1. Dosage Forms and Routes of Administration
Chapter 5

2. Drug Classification and Dosage
Lesson 5.1
Drug Classification and Dosage
List dangerous abbreviations and explain why they are on the “Do Not Use” list.
Recognize the general classifications of medications and the related body systems.
Identify various dosage formulations and give examples of each.

3. Introduction
To become proficient, a technician must interpret prescribers’ orders correctly
Many doctors’ handwriting is referred to as “chicken scratch”; it is the responsibility of the pharmacy to interpret and clarify orders if necessary
Many abbreviations used in prescribing medication look very much alike
Because of the errors that can occur when interpreting handwriting, most pharmacies have gone to e-prescribing.
Technicians should be aware of “Do Not Use” abbreviations and always ask when in doubt.

4. Where Did Pharmacy Abbreviations Originate?
Pharmacy and medical terminology comes from the Latin and Greek languages
Latin and Greek serve as universal languages in medicine
Because pharmacy began in Europe, most abbreviations have their origins in a foreign language
Sometimes knowing the origin of a word or an abbreviation can help you remember it.
For example, the D and S, used in abbreviations such as OD and OS, come from the Latin words dexter (right) and sinister (left). The right side was once associated with skill, as reflected in the word dexterous. In contrast, the left side was associated with evil, such as in the word sinister.

5. Interpreting Prescribers’ Orders
It is very important for the pharmacy staff to interpret prescribers’ orders correctly
When writing out the various abbreviations, be sure to write as neatly as possible because other technicians and pharmacists will be reading your handwriting
Technicians must learn all the dosage forms and abbreviations to decipher prescribers’ orders
Medication errors can occur very easily during the process of transferring a prescription order into the data entry. Knowing the abbreviations for dosage forms and routes can help technicians understand prescribers’ orders and prevent mistakes in many cases.

6. “Do Not Use” List
Drug errors that have occurred as a result of the misinterpretation of medication orders led to the creation of the “Do Not Use” list
The list outlines the most common misread abbreviations
These abbreviations should be avoided
See Table 5-1 (p. 103) for the official “Do Not Use” list established by the Joint Commission (TJC).
TJC is an accrediting organization for hospital systems.
Other lists, such as tall man lettering and look-a-like, sound-a-like drugs are also used to make health care workers aware of potential errors in labels.
Take the time to look at these lists and be aware of special storage or notations, such as “stop signs,” to identify them on the shelf.

7. Dosing Instructions Dosing times are abbreviated on prescriptions
Many pharmacy computers are programmed to accept these abbreviations
See Table 5-2 (pp ) for a list of error-prone abbreviations, symbols, and dose designations.
These abbreviations are included in the “Do Not Use” list and should never be used. For example, look at QD, QOD, and Q.D.
Another point to remember is never to use trailing zeros.

8. Classification of Medications
Drugs can be classified into different groups based on:
Pharmacology
Intent of use
Route of administration
Mechanism of action
Body system affected
Although many medications are used for reasons other than their intended purpose, it is important to know the body system a medication is intended to affect.

9. Different Types of Drugs Available to Consumers
Three classifications describe the drugs available to consumers:
Over-the-counter (OTC) drugs
Legend drugs
Behind-the-counter (BTC) drugs
OTC drugs are commonly used and may be purchased without a prescription.
Legend drugs require a prescription before they can be purchased and are often denoted as Rx.
BTC drugs do not require a prescription but are kept in the pharmacy; their sales are limited by quantity or may require a pharmacist’s approval.

10. Dosage Forms
Dosage form: The means by which a drug is available for use
For example, the form may be a tablet, but there are many types of tablets
Tablets can be scored or unscored and coated or uncoated
The dosage form is determined primarily by which form makes the drug most effective
Manufacturers prepare certain medications with the ability to release the active ingredient over an extended period
Most scored tablets can be split without altering the medicine’s effectiveness.

11. Unscored and Scored Tablets
Figure 5-1 shows an unscored tablet (A) and a scored tablet (B).
What are the benefits and drawbacks of scored tablets? (It’s possible to save money by buying a higher-dose tablet and using a pill splitter to cut it into smaller-dose tablets. This is an option if a physician recommends a smaller dose midway through a prescription. Some health maintenance organizations [HMOs] even endorse or require pill splitting, although studies have shown that not all patients can safely and accurately split their medicines.)

