Although often overlooked, over-the-counter (OTC) medicines are a key component of today’s healthcare system. According to the Consumer Healthcare Products Association (CHPA), nearly 81% of American adults utilize over-the-counter (OTC) medicines as a first response to minor ailments. Similarly, it is also noted in one study that OTC products can save up to $34 billion in annual workplace productivity as a byproduct of making workers improve symptomatically.
Directly correlating with their prevalent usage, there is a high coinciding degree of OTC misuse. Some misuse is intentional, such as abusing certain products to procure illicit substances. However, the majority of OTC misuse is unintentional. This article focuses on the primary ways by which individuals inadvertently misuse OTC products.
The majority of pharmacists’ OTC product interventions relate to dosing advice and product selection. Without these interventions, it is easy to misuse a product by not using it correctly and/or by not selecting the most optimal product in the first place.
The list below dissects important minimum considerations for utilizing OTC medications. These considerations are also common interventions that community pharmacists make for patients on a daily basis.
1. Active Ingredient Duplication – Combination Products and Stand-Alone Products
Many medicines are available as stand-alone products. That is to say, there is only one active ingredient in the medicine. Advil is an example of this – the only active ingredient in Advil is ibuprofen.
There are also combination products available that contain multiple active ingredients in a single pill, liquid, or cream. For example, DayQuil contains acetaminophen (active ingredient in Tylenol), dextromethorphan (active ingredient in Robitussin), and phenylephrine (a nasal decongestant).
Often, individuals take combination products alongside other combination products or stand-alone products. Without paying close attention to ingredients that are contained within each product, it is easy to duplicate active ingredients needlessly
When active ingredients are duplicated, enhanced side effects or toxicities may ensue. A common example of this type of duplication, extending on the DayQuil example, is somebody taking Tylenol for fevers alongside DayQuil for cold symptoms. Both products contain acetaminophen, and taking too much acetaminophen is ill-advised. For this example, this could lead to liver injury if too much acetaminophen is ingested.
Although this is a common trend in cough and cold products, this duplication can occur in nearly all OTC product groupings.
Takeaway: it’s important to be cognizant of which active ingredients are contained in specific products. If the same active ingredient is in multiple products, make sure to check with a pharmacist or physician to ensure that the medicines are safe to take together.
2. Duplication of Therapeutic Categories
Similar to the point above, duplication of therapy is of important concern.
This concern isn’t as much related to dosages. Moreso, this relates to duplicating medicines from the same therapeutic category. This commonly can happen as a result of confusing brand and generic names, not knowing different indications for different medications, or some combination of the two.
For one example, someone may purchase bottles of both Zyrtec and loratadine. Different names and branding are printed on the bottles, so it might be easy to miss that these medicines fall into the same category of non-drowsy antihistamines. By taking both products at the same time, there is no additional benefit.
For another example, someone may purchase both Advil (ibuprofen) and Aleve (naproxen) thinking that they could help reduce pain and inflammation via different mechanisms. However, both of these medications fall into the class of drugs called non-selective non-steroidal anti-inflammatory drugs (NSAIDs). By taking both of these products at the same time, no additional benefit would be gained and adverse events could also occur as a result. For this example, someone ingesting both ibuprofen and naproxen could experience kidney injury.
For a third example, someone experiencing acid reflux may seek to obtain self-treatment to reduce the amount of stomach acid causing esophageal irritation. Multiple OTC product options are available to treat acid reflux, with Tums (calcium carbonate), Pepcid (famotidine), and Prilosec (omeprazole) all being examples of viable treatment options. Although these medicines technically fall into different drug categories, they are utilized for a similar purpose and it is not advisable to duplicate these therapies without the guidance of a prescribing physician.
Takeaway: if you aren’t sure if one medicine is similar in indication/purpose to another medicine, ask your pharmacist.
3. Dosing Inaccuracies
Without education related to dosing insights, it’s easy to be confused over how much drug should be taken or administered.
For liquids, this primarily relates to issues with measuring out medicine. Liquid medication quantities can be given in milliliters (mL), cubic centimeters (CC), teaspoons (tsp), tablespoons (tbsp), etc. It can be easy to mix up converting quantities (mL to tsp, or vice versa, for example). Additionally, not everybody has measuring devices at home that reflect the recommended dosing on a medication container. For example, if a product calls for 5 mL per dose and the only measuring device available is a cooking cup or spoon, it’s hard to know how much would be equivalent to 5 mL.
A best practice is to ask the pharmacy for liquid measuring syringes for proper dose administration – these are typically free of charge and are measured in mL. Milliliter measurements tend to be the most accurate liquid dosing option, especially as measuring doses in spoons can vary based upon the size of the spoon utilized.
Table 1. Common Liquid Dose Conversions
| Measure | Milliliter Equivalent |
| 1 CC | 1 mL |
| 1 tsp | 5 mL |
| 1 tbsp | 15 mL |
| 1 fluid oz | 30 mL |
For tablets and capsules, this relates to not knowing how many pills to take at a time and at a given frequency. Compared to liquids, there is not as much of a concern of converting or measuring out doses. However, common points of confusion relate to how many pills should be taken at a time and at what frequency. If it’s not clearly printed on the product box, make sure to always ask a pharmacist for dosing advice. It is easy to accidentally ingest an overdose of a medication if not taken properly.
For creams and ointments, