Medications Study Guide for the PTCB Exam

Other Common and Severe Effects of Medication

Adverse (unfavorable) drug side effects are common and can range from mild to severe reactions. Patient counseling should include education about potential side effects to watch for and instructions on what to do in case they occur. Although all side effects are considered unintended, most are deemed negative, but some might be regarded as positive, depending on the patient, like weight loss or hair growth.

Side Effects

Side effects for a given drug can often be predicted based on how a drug works. However, since side effects are not part of the intended therapeutic effect(s) of a drug, they are considered unintended. Common side effects include headaches, stomach upset, or dizziness. Some side effects go away over time, while others are expected to continue for as long as a drug is being used. Likewise, some side effects may occur immediately after administration, while others may develop after a few months or not at all. Even with the same drug, side effects may differ by dose, dosage form, and route of administration.

Adverse Effects

Adverse effects are considered more severe than side effects and typically warrant discontinuation of therapy or possibly emergency medical attention based on severity.

Adverse events are those that negatively impact a person’s well-being or their ability to manage their disease. For instance, muscle pain and cramping are common side effects of statin medications used to treat high cholesterol. However, severe unexplained muscle pain accompanied by dark (tea-colored) urine is an adverse effect of statin medications, indicating extensive muscle breakdown (scientifically known as rhabdomyolysis). This would warrant complete discontinuation of the specific statin drug and a consultation with the physician to seek alternative therapy.

Allergies

While a drug’s most common side effects can often be predicted, allergies are much less predictable because the body’s immune response differs significantly from person to person. Allergic reactions account for just 10% of all drug side effects; however, allergic reactions can be life-threatening. Anaphylaxis is the most serious allergic reaction and can result in hives, swelling of the face or throat, wheezing, and even death. Antibiotics are the most common cause of anaphylactic reactions.

It is important to note that some patients are allergic to inactive (non-drug) ingredients, such as gluten or certain dyes. Drug compounding allows for medications to be made to suit specific patient needs such as these. When asking a patient about allergies, it is important to also write down the reaction type. Anaphylaxis to a medication is considered a true allergy, while upset stomach is not.

Indications of Medications

The indication of legend is the reason a prescription, OTC drug, or dietary supplement has been prescribed or recommended, in keeping with the drug’s FDA approval (or legend). The dosage and duration of therapy for a drug may differ by indication. For example, the starting dose of sertraline (Zoloft®) for post-traumatic stress disorder is 25 mg once daily, but for major depressive disorder, it is 50 mg once daily. Finally, if a drug is prescribed for a reason other than its indicated legend, then that drug is being used “off-label”.

To put it simply, a primary indication is the FDA-approved use of the medication. An off-label use is not an FDA-approved indication for the medication; however, it may be prescribed as such by a practitioner based on clinical evidence and newer clinical findings.

Common Medication Indications

A pharmacy technician must be familiar with common medication names, their drug class, and indication(s) to help ensure proper medication dispensing and identify a possible medication error before it happens.

Here is a list of common medications with their indication of legend:

Medication Name	Drug Class	Indication
acetaminophen	pain reliever (COX-2 inhibitor)	mild to moderate pain, fever
oxycodone	pain reliever (opioid)	moderate to severe pain
penicillin	antibiotic	bacterial Infection
lisinopril	anti-hypertensive (ACE inhibitor)	high blood pressure
omeprazole	PPI	GERD; heartburn
levothyroxine	thyroid hormone	hypothyroidism
atorvastatin	lipid-lowering agent (HMG-CoA reductase inhibitor)	high cholesterol
albuterol	inhaled bronchodilator (beta-2 agonist)	asthma, COPD
diphenhydramine	antihistamine (H1 antagonist)	allergic reactions, allergies
metformin	antidiabetic (biguanide)	type 2 diabetes mellitus

Drug Stability

Pharmaceutical stability is essential to maintain the integrity and safe use of the medication product. Regardless of whether it is a bottle of insulin or an antibiotic suspension, all medication products must be handled and stored correctly to maintain the integrity of the drug. Medications can become spoiled, resulting in a loss of drug stability. When this happens, the drugs should not be used, as the potency and integrity will have been compromised.

Oral Suspensions

Oral suspensions are medications that are supplied in a manufacturer’s bottle as a powder. These products can be stored at room temperature until the expiration date on the container is met. However, the powder must be mixed with the indicated amount of water before dispensing to form a suspension. Once mixed with water, the oral suspension must be given a beyond-use date (BUD) based on the manufacturer’s stability testing data. For example, amoxicillin oral suspension must be discarded 14 days after reconstitution, with recommended storage in the refrigerator.

Suppose you have reconstituted amoxicillin 250 mg/5 mL on July 17 and stored it in the refrigerator. The label states: “Stable for 14 days refrigerated.” The BUD would be July 17 plus 14 days, meaning July 31.

Insulin

All insulins must be stored in the refrigerator before use, ensuring stability until the expiration date indicated on the package label. Once in use, it is only suitable for a limited period, depending on the type of insulin. Once in use, insulin aspart (NovoLog®) is stable for up to 28 days at room temperature, while insulin detemir (Levemir®) is stable for up to 42 days at room temperature.

Suppose you have a vial of insulin aspart that was opened on July 1st. The package insert states that it’s stable for 28 days at room temperature. What is the discard date? You add 28 days to July 1 and get July 29.

Reconstitutables

Medications that are supplied as a dry powder require reconstitution with a diluent (e.g., sterile water or 0.9% NaCl) before use. Many medications are manufactured in dry powder form to allow an extended shelf life. For example, vancomycin is an antibiotic that comes in dry powder form in a vial. This medication must be reconstituted with the correct amount of water prior to adding to an IV bag. There is also clindamycin/benzoyl peroxide (BenzaClin®), which is a topical medication used to treat acne. Prior to dispensing to the patient, it must be mixed with the correct amount of sterile water and given an expiration date of three months.