12. Dosage Forms Three major categories of dosage forms: Solids Liquids
Semisolids
Many of the top-selling drugs are available in several different dosage forms.

13. Solids
Can be contained in various packages and administered by almost all routes except parenterally
Most tablets contain fillers (inert substances that have no active ingredient), sugar coatings, and certain additives
The following inert ingredients might have one or more purposes:
Fillers may be used to increase volume so that the pill is easy to handle.
Binders may be used to hold the tablet together.
Disintegrants may be used to help the tablet dissolve within the 15 to 30 minutes required by the U.S. Pharmacopeia (USP).

14. Tablets Made to be administered sublingually (SL) or vaginally
Some may be scored, which allows the dosage to be cut in half
May be enteric coated to protect the drug through the acidic environment of the stomach or to delay release of the drug
Chewable tablets are convenient for children and people who have difficulty swallowing
Extended-release types are made to control the amount of drug distributed over a set time
What does sublingual mean? (Under the tongue)
You should never cut or crush an enteric-coated tablet. An enteric coating is a protective covering, and if it is disrupted, it will lose its protective qualities. For a complete list of “Do Not Crush” drugs, check the website of the Institute for Safe Medication Practices (ISMP) at
Always be careful and use the National Drug Code (NDC) number for identification when choosing a medication to ensure that the correct dosage form is chosen; for example, SA (sustained action), SR (sustained release), and CD (controlled diffusion).

15. Types of Tablets
Figure 5-2 shows three different types of tablets.

16. Tablets and Caplets
The most common type of tablet contains some type of filler
Fillers are composed of inert substances (no active ingredient) that fill space or cover the tablet (sugar coatings)
Coating improves the taste and covers unpleasant odors
Caplets are smooth sided and easier to swallow
Many medications have extended-release forms and regular forms
Why would a chewable tablet be needed? (Pediatric and geriatric patients may do better with a chewable tablet. Coatings and flavorings improve patient compliance.)
Orally disintegrating tablets (ODTs), which do not need to be taken with water, are made to dissolve rapidly to get medication into the bloodstream as quickly as possible. Can you see a need for this dosage form? (Answers will vary.)

17. Capsules Can have either a hard or soft outer shell
Hard capsules: Composed of sugar, gelatin, and water
Pulvule: A type of capsule that is shaped differently for identification purposes
Spansule: Capsule that can be pulled apart to sprinkle the medication onto food for children
Soft-gelatin capsules (gel caps): Cannot be pulled apart; often hold medications in liquid form
Capsules can even have tablets inside them.
Spansules are designed to be pulled apart and release their contents.
Capsules are available in many different sizes.

18. Types of Capsules Figure 5-4, A shows normal-release capsules.
Figure 5-4, B shows extended-release capsules.

19. Lozenges/Troches and Biomaterials
Troches: A type of tablet that is meant to dissolve in the mouth
Flat, larger than normal-sized tablets; have a chalky consistency
Biomaterials: Polymers (long chains of hydrocarbons) that combine with or encapsulate a drug
Can be capsules, tablets, or implants
Drug can be activated by pH or solubility and released over a period of 12 hours to several years
Troche is pronounced “TRO-key” with a hard k because it’s a Greek word; some people pronounce it as “trosh” with a long o.
Clotrimazole, an antifungal, is one of the more common troches.
Biomaterials help maintain a steady release of the drug into the body.

20. Implants
A special type of capsule can be implanted under the skin and left in place for up to 5 years
Contraceptives containing progestin are implanted
Medication is released in a stair-step method
Progestin birth control implants are effective within 24 hours of insertion.

21. Transdermal Patches
Transdermal patches: Solid pieces of material that hold a specific amount of medication to be released into the skin over time
Easily administered and eliminate the possibility of an upset stomach
Uses
For angina: Nitroglycerin
For chronic pain: Duragesic
For motion sickness: Scopolamine
What other types of patches are popular today? (Nicotine and contraceptive patches are popular [and heavily advertised]).

