Dosage forms
Also known as: drug dosage forms, pharmaceutical dosage forms
A dosage form is the physical form in which a medication is manufactured and dispensed — tablet, capsule, solution, suspension, ointment, patch, injection, and so on. The dosage form determines how a drug is administered and how quickly it is absorbed.
A dosage form combines the active ingredient with inactive ingredients, or excipients, into a product a patient can actually take. The choice of form is not cosmetic: it controls the route of administration, the rate and extent of absorption, the stability of the drug, and how accurately a dose can be measured. Dosage forms are usually grouped as solid, liquid, semisolid, and gaseous or inhaled.
Solid forms include tablets, capsules, powders, lozenges or troches, and suppositories. Tablets may be chewable, sublingual, buccal, enteric-coated, or extended and delayed release. Liquid forms include solutions, in which the drug is fully dissolved; syrups, which are sweetened aqueous solutions; elixirs, which are hydroalcoholic and therefore inappropriate for some patients; suspensions, in which undissolved particles must be shaken before each dose; emulsions; tinctures; and injectable preparations. Semisolid forms include ointments, which are oil-based and occlusive, creams, which are oil-in-water and water-washable, plus gels, lotions, and pastes. Inhaled and transdermal products round out the list, including metered-dose inhalers, nebulizer solutions, and patches designed for slow systemic delivery.
Several practical rules follow from the form itself. Extended-release, delayed-release, and enteric-coated products must not be crushed or chewed, because doing so destroys the release mechanism and can deliver a dangerous bolus of drug. Suspensions need a shake-well auxiliary label, and reconstituted oral suspensions carry a beyond-use date that is shorter than the dry powder's expiration. Sublingual and buccal tablets bypass first-pass hepatic metabolism, giving a faster onset than a swallowed tablet. And the abbreviation on a prescription — tab, cap, susp, ung, supp — identifies the intended form, so a technician must match it exactly when selecting stock.
The PTCE tests dosage forms throughout the medications and order-entry domains. Be able to match a form to its route and onset, recognize which products cannot be crushed, apply the correct auxiliary labels, and read the dosage form abbreviations used in prescription sig codes.
Key takeaways
- A dosage form is the physical form of a medication and determines its route of administration and absorption profile.
- The main categories are solid, liquid, semisolid, and gaseous or inhaled preparations.
- Suspensions contain undissolved drug and must be shaken; solutions are homogeneous and do not.
- Extended-release, delayed-release, and enteric-coated products must never be crushed or chewed.
- Sublingual and buccal forms bypass first-pass metabolism, producing a faster onset than swallowed tablets.