Pharmacist's Guide

Table of Contents

• Drug List and Classification
• Drug Prescription for Disease
• Drug Over-the-Counter (OTC)
• Drug Prescription Abbreviations and Meanings
• Drug Schedules to the Rules
• Drug Mechanism of Action (MOA)
• Drug Glossary and Definition
• Medical Abbreviations
• Pharmacist Role
• Dosage Forms

DRUG DELIVERY SYSTEMS

Drug delivery systems are physical carriers used to deliver medications to site-specific areas. They include transdermal, ocular, and intrauterine systems. Transdermal drug delivery systems support the passage of drug substances from the surface of the skin, through its various layers, and into the systemic circulation. These systems are sophisticated skin patches containing a drug formulation within a reservoir for the controlled delivery of drug. Ocular drug delivery systems consist of drug-impregnated membranes that, when placed in the lower conjunctival sac, release medication over an extended period. Intrauterine drug delivery systems consist of a drugcontaining intrauterine device that releases medication over an extended period after insertion into the uterus.

DOSAGE FORMS

AEROSOLS

Pharmaceutical aerosols are products packaged under pressure that contain therapeutically active ingredients that are released as a fine mist, spray, or foam on actuation of the valve assembly. Some aerosol emissions are intended to be inhaled deep into the lungs (inhalation aerosol), whereas others are intended for topical application to the skin or to mucous membranes. Aerosols with metered valve assemblies permit a specific quantity of emission for dosage regulation.

AROMATIC WATERS

Aromatic waters are clear, saturated solutions of volatile oils or other aromatic substances in water. They are used orally, topically, or pharmaceutically for the characteristics of the aromatic material they contain.

BOLUSES

Boluses are large elongated tablets intended for administration to animals.

CAPSULES

Capsules are solid dosage forms in which one or more medicinal and/or inert substances are enclosed within small shells of gelatin. Capsule shells are produced in varying sizes, shapes, color, and hardness. Hard-shell capsules, which have two telescoping parts, are used in the manufacture of most commercial capsule products and in the extemporaneous filling of prescriptions. They are filled with powder mixtures or granules. Soft-shell gelatin capsules are formed, filled, and sealed in a continuous process by specialized large-scale equipment. They may be filled with powders, semisolids, or liquids. Capsules contain a specific quantity of fill, with the capsule size selected to accommodate that quantity. In addition to their medication content, capsules usually contain inert substances, such as fillers. When swallowed, the gelatin capsule shell is dissolved by gastrointestinal fluids, releasing the contents. Delayed-release capsules are prepared in such a manner as to resist the release of the contents until the capsules have passed through the stomach and into the intestines. Extended-release capsules are prepared in such a manner as to release the medication from the capsules over an extended period following ingestion.

CREAMS

Creams are semisolid preparations containing one or more drug substances dissolved or dispersed in a suitable base. Many creams are either oil-in-water emulsions or aqueous microcrystalline dispersions in a water-washable base. Compared to ointments, creams are easier to spread and remove. Creams are used for administering drugs to the skin and, to a lesser extent, to mucous membranes.

ELIXIRS

Elixirs are sweetened, flavored, hydroalcoholic solutions intended for oral administration. They may be medicated or nonmedicated. Compared to syrups, elixirs are usually less sweet and less viscous because they contain a lesser amount of sugar. Because of their hydroalcoholic character, elixirs are better able than are syrups to maintain both water-soluble and alcohol-soluble components in solution.

EMULSIONS

An emulsion is a type of dispersal system in which one liquid is dispersed throughout another liquid in the form of fine droplets. The two liquids, generally an oil and water, are immiscible and constitute two phases that would separate into layers without the presence of a third agent, an emulsifier or emulsifying agent. The latter facilitates the emulsification process and provides physical stability to the system. If oil is the internal phase, then the emulsion is termed an oil-in-water, or o/w, emulsion. If water is the internal phase, then the emulsion is termed a water-in-oil, or w/o, emulsion. The type of emulsion produced is largely determined by the emulsifying agent, with hydrophilic agents generally producing oil-in-water emulsions and lipophilic agents generally producing water-in-oil emulsions. Emulsifying agents may have both hydrophilic and lipophilic characteristics, hence the term hydrophilic-lipophilic balance (HLB). Depending on their formulation, emulsions may be administered orally, topically, or by intravenous injection.