22. Liquids Composed of various solutions
Can be administered by all routes
Syrups: Sugar-based solutions in which medication has been dissolved in them; they improve the taste of the drug
Tend to be thicker than water
Why is liquid medication often a good option for young children? (Very young children or those with developmental delays might not have enough control of the swallowing reflex to handle solid medication. It is easy to adjust the dose of a liquid for a child’s weight.)
Sugar-based liquids would not be appropriate for what type of patient? (Diabetic patients)

23. Elixirs and Sprays
Elixirs: Contain dissolved medication in either an alcohol base or a (hydroalcoholic) base
Alcohol usually covers up the bad taste of the drug
Elixirs have the same consistency as water
Sprays: Composed of various bases, such as alcohol or water, in a pump-type dispenser
Nitroglycerin translingual spray is used under the tongue for relief of anginal pain
Dimetapp is an example of an elixir.
A spray can be used to get medication into the system quickly because no barriers, such as coatings or flavorings, need to dissolve.

24. Inhalants and Aerosols
Inhalants: Available in a variety of forms, but all must be easily inhaled into the lungs
Common devices available OTC are vaporizers and humidifiers
Respiratory therapists use nebulizers to give breathing treatments to hospital patients
Patients can also be taught to use nebulizers at home
Anesthetics: Inhaled solutions administered by an anesthesiologist during surgery
Metered dose inhalers (MDIs): Dispense a specific amount of drug with each puff
How are orally inhaled agents often wasted? (If the patient does not use the device correctly, he or she will swallow most of the medication instead of inhaling it into the lungs.)
Many pharmacies now provide the FluMist nasal flu vaccine.
FluMist contains a portion of the live virus, so it should not be administered to people who have weaker immune systems, such as small children or older adults.

25. Emulsions and Suspensions
Emulsion: A mixture of water and oil bound together by an emulsifier
Many different types of emulsifiers are used
Suspension: A liquid in which very small, solid particles suspended in the base solution
Can be used orally by children and older adults
Should have a “Shake well” sticker and an expiration date
Antacids are common OTC emulsions.
Homogenized milk is a stable emulsion; the tiny fat particles are bound to water by emulsifying proteins.
Remember to mix bulk doses of suspensions well before dispensing or repackaging.

26. Enemas Enemas might be administered for one of two reasons:
Retention or evacuation
They can be used to deliver medication to the body, bypassing the stomach for absorption
Most common use is to evacuate the lower intestine to prepare for surgeries or for women in labor
Enemas are provided in a water base so that they take effect more quickly, usually in less than 10 minutes.

27. Semisolids Contain both liquids and solids
Are meant for topical application
Creams: Medication in a base that is part oil and part water; for topical use
Lotions: Thinner than creams because the base contains more water
Based on their water or oil content, several types of semisolids will be thicker or thinner in consistency.
Some semisolid preparations are made to dissolve into the skin, and some are intended to create a barrier and remain on the skin’s surface.

28. Semisolids Ointments: Medication in a glycol or oil base
Cover the skin’s surface and keep out moisture
Gels: Medication in a viscous (thick) liquid that easily penetrates the skin
Pastes: Contain a smaller amount of liquid base than solids; able to absorb skin secretions, unlike other topical agents
Ointments are oil based and designed to stay on the top of the skin (for example, Desitin for diaper rash).
Would Desitin work well for diaper rash if it dissolved? (No, because the urine would still come in contact with the surface of the skin and irritate it. A barrier needs to be created to prevent this from happening.)
Pastes are very thick.

29. Suppositories and Powders
Suppositories can be used both rectally and vaginally
Rectal suppositories bypass the stomach, which is important if the patient has nausea and vomiting
Vaginal suppositories are used mainly to treat vaginal infections
Powders are solids, yet they can be packaged in some forms that allow them to be sprayed, similar to liquid dosage forms
One of the main uses is to reduce the amount of moisture in an area
There are also urethral suppositories.
Suppositories are solid while dry at room temperature, but they melt, soften, or dissolve in the body.
Compounding pharmacies use different bases for suppositories, depending on the desired speed of effect.
Powders are absorbed quickly if taken by mouth. If they are semisolid, they don’t have a water component, and this reduces moisture in areas such as those with a fungal infection, which thrives in a wet environment.
Powders can be spread over a wide area.

30. Routes of Administration, and Drug Storage and Use
Lesson 5.2
Routes of Administration, and Drug Storage and Use
Identify various routes of administration and give examples of each.
Explain the difference between pharmacokinetics and pharmacodynamics.
List and explain the absorption, distribution, metabolism, elimination, and bioavailability of drugs in the body.
Define first-pass metabolism and explain why it is important in drug delivery.
Define half-life and describe factors that influence it.

31. Routes of Administration, and Drug Storage and Use
Lesson 5.2
Routes of Administration, and Drug Storage and Use
Define the bioequivalence of drugs and its relationship to the Orange Book.
Describe why excipients (additives) are necessary in the production of medications.
List three different common drugs and their storage requirements.
List the segments that make up medical terms and provide examples of each.
Recognize and interpret common abbreviations as they apply to dosage forms and routes of administration.

32. Routes of Administration
Oral (by mouth) medications are very convenient, do not need to be measured, are less expensive, systemic, and safe
Do not work as quickly as parenterals
Some drugs cannot be taken orally because they are not as effective
How long does it take for an oral medication to become active? (Between 30 minutes and 1 hour)
What is the abbreviation for oral administration? (PO, the abbreviation for the Latin term per os, or by mouth.)
When typing a prescription’s directions, use the verb TAKE.

33. Sublingual and Buccal Drugs
Nitroglycerin (NTG), which treats anginal attacks, is the most commonly used sublingual tablet
Buccal agents are placed between the gum and cheek, where the medication penetrates the mouth lining and then enters the bloodstream
Refer to Figure 5-8 (p. 115) to see the placement of sublingual and buccal medications.
Buccal means cheek, but it is sometimes used to refer to the tongue (as in a buccal smear, in which cells are swabbed from the tongue for lab testing).
Sublingual and buccal medications have a very rapid onset of action (work quickly), which is why NTG is provided in this form.

34. Rectal Agents
Rectal (PR) agents are used for a person who is vomiting and cannot take oral medications
To reduce inflammation, either ointments or creams can be used in addition to suppositories
Rectal agents usually work on a specific site and not systemically
They are uncomfortable and the actual amount of drug absorbed is hard to predict
For nausea and vomiting, rectal forms of medication can work systemically by entering the lymph nodes of the rectal area, which are the highways in the body.
For hemorrhoids, rectal agents can be used to treat the condition locally.
Use INSERT for this dosage form.

35. Topical Drugs Effects range from systemic to localized (for rashes)
These agents can fight skin infections, inflammation, and block UV rays of the sun
Work at the site of action and systemically
Advantage: Easy application
Disadvantage: May cause a reaction
Patient compliance is good for this form because application is easy.
Many topical (TOP) drugs are designed to enter the bloodstream and work systemically, NTG or birth control patches. They can be left in place for hours or days.
Note: Always remember to discard these patches properly because some active drug may remain in the patch.
Use APPLY for the verb when typing patient directions.

36. Parenteral: Intravenous, Intravenous Piggyback, Intramuscular, Subcutaneous Drugs
The term parenteral is Greek in origin and means “side of intestine” or “outside of intestine”
The most common parenteral medications are given IV, IM, or SC
Very-small-gauge needles are used; the length depends on the injection site
Parenteral drugs work within a few minutes
This is important for emergency situations, for those who are combative, or for those who are unable to swallow
Disadvantage: Increased risk of infection
What do the abbreviations IV, IM, and SC mean? (Intravenous, intramuscular, and subcutaneous)
What is another abbreviation for subcutaneous? (SQ, although this is on the ISMP’s “Do Not Use ” list, which recommends SUBCUT instead)
Parenterals can also be administered intradermally (abbreviated ID). ID injections are administered just under the skin’s surface.
Typical uses of ID injections include skin testing for tuberculosis and allergies.
Another disadvantage is the pain of an IV and the need for a professional to place it.

37. Parenteral: Intravenous, Intravenous Piggyback, Intramuscular, Subcutaneous Drugs
Injections are more expensive and require preparation and administration by trained personnel
Disadvantage: Once a drug is injected, there is little time to alter its course if an allergic reaction takes place or too much drug is given
In 30 states, pharmacists can be authorized to administer intramuscular and subcutaneous vaccines as prescribed by physicians.
Technicians who work in community pharmacies that offer vaccinations should be prepared to help respond to medical emergencies, such as allergic reactions.
Preparation of IV dosage forms requires aseptic technique to eliminate any bacteria because this form of a drug bypasses the gastrointestinal (GI) system and goes directly into the bloodstream.

38. Drugs for the Eye, Ear, and Nose
Eye (ophthalmic) solutions are often used to treat ear (otic) conditions, but ear solutions cannot be used to treat eye conditions because the eye is sterile
Otic preparations are not necessarily sterile because they treat the ear canal and do not penetrate a sterile environment
Be careful with abbreviations for the eye and ear. OU, OS, and OD are for EYES. (OTIC: Hint).
AU, AS, AD are for the EAR. (AURAL: Hint)
Eye medications must be sterile; ear medications are not necessarily sterile.

39. Drugs for the Eye, Ear, and Nose
All ophthalmics must be kept sterile
Different types of agents are available for the eye, ear, and nose, including ointments, solutions, and suspensions
These dosage forms work on the specific site
Most ear treatments are done to clear up infections or clean out earwax buildup
Most nose (nasal) sprays are used to treat colds and allergies
Eye treatments are for infections, inflammation, and glaucoma
Patients should always be taught the correct way to use and administer these drugs. For example, ear preparations should never be microwaved, but rather warmed to room temperature.
The latest generation of nasal sprays includes antihistamines, which can treat allergic reactions that result in nasal congestion, at the site of the reaction.

40. Inhalants Inhalants (INH) are used to treat lung diseases
Dosage forms are limited but very effective if used properly
Metered dose inhalers (MDIs) are used for asthma, bronchitis, or emphysema
Corticosteroids are also available in MDIs for chronic conditions
Two types: Propellant and dry powder
Most aerosols come in handheld units and are very convenient
Disadvantage: Little if any of the drug is able to get into the lungs
Inhalants are designed to go directly into the lungs. Patient compliance and the method of administration are sources of problems. Sprays often are not administered close enough to the mouth and thus are wasted. In addition, an MDI has only a certain number of sprays.
Use SPRAY as the verb for the patient directions.
Ensuring that the patient understands how to administer inhalants is extremely important. As a technician, be sure to refer the patient to a pharmacist for instructions and always include the package insert (instructions) when dispensing.

41. Injectables
Long-acting parenteral drugs are available that can be used in place of daily dosing
They should never be given intravenously
For some patients, such as mentally ill (schizophrenic) individuals, this is a way to ensure compliance.
Haldol LA is an injectable antipsychotic that can be given and lasts for 28 days.
Many of these patients are homeless and do not take their medications correctly.

42. Miscellaneous Routes
Miscellaneous routes include vaginal or urethral dosage forms: Suppositories, ointments, foams, and gels
They are used to treat infections and inflammation; vaginal foams are used as a contraceptive
Advantage: They bypass a systemic effect and affect a specific site
Disadvantage: They are not easily applied and are uncomfortable
Rings are another form of medication available as a birth control method.

43. Other Considerations: Form and Function
Dosage forms are created based on the results from many clinical trials that delve into the pharmacokinetics of the medication or the function of the drug in experiments
Pharmacokinetics refers to the way the body handles a drug. Each dosage form acts differently, and this is a consideration when deciding on the proper form to use.

44. Pharmacokinetics vs. Pharmacodynamics
Pharmacokinetics: Encompasses the many different components of the actions of the body on a drug
Levels of the drug throughout the blood and tissues
Absorption of the drug throughout the body
Overall distribution
Reaction of the drugs with other drugs
Patient compliance
Life of the drug (bioavailability, half-life, bioequivalence, and elimination)
Pharmacodynamics: The effects of the drug on the body
Drugs go through phases as they enter the body. Depending on the dosage form used, the life span of the drug is different.
Some drugs are eliminated quicker than others, and dosing can depend on organ function or the presence of disease.

45. Absorption
Medications are made to get through natural body barriers, such as the skin, stomach, intestines, blood-brain barrier, and other membranous tissues
How well the drug passes through these barriers (absorption) is the one factor that determines its ultimate effectiveness
Drugs are absorbed first; dosage forms such as inhalants and injectables are quicker than tablets or capsules.
The blood-brain barrier (BBB) is a natural phenomenon in which capillaries around the brain prevent some substances from being absorbed by brain tissue.
In this way, the brain is protected from many common infections.

46. Distribution
After a medication is absorbed, it is distributed throughout the body via the bloodstream into tissues, membranes and, ultimately, organs
Distribution of a drug is not necessarily equal throughout the body
Most drugs bind to blood proteins to some degree
Drugs such as warfarin (a “blood thinner,” or anticoagulant) and phenytoin (an anticonvulsant) are examples of types of drugs in which alterations in protein binding can become clinically important to the amount of drug available for distribution and therapeutic effect.

47. Metabolism Most metabolism takes place in the liver.
Metabolism changes the chemical structure of the original drug
Different influences can alter metabolism: Age, gender, genetics, diet, and other chemicals digested
Metabolism includes all the changes a substance is subjected to in the body.

48. First-Pass Effect
For some drugs, the dose travels to the liver, and part of it is metabolized before the drug has a chance to be distributed throughout the body
This first-pass effect lowers a drug’s bioavailability
First-pass drugs are given in larger doses
Intravenous agents bypass the first-pass phenomenon because they enter the bloodstream directly.
Other drugs do not undergo any change at all and are excreted from the body in the same form in which they were introduced.

49. Elimination Elimination is the last phase of a drug’s life in the body
Drugs can be excreted in many ways: Via the kidneys, feces, exhalation, sweat glands, and breast milk
Urination and bowel movements are the most common methods of excretion
Because excretion can also occur through breast milk, some drugs are labeled as Pregnancy Category X (not approved for pregnant or nursing mothers).
If a person has a disease of the kidneys, might he or she need to have different dosing? (Answers will vary.)

50. Bioavailability
The rate at which a drug makes it to its destination and becomes available to the site of action for which it is intended (bioavailability)
Different drugs clear in different ways and at different times
Many drugs travel to the liver before they have a chance to be absorbed into the whole system (first-pass effect)
Orally administered drugs both affect the liver and are affected by the liver.
What are ways to avoid the first-pass effect? (Drugs administered by other routes, such as sublingual, buccal, and parenteral routes, avoid the destructive effects of gastric fluids.)

51. Half-Life
The amount of time it takes the body to break down and excrete one half of a drug
An important factor in the creation of drugs because it tells the manufacturer how long it takes the body to rid itself of the drug
Some drugs have extremely short lives, which means they must be taken more often. Do you think an LA or XL dosage form capsule has a longer or shorter half-life? (Longer)
Some drugs can stay in the system for weeks.

52. Bioequivalence
The comparison between drugs either from different manufacturers or in the same company but from different batches of a drug
Generic drug manufacturers strive to achieve bioequivalence to compete with brand name manufacturers
A bioequivalence variation of 20% between generic and brand name drugs is legal, but actual variance averages 3.5%.
Drugs given in very small amounts, such as digoxin for heart failure, are less reliably interchangeable between brand name and generic because of the small margin of safety between a therapeutic dose and a harmful dose.
The FDA publishes bioequivalencies in the Orange Book.

53. Use of Excipients
All medications are prepared with additives (excipients)
Coloring, flavorings, fillers, and preservatives
Some patients may be allergic or intolerant to these additives
Other types of excipients: Increase the dispersion of a drug once it reaches the intestines, or release the medication over a longer period
The recipe for the same USP drug might vary between manufacturers because of different additives.
For example, some patients may be allergic to the dyes used in some medications; this would be a good example of the need to compound the drug for that specific patient.

54. Packaging and Storage Requirements
All types of dosage forms must be approved by the FDA
Medications are packaged according to manufacturers’ specifications to ensure the effectiveness and shelf life of the drug
All medications have a package insert that describes the storage and stability of the drug
The package insert should be reviewed when the drug is dispensed.
Refer to Table 5-9 (p. 125) to see examples of storage requirements.

55. Medical Terminology
Medical terms have their origins in Greek and Latin
There are four segments, or word parts:
Prefix: Before combing form (peri-)
Suffix: After combining form (-itis)
Root word (heart)
Combining form (cardio)
See Terms and Abbreviations (p. 101).
See Box 5-2 (p. 126) for the word parts used in medical terminology.
Review Table 5-10 (p. 125) to see additional abbreviations.

56. Questions?