Medications Study Guide for the PTCB Exam

General Information

Like in any other profession, knowing and using the appropriate vocabulary is an integral part of succeeding as a pharmacy technician. Being familiar with common pharmaceutical names and spellings will make it easier to understand patients and communicate with other healthcare professionals. In the pharmacy setting, it is crucial to be exact with names and spelling, as two medications may have very similar names but be used for vastly different purposes.

Approximately \(35%\) of the current Pharmacy Technician Certification Board (PCTB) exam will be related to medications and their names and uses, which accounts for an additional \(5%\) of the exam compared to the \(2020\) addition.

Medication Names and Classifications

Typically, medications are known by both their brand and generic names. Healthcare professionals and patients may use them interchangeably, making it imperative to know both names for each medication to establish effective communication.

Generic Names

Generic drugs are typically lower-cost versions of brand-name drugs. A medication is produced under its brand name only while under patent (usually for around \(20\) years), as the pharmaceutical company that created the drug has sole rights to it. After that, other pharmaceutical companies can manufacture it under the generic name, which may also be known as the chemical name.

Brand Names

Brand names are typically shorter than generic names, and drug manufacturers often use brand names to advertise new medications. It is essential to note that a single generic drug may have multiple brand names, depending on the formulation and manufacturer. For example, zolpidem is available under the brand names Ambien®, Edluar®, Intermezzo®, and Zolpimist®. The first letter of a brand name should be capitalized, as it is the official name patented by the drug manufacturer. It is important to know or at least be familiar with brand and generic names for the top 200 medications, as they are used frequently in practice.

Medication Classifications

Pharmaceuticals are classified into drug classes based on how they work, or their mechanism of action, and how they affect the body. Often, the suffix of a drug’s generic name indicates its drug class. For example, pharmaceuticals that end with -olol (e.g., metoprolol and propranolol) are blood pressure-lowering agents known as beta-blockers. Sometimes, the prefix of a drug’s generic name will indicate its drug class. For example, pharmaceuticals that begin with cef-/ceph- (e.g., ceftriaxone and cephalexin) belong to the antibiotic class of medications known as cephalosporins.

Therapeutic Equivalence and Duplications

Therapeutic equivalence is designated when two drug products meet strict criteria for interchangeability in accordance with the Food and Drug Administration (FDA) Orange Book. Pharmaceutical equivalents, pharmaceutical alternatives, and therapeutic equivalents all fall under the umbrella of therapeutic equivalence. By law, a generic medication that shows therapeutic equivalence must be substituted for the brand name product when filling a prescription, unless a generic is not yet on the market or the prescriber deems the brand medically necessary.

Therapeutic equivalence should not be misinterpreted as meaning therapeutic duplication. Although they may sound similar, they are distinct concepts. A therapeutic duplication occurs when medications in the same drug class or medications indicated for the same disease state are prescribed together without any clear reason why or if they should be used concurrently by the patient. Typically, medications within the same drug class are not prescribed together, since they work in the same way. For example, lisinopril and captopril are both angiotensin-converting enzyme (ACE) inhibitors, which are used to treat high blood pressure. If a patient were taking both of these medications together, it would be considered a therapeutic duplication.

A therapeutic duplication can also occur by taking medications from different drug classes concurrently, where there is no therapeutic benefit. For example, lisinopril (an ACE Inhibitor) and losartan (an angiotensin II receptor blocker [ARB]) belong to different drug classes but are both indicated to treat high blood pressure. As such, there is no therapeutic benefit for a patient to be on both at the same time. Therefore, they should not be prescribed together. A therapeutic duplication can lead to unwanted adverse effects and unnecessary healthcare costs.

Minimizing Therapeutic Duplications

Therapeutic duplications can be minimized by the entire pharmacy team doing their due diligence. The pharmacist can catch therapeutic duplications during the drug utilization review (DUR). This is when they review the patient’s medication profile when filling each prescription to ensure there are no unwanted interactions or duplications.

Duplications can also be identified during medication therapy management (MTM) programs. With MTM, the pharmacist meets with the patient one on one (either over the phone or in person) to go over all of their prescribed and over-the-counter (OTC) medications and herbal supplements. This allows the patient and pharmacist to discuss any questions or concerns regarding the patient’s medication regimen. The pharmacist reviews the medications with the patient and helps identify barriers to treatment as well as opportunities to optimize their medication management.

The pharmacy technician also plays a role in identifying possible therapeutic duplications by scanning the patient’s medication profile during prescription intake and ensuring the patient’s profile is up to date during each interaction.

Examples of Therapeutic Duplications

Here are some more examples of therapeutic duplications that are not recommended:

• ibuprofen and naproxen—Both of these are nonsteroidal anti-inflammatory drugs (NSAIDs) used to treat mild to moderate pain. Duplication of these drugs can lead to an increased risk of bleeding and kidney problems.

• fluoxetine and duloxetine—This selective serotonin reuptake inhibitor (SSRI) and serotonin–norepinephrine reuptake inhibitor (SNRI) are both used to treat depression, but when taken together can lead to an increased risk of serotonin syndrome.

• warfarin and rivaroxaban—These are both blood thinners that, taken together, will increase the risk of major bleeding and hemorrhage.

• oxycodone and fentanyl—These are potent opioids used to treat pain that can increase the risk of respiratory depression and even death if taken together.

Here are a few examples of medications that may be taken together to treat the same indication but could be considered a duplication in therapy if not identified by the prescriber or patient:

• ibuprofen and acetaminophen—mild pain relievers from different drug classes
• pantoprazole and famotidine—a protein pump inhibitor (PPI) and histamine type-\(2\) receptor (H\(2\)) antagonist used to treat heartburn
• citalopram and trazodone—anti-depressants; however, trazodone is prescribed most often to help treat insomnia

Drug Interactions and Contraindications

Drug interactions occur for many reasons and can range in severity from mild to life-threatening. It is essential to educate patients about the potential for drug interactions and to describe any adverse reactions they may experience.

Drug-Disease

Drugs that are used for one condition or disease may worsen or exacerbate another disease. For example, using ibuprofen for pain in a patient with heart failure is a potential drug-disease interaction, as ibuprofen can cause fluid retention and worsen heart failure. If a patient with heart failure tolerates ibuprofen well, then the interaction is not clinically significant; however, if the patient’s heart failure worsens after starting ibuprofen, then a new approach to managing pain should be considered.

Drug-Drug

Interactions between two (or more) prescription drugs are common, can occur for a variety of reasons, and should be evaluated by the pharmacist prior to drug dispensing. Taking multiple medications, being prescribed drugs by multiple healthcare professionals, and using multiple pharmacies can increase a patient’s risk of experiencing a drug-drug interaction. For instance, omeprazole, a medication used to treat heartburn, interacts with the metabolism of clopidogrel, an antiplatelet medication. This combination should be avoided, and an alternative therapy to treat heartburn should be considered. Drug-drug interactions can also occur between prescription and OTC medications.

Drug-Dietary Supplement

It is essential when speaking with patients to inquire about all the medications they take, including vitamins and supplements. For instance, St. John’s wort has a high potential for interactions with prescription drugs. For example, it has been associated with an increased risk of bleeding with the blood-thinning prescription drug warfarin and enhanced effect of prescription drugs used for depression and anxiety. Similarly, vitamin E at high doses has been associated with an increased risk of bleeding; combining vitamin E with warfarin further increases this risk.

Drug-Laboratory

Laboratory test results are rarely affected by medications; however, because test results may be falsely positive or negative, it is important to be aware of the potential for this interaction to occur. For example, finasteride is a prescription drug used to shrink an enlarged prostate. It may reduce a man’s prostate-specific antigen (PSA), a protein that laboratory tests use to screen for prostate cancer. If laboratory results are interpreted without knowledge of the patient taking finasteride (and therefore having a falsely low PSA), it could interfere with the timely diagnosis of prostate cancer. Similarly, biotin is a vitamin that promotes hair, skin, and nail health. However, taking this medication can cause false readings in many laboratory tests, including thyroid-stimulating hormone (TSH) testing.

Drug-Nutrient

Nutrients include vitamin supplements and nutrients from food. Calcium is an essential nutrient that can be ingested in the form of food (milk), dietary supplements (calcium supplement), or an OTC drug (antacid). In any form, taking calcium at the same time as a fluoroquinolone antibiotic (e.g., ciprofloxacin [Cipro®]) has the potential to decrease absorption of the antibiotic in the body, thereby reducing the ability of the antibiotic to fight infection.

Medication Specifications and Calculations

It is important for pharmacy technicians to be familiar with common dosages, dosage forms, strengths, and units. This will make it easier to identify the correct drug, communicate with other healthcare professionals, and even detect potential fake prescriptions. Questions on the PTCB exam about this topic may include calculations.

Strength and Dose

Drug strength is the amount of active drug in any given dosage form. The drug’s strength will be noted immediately after a drug name and is commonly expressed in terms of milligrams (\(\pmb{\text{mg}}\)) or micrograms (\(\pmb{\text{mcg}}\)) for oral tablets or capsules, milligrams per milliliter (\(\pmb{\text{mg/mL}}\)) for liquid preparations, and grams (\(\pmb{\text{g}}\)) for topical creams, gels, and ointments. Drugs may also be available in more than one strength. For example, tablets of the blood-thinning drug warfarin are available as \(1 \text{ mg}\), \(2 \text{ mg}\), \(2.5 \text{ mg}\), \(3 \text{ mg}\), \(4 \text{ mg}\), \(5 \text{ mg}\), \(6 \text{ mg}\), \(7.5 \text{ mg}\), and \(10 \text{ mg}\).