EXTRACTS

Extracts are concentrated preparations of vegetable or animal drugs prepared by extracting the constituents from the natural source and drying the extractive to the desired pilular or powdered form.

FLUID EXTRACTS

Fluid extracts are liquid extractives of vegetable drugs generally prepared such that 1 mL represents the active constituents from 1 g of the vegetable drug.

GELS

Gels are semisolid systems consisting of either suspensions of small inorganic particles or large organic molecules interpenetrated by a liquid.

IMPLANTS OR PELLETS

Implants or pellets are small, sterile, solid dosage forms containing a concentrated drug for subcutaneous implantation in the body where they continuously release their medication over prolonged periods.

INHALATIONS

Inhalations are finely powdered drug substances, solutions, or suspensions of drug substances administered by the nasal or oral respiratory route for local or systemic effects. Special devices are used to facilitate their administration.

INJECTIONS

Injections are sterile preparations intended for parenteral administration by needle or pressure syringe. Drugs may be injected into most any vessel or tissue of the body, but the most common routes are intravenous (IV), intramuscular (IM), and subcutaneous (SC). Injections may be solutions or suspensions of a drug substance in an aqueous or nonaqueous vehicle. They may be small-volume injections, packaged in ampules for single-dose administration, or vials for multiple-dose injections. Large-volume parenterals, containing 100 mL to 1 L of fluid, are intended for the slow intravenous administration (or infusion) of medications and/or nutrients in the institutional or home care setting.

IRRIGATIONS

Irrigations are sterile solutions intended to bathe or flush open wounds or body cavities. They are not intended for injection.

LINIMENTS

Liniments are alcoholic or oleaginous solutions, suspensions, or emulsions of medicinal agents intended for external application to the skin, generally by rubbing.

LOTIONS

Lotions are liquid preparations intended for external application to the skin. They are generally suspensions or emulsions of dispersed solid or liquid materials in an aqueous vehicle. Their fluidity allows rapid and uniform application over a wide skin surface. Lotions are intended to soften the skin and leave a thin coat of their components on the skin’s surface as they dry.

LOZENGES

Lozenges are solid preparations containing one or more medicinal agents in a flavored, sweetened base intended to dissolve or disintegrate slowly in the mouth, releasing medication generally for localized effects.

MAGMAS

Magmas are pharmaceutical suspensions of fine particles that, because of a high degree of physical attraction to the aqueous vehicle, form a gelatinous mixture. This characteristic maintains the uniformity and stability of the suspension. Magmas are administered orally.

OINTMENTS

Ointments are semisolid preparations intended for topical application to the skin, eye, ear, or various mucous membranes. With some exceptions, ointments are applied for their local effects on the tissue membrane rather than for systemic effects. Ophthalmic ointments are sterile preparations intended for application to the eye. Nonmedicated ointments serve as vehicles, or as ointment bases, in the preparation of medicated ointments. Because ointments are semisolid preparations, they are prepared and dispensed on a weight basis.

PASTES

Pastes are semisolid dosage forms that contain one or more drug substances intended for topical application to the skin. Generally, pastes contain a higher proportion of solid materials than do ointments and thus are more stiff, less greasy, and more absorptive of serous secretions.

PLASTERS

Plasters are solid or semisolid adhesive masses spread across a suitable backing material and intended for external application to a part of the body for protection or for the medicinal benefit of added agents.

POWDERS

Powders are dry mixtures of finely divided medicinal and nonmedicinal agents intended for internal or external use. Powders may be dispensed in bulk form, or they may be divided into single-dosage units and packaged in folded papers or unit-of-use envelopes.

PREMIXES

Premixes are mixtures of one or more drug substances with suitable vehicles intended for admixture to animal feedstuffs before administration. They are generally in powdered, pelletized, or granulated form.

SOLUTIONS

Solutions are liquid preparations that contain one or more chemical substances (solutes) dissolved in a solvent or mixture of solvents. The most common solvent used in pharmaceuticals is water; however, alcohol, glycerin, and propylene glycol also are widely used as solvents or cosolvents. Depending on their purpose, solutions are formulated and labeled for use by various routes, including oral, topical, ophthalmic, otic, nasal, rectal, urethral, and parenteral. The concentration of active ingredients in solutions varies widely depending on the nature of the therapeutic agent and its intended use. The concentration of a given solution may be expressed in molar strength, milliequivalent strength, percentage strength, ratio strength, milligrams per milliliter, or another expression describing the amount of active ingredient per unit of volume.

SPIRITS

Spirits are alcoholic or hydroalcoholic solutions of volatile substances. Depending on their contents, some spirits are used orally for medicinal purposes and others as flavoring agents.

SUPPOSITORIES

Suppositories are solid dosage forms intended for insertion into body orifices. They are used rectally, vaginally, and, occasionally, urethrally. Suppositories are of various weights, sizes, and shapes, depending on their intended use. Various types of suppository bases are used as vehicles for the medication, including cocoa butter (theobroma oil), glycerinated gelatin, polyethylene glycols, hydrogenated vegetable oils, and fatty acid esters of polyethylene glycol. Depending on the base used, the suppository either softens, melts, or dissolves after insertion, releasing its medication for the intended local action or for absorption and systemic effects.

SUSPENSIONS

Suspensions are preparations containing finely divided, undissolved drug particles dispersed throughout a liquid vehicle. Because the drug particles are not dissolved, suspensions assume a degree of opacity depending on the concentration and size of the suspended particles. Because particles tend to settle when leftstanding, suspensions should be shaken to redistribute any settled particles before use to ensure uniform dosing. Depending on their formulation, suspensions are administered orally, by intramuscular injection, and topically to the eye.

SYRUPS

Syrups are concentrated aqueous solutions of a sugar or sugar substitute. Syrups may be medicated or nonmedicated. Nonmedicated syrups are used as vehicles for medicinal substances to be added later, either in the extemporaneous compounding of prescriptions or in the preparation of a formula for a medicated syrup. In addition to the sugar or sweetener, syrups also contain flavoring agents, colorants, cosolvents, and antimicrobial preservatives to prevent microbial growth. Syrups are administered orally for the therapeutic value of the medicinal agent(s).

TABLETS

Tablets are solid dosage forms containing one or more medicinal substances. Most tablets also contain added pharmaceutical ingredients, as diluents, disintegrants, colorants, binders, solubilizers, and coatings. Tablets may be coated for appearance, for stability, to mask the taste of the medication, or to provide controlled drug release. Most tablets are manufactured on an industrial scale by compression, using highly sophisticated machinery. Punches and dies of various shapes and sizes enable the preparation of a wide variety of tablets of distinctive shapes, sizes, and surface markings. Most tablets are intended to be swallowed whole. However, some are prepared to be chewable, others to be dissolved in the mouth (buccal tablets) or under the tongue (sublingual tablets), and still others to be dissolved in water before taking (effervescent tablets). Tablets are formulated to binders, solubilizers, and coatings. Tablets may be coated for appearance, for stability, to mask the taste of the medication, or to provide controlled drug release. Most tablets are manufactured on an industrial scale by compression, using highly sophisticated machinery. Punches and dies of various shapes and sizes enable the preparation of a wide variety of tablets of distinctive shapes, sizes, and surface markings. Most tablets are intended to be swallowed whole. However, some are prepared to be chewable, others to be dissolved in the mouth (buccal tablets) or under the tongue (sublingual tablets), and still others to be dissolved in water before taking (effervescent tablets). Tablets are formulated to contain a specific quantity of medication. To enable flexibility in dosing, manufacturers commonly make available various tablet strengths of a given medication. Some tablets are scored, or grooved, to permit breaking into portions that the patient can take.

TINCTURES

Tinctures are alcoholic or hydroalcoholic solutions of either pure chemical substances or of plant extractives. Most chemical tinctures are applied topically (e.g., iodine tincture). Plant extractives are used for their content of active pharmacologic agents.