disposal, and do not assume a topical cream and a transdermal product have the same purpose.

Inhaled medicines are breathed into the respiratory tract. Device type and technique affect delivery, so follow product-specific priming, loading, inhalation, and cleaning directions. Nasal medicines are delivered into the nose as drops, a spray, or another specified form. Use the correct device and route; nasal products are not automatically interchangeable with products intended for inhalation into the lungs.

Ophthalmic products are applied to the eye, and otic products are applied to the ear. Confirm the labeled site and formulation. Eye preparations have requirements appropriate to that route; never substitute ear drops for eye drops unless specifically directed by an authorized professional.

Parenteral medicines are delivered by a specified injection or infusion route, including intravenous, intramuscular, or subcutaneous routes. Products may require reconstitution or dilution and must be prepared and administered exactly as labeled. Route-specific sterility and handling are important.

Rectal or vaginal medicines are inserted into the rectum or vagina, often as a suppository, cream, or other insert. Confirm the intended route, form, and instructions; a product designed for one site should not be assumed suitable for another.

Formulation and safe dispensing

Release characteristics

Immediate-release products release medicine without a deliberate release-modifying design. A delayed-release product is designed to release medicine later, while an extended-release product is designed to release it over a longer period. Do not crush, chew, split, or open these products unless the product-specific directions permit it, because altering the dosage form can affect safety or effectiveness.

Preparation and measurement

A powder for solution or suspension may need reconstitution. Use the specified diluent and amount, mix as directed, and provide the product’s storage and discard instructions.

For oral liquids, match the prescribed dose to the labeled concentration and use a suitable dosing device. Concentrations can differ between products, so do not rely on volume alone when verifying a dose.

Devices, sites, and verification

Inhalers, sprays, patches, and applicators are part of how the dosage form is delivered. Check that the device and route match the prescription, and give product-specific directions.

Verify the dosage form, strength, route, and directions against the prescription and the product’s approved labeling. Product labeling identifies dosage forms, strengths, routes, and administration instructions.