Questions concerning pharmacology will occupy nearly 14% of the Pharmacy Technician Certification Board (PTCB) exam. You’ll need to know all about drugs, their interactions and side-effects, as well as common dosages. Follow the outline below as you study and be sure to seek additional information about concepts that give you trouble.
Like in any other profession, knowing and using the appropriate vocabulary is an important part of the job. Being familiar with common pharmaceutical names and spellings will make it easier to understand patients and communicate with other healthcare professionals. In the realm of pharmacy, it is crucial to be exact with names and spelling, since two medications may have very similar names but be used for vastly different purposes.
Brand names are typically shorter than generic names; therefore, drug manufacturers often use brand names to advertise new drugs. It is important to note that one generic drug may have multiple brand names, depending on drug formulation and manufacturer (e.g., zolpidem is found in Ambien, Edluar, Intermezzo, and Zolpimist). The first letter of a brand name should be capitalized, as it is patented by the drug manufacturer.
Generic drugs are lower-cost versions of brand name drugs. Pharmaceuticals are classified into drug classes based on how they work. Oftentimes, 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.
Over-the-counter (OTC) drugs are simply those that can be bought without a prescription. The U.S. Food and Drug Administration has deemed them safe and effective when patients follow the directions on the label and as directed by a healthcare professional.
Herbal and dietary supplements can often be purchased without a prescription, but they are regulated differently than OTC drugs by the U.S. Food and Drug Administration. Vitamins, minerals, and herbs are all considered “dietary supplements” because they contain “dietary ingredients” meant to add nutritional value to one’s diet. It is important to ask patients specifically if they are taking any dietary supplements, and offering examples of these (echinacea, garlic, ginkgo biloba, ginseng, and St. John’s Wort) can help trigger a patient’s memory.
Therapeutic equivalence is designated when two drug products meet strict criteria 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.
Drug interactions occur for many reasons and can range in severity from mild to life-threatening. It is important to educate patients about the potential for drug interactions to occur and to describe any adverse reactions they may experience.
Obtaining an accurate and complete medical history for a patient is necessary for understanding how best to care for that individual. Having a complete understanding of a patient’s allergies, medical problems, and medication history helps healthcare professionals select the most beneficial pharmaceuticals for a patient while avoiding potential interactions.
Drugs can interact with other drugs, diseases, and even laboratory results. Common interactions will vary depending on practice setting (e.g., community and hospital). It is important to remember that individual responses to interactions will vary.
Drugs that are used for one disease may worsen 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.
Interactions between two (or more) prescription drugs are common, can occur for a variety of reasons, and should be evaluated 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.
OTC drugs can interact with other OTC drugs or prescription drugs; however, patients can purchase OTC drugs without first talking to their physician, pharmacist, or other healthcare professional, so they may not be aware of potential OTC-drug interactions. For example, if a patient is prescribed an acetaminophen-containing drug [e.g., oxycodone/acetaminophen (Percocet)] then also purchases OTC acetaminophen (the active ingredient in Tylenol), there is an increased risk of serious liver damage.
St. John’s Wort has the most 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.
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 (a prescription drug used to shrink an enlarged prostate) may reduce a man’s prostate-specific antigen (PSA), a laboratory test used 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.
Nutrients include vitamin supplements and nutrients from food. Calcium is an essential nutrient that can be ingested in the form of food (milk), dietary supplement (calcium supplement), or 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 decreasing the ability of the antibiotic to fight infection.