It is important to understand common dosing units and how to convert from one to another. For example, a prescriber might write “levothyroxine \(0.025 \text{ mg}\),” which is equal to \(25 \text{ mcg}\), as it may be listed on the manufacturer’s bottle.

Dosage Forms

The dosage form is another term for a drug’s physical form. Drugs come in various shapes (e.g., tablets, capsules, solutions, creams, and patches) and sizes (e.g., \(25 \text{ mcg}\), \(500 \text{ mg}\), and \(1 \text{ g)}\). One important dosage form to counsel on is a suspension, as it needs to be shaken in order to evenly disperse the suspended particles and deliver a uniform dose to the patient. Some topical medications, like betamethasone, come in several forms, such as an ointment, cream, and emollient.

Administration Routes

Common administration routes include inhalation, oral, nasal, rectal, vaginal, topical, and transdermal. It is of the utmost importance to accurately identify the intended way for a drug to be given. If a patient takes a capsule by mouth instead of inserting it into the rectum, as is directed, drug absorption, safety, and/or efficacy may be compromised. If there is any question about the route of administration, call the prescriber for clarification.

Special Administration and Handling Instructions

Some medications require special storage, administration, and handling. It is important that the patient be made aware of these instructions. Some suppositories, like promethazine (Phenergan®), must be stored in the refrigerator prior to use and should be handled with gloves, as it has the potential to melt at room temperature or even from the body heat from your hands. Also, suppositories come packaged in a foil or hard plastic wrap and must be handled carefully prior to insertion into the rectum. Patients should be instructed on the proper unwrapping and administration techniques.

Duration of Drug Therapy

The diagnosis and other patient-specific factors determine the duration of drug therapy. Chronic conditions, like depression or diabetes, may require ongoing medication treatment. More acute problems, such as pain or an infection, may only require treatment for a few days or weeks. If patients take medication for less or more time than intended, it could lead to problems down the road, such as uncontrolled diabetes or antibiotic resistance. The prescriber sets the duration of drug therapy for each prescription based on the underlying condition and will determine if following up is necessary for chronic conditions.

Calculations Involved

There are many calculations that are involved on the job as a pharmacy technician. These can range from basic arithmetic to using complex formulas. It is essential to recall some clinical pearls that will make calculations a bit less daunting.

Here are some essential conversions to remember:

\(1 \text{ mL} = 20 \text{ gtt (drops)}\) \(1 \text{ tsp} = 5 \text{ mL}\)
\(1 \text{ tbsp} = 15 \text{ mL}\)
\(1 \text{ kg} = 2.2 \text{ lb}\)
\(1 \text{ in} = 2.54 \text{ cm}\)
\(1 \text{ oz} = ~30 \text{ mL}\)
\(1 \text{ pt} = 473 \text{ mL}\)

It is also essential that you know metric system conversions (e.g., \(1 \text{ L} = 1\text{,}000 \text{ mL}, 1 \text{ mg} = 1\text{,}000 \text{ mcg}\)).

These bits of information will help you calculate strength, dosages, and duration of therapy (days supply) with ease.

Let’s try a couple of real-world example problems.

A patient is prescribed the following:

• Drug: morphine sulfate \(100 \text{ mg}/5 \text{ mL}\)
• Directions: \(5 \text{ mg}\) by mouth every \(2 \text{ hr}\) as needed
• Dispensed quantity: \(30 \text{ mL}\)

What is the day supply?

Solution

This will require some simple math. First:

\[100 \text{ mg}/5 \text{ mL} = 20 \text{ mg/mL}\] \[5 \text{ mg} = 0.25 \text{ mL}\]

The drug is taken every \(2\) hours, so to get how much is taken per day, we multiply:

\[0.25 \text{ mL} \times 12 = 3 \text{ mL}\]

The day supply is how long the drug will last, so now we divide the dispensed quantity, \(30 \text{ mL}\), by the daily amount, \(3 \text{ mL}\):

\[30 \div 3 = 10\]

This means that \(30 \text{ mL}\) will last the patient a minimum of \(10\) days.

A patient is prescribed enoxaparin (\(100 \text{ mg/mL}\)) \(1 \text{ mg/kg}\) subcutaneously every \(12\) hours for \(7\) days. The patient weighs \(154 \text{ lb}\). What is the dosing of enoxaparin?

Solution

The first step is converting the pounds to kilograms:

\[154 \text{ lb} \div 2.2 = 70 \text{ kg}\]

Now, we are told there is \(1 \text{ mg}\) per \(\text{ kg}\), so that means:

\[1 \text{ mg} \times 70 \text{ kg} = 70 \text{ mg}\]

As such, the patient is to take \(70 \text{ mg}\) every \(12\) hours for \(7\) days.