Dosage Forms

Different Types of Drugs Available to Consumers

3 classifications based on how they are sold:

• Over-the-counter (OTC) drugs - commonly used and may be purchased without a prescription

• Legend drugs - require a prescription and are often noted as Rx

• Behind-the-counter (BTC) drugs - do not require a prescription, but are kept in the pharmacy and are limited by quantity or pharmacist approval

Dosage Forms

Dosage form: the means by which a drug is available for use or the vehicle by which the drug is delivered

• Not all drugs come in all forms and are determined primarily by which form makes the drug most effective

• Cost, ease of taking, and how quickly it needs to work is considered

Categories

Solids - tablets, capsules, lozenges, troches, implants

Liquids - syrups, elixirs, sprays, inhalants, aerosols, emulsions, suspensions, enemas

Semisolids - creams, lotions, ointments, gels, pastes, suppositories, powders, transdermal patches

Excipients (Additives)

Excipients are additives and may include:

• Fillers to increase the size of the medication (the drug may be so small it otherwise could not be handled)

• Preservatives to control microbial growth and extend shelf life

• Color to improve appearance

• Flavorings to improve taste

Compounding pharmacies may help pts that are allergic or have conditions where they cannot take readily available forms.

Solids

Can be contained in various packages and administered by almost all routes except parenterally (medication usually given by injection) that come in tablets/caplets, capsules, lozenges/troches, implants, and patches.

• Tablets/Caplets - come in variety of sizes, shapes, colors, thickness, and composition and usually contains a filler with no active ingredient (additives may be used to improve absorption and distribution)

  • Some tablets are scored, allowing them to be cut in half so half of the dosage can be given (even distribution of the active ingredient)

  • Enteric Coated - protects the drug through the acidic environment of the stomach or to delay release of the drug (extended release); never cut or crush an EC tab (if the protective covering is disrupted, it loses its protective qualities)

  • Chewable Tablets - convenient for children and people with difficulty swallowing

  • Orally Disintegrating Tablets - may be dissolved in the mouth without water

  • Caplets - smooth sided and easier to swallow; some mat be administered sublingually

• Capsules - composed of gelatin containers and may have hard or soft outer shells

  • Spansules - capsules that can be pulled apart with contents sprinkled onto soft food (do not crush or chew)

  • Gel Caps - soft capsules that cannot be opened and often hold medication in liquid form

• Lozenges/Troches - aimed at local action in the mouth or throat

  • Lozenges - similar to hard candy

  • Troches - type of tablet that is meant to dissolve in the mouth

• Implants - sterile dosage form that consist of drugs and rate-controlling additives intended for insertion into a body cavity or under the skin; often biosoluble (they degrade in the body over time)

• Transdermal Patches - material that holds a specific amount of medication to be released into the skin and absorbed into the bloodstream; easy to apply and eliminated the possibility of an upset stomach

  • Do not discard in trash w/o protecting the patch, fold over onto itself and place in pouch or baggie (wear gloves)

Liquids

Composed of various solutions, is very versatile (can be given through a variety of routes), and may come in syrups, elixirs, sprays, inhalants/aerosoles, emulsions, suspensions, and enemas.

• Syrups - sugar based solutions in which medication has been dissolved in them (improves taste) and is usually thicker than water

• Elixirs - contains dissolved medication in a water and alcohol base that is used as a solvent for med. to be placed into the solution; sweetener improves the taste of alcoholic mixture (same consistency as water)

• Suspensions - very small, solid particles suspended in the base solution used when the active ingredients would be unstable when dissolved in a solution but are stable when in a suspension

  • Follow manufacturer recommendation for mixing suspensions (vigorous shaking vs less vigorous)

  • Label with mixing instructions “shake well”

• Emulsions - mixture of water and oil bound together by an emulsifier that stabilizes and improves dispersion of the medication

• Sprays - composed of various bases, such as alcohol or water, in a pump-type dispenser

• Inhalants/Aerosoles - must be easily inhaled into the lungs with fine particles that delivers med. directly to the site of inflammation

  • Common devices include vaporizers and humidifiers; respiratory therapists use nebulizers to give breathing treatments to pts

  • Anesthetics - inhaled solutions administered by an anesthesiologist during surgery

  • Metered Dose Inhalers (MDIs) - dispense a specific amount of drug with each puff

  • Spacer - allows less med to be swallowed vs inhaled

• Enemas - delivered into the rectum to bypass the stomach

  • Retention - medication is retained for a desired amount of time before it is released

  • Evacuation - empties the bowel

Semisolids

Contain both liquids and solids usually intended for topical application that may come in creams, lotions, ointments. gels, pastes, suppositories, and powders.

• Creams - medication in a base that is part oil and part water; may have an emulsifier to keep parts combined

  • Massages easily into skin w/o residue and be used topically, vaginally, or rectally

• Lotions - thinner than creams because the base contains more water

• Ointments - medication in a glycol or oil base that repels moisture but leaves an oily residue

• Gels - medication in a viscous (thick) liquid that easily penetrates the skin with no residue; most water content

• Pastes - contain a smaller amount of liquid base than solids with absorption properties (absorbs skin secretions)

• Suppositories - rectal suppositories bypass the stomach (important if pt has nausea/vomiting); can be used rectally and vaginally and may act systematically or treat local conditions

• Powders - solids, but can be packages in some forms that allows them to be sprayed; one of the main ways to reduce amount of moisture