You could be in a situation where you have a ceftriaxone 2 g vial that has been reconstituted with sterile water for injection. The vial is stored at room temperature and is stable for 24 hours. If the product was reconstituted at 1 p.m. on Tuesday, what date and time should it not be used beyond? Add 24 hours to the time and you arrive at a BUD of Wednesday at 1 p.m.

Injectables

Some injectables are commercially available and can be dispensed to patients with a valid prescription, while others must be prepared and administered in a hospital or doctor’s office. Each has a different level of stability and expiration date based on the manufacturer’s testing data. Ceftriaxone (Rocephin®) is an antibiotic used to treat a variety of infections. Once reconstituted, it is stable for 24 hours at room temperature and can be administered intramuscularly. Dulaglutide (Trulicity®) is a subcutaneous injectable used to manage type 2 diabetes. It can be stored in the refrigerator until the package expiration date, but is only stable for up to 14 days unrefrigerated.

Now, suppose you have a multi-dose vial (MDV) of methylprednisolone that was opened on May 10. According to USP <797>, MDVs are good for 28 days once opened unless the manufacturer specifies otherwise. So, what is the discard date? Simply add 28 days to May 10, which is 21 days of May and seven days of June. So, June 7 is the discard date.

Vaccines

Vaccines are fragile and must be stored properly to maintain integrity and minimize deterioration. Inadequate storage and handling can lead to vaccine ineffectiveness in addition to loss of inventory and money due to spoiled product. All live and attenuated vaccines must be stored in the refrigerator between 35 to 46 degrees Fahrenheit, except for Zostavax®. Zostavax is a live vaccine that must be stored in the freezer prior to administration. Once a vaccine is removed from the refrigerator or freezer, it should be administered to the patient without delay to decrease the risk of degradation.

Suppose a pharmacist reconstitutes the MMR vaccine, which must be used within eight hours of reconstitution and kept in the refrigerator. If the vaccine was reconstituted at 10 a.m., when should it be used by? Again, this is simple addition: Add 8 to 10 to arrive at 6:00 p.m.

Incompatibilities

Incompatibility occurs when two medications are mixed and result in an unsuitable product, either by physical or chemical means. Physical incompatibilities can typically be seen, while chemical incompatibilities may or may not be visible.

Physical

Physical incompatibilities typically result in a change that can be seen by the naked eye. You should always check the physical product after making the compound to make sure it is stable and compatible. Signs of incompatibility include:

formation of a precipitate
a color change from the original product
separation of the ingredients
unexpected cloudiness

Note: Not all physical incompatibilities are visible.

Physical incompatibilities can often be corrected by adjusting the solvents, ingredient forms, suspending agents, or the order of mixing, among other factors. However, some medications are just incompatible altogether and should never be combined. An example of a physical incompatibility occurs with the addition of calcium to ceftriaxone. This combination results in a precipitate that is lethal if administered.

Chemical

Chemical incompatibilities typically result in a change in the chemical makeup of the compounds that the naked eye cannot see. Still, the end product is either toxic, inactive, or unstable. These are some chemical reaction types that may occur between products:

change in pH
decomposition/degradation
hydrolysis
oxidation-reduction reactions

Medication Storage

All drugs used in the pharmacy have storage requirements. Drugs can be kept at room temperature, under refrigeration, or in the freezer, depending on drug storage requirements. Some medications may also have specific storage requirements, including light levels or moisture restrictions.

Temperature Ranges

Room temperature is defined as between 68 and 77 degrees Fahrenheit (°F). Refrigerated drugs need to be kept at 36 to 46°F. Drugs stored in the freezer are kept between -13 and 14°F. If a drug has no specific storage requirements, it should be kept at room temperature.

Light Sensitivity

Some medications are photosensitive, or sensitive to light, and have the potential to degrade if not stored properly. When dispensing a prescription, pills are usually counted out from the original manufacturer’s container and dispensed in a patient-specific, labeled amber bottle. Amber bottles are used for dispensing as the color helps deflect rays of light. Some medications, like nitroglycerin, have special storage requirements and must be dispensed in the original manufacturer’s container.

Restricted Access

Medications that have a risk of being misused and abused for their therapeutic properties are categorized as controlled substances by the Drug Enforcement Administration (DEA). Controlled substances are classified based on their risk potential and are scheduled from I-V. These can also be referred to as “CI” through “CV.”

Controlled substances that are available on the US market with a therapeutic benefit range from II-V. The lower the schedule, the higher the risk of potential misuse and abuse of the medication. Schedule I controlled substances have no current acceptable medical use and are not prescribed or available on the US market (e.g., marijuana, heroin). Oxycodone is a schedule II controlled substance, while lorazepam is a schedule IV. So, oxycodone has a higher risk of misuse/abuse/dependence than lorazepam.

Medications considered controlled substances are stored in a restricted access area of the pharmacy. With that being said, the patient who is prescribed these medications should also ensure they are stored in a safe place away from children, adolescents, and even the general public. Controlled substances in the categories from CIII to CV, like lorazepam, zolpidem, and buprenorphine, can be kept with the regular medication inventory of a pharmacy; however, some pharmacies still opt to keep them in a more restricted access area.

Schedule II medications have the highest abuse potential on the market and must be kept locked away, typically in a vault or cage. Examples of medications classified as CII include opioids, including oxycodone and fentanyl, and ADHD medications, such as Vyvanse® and Adderall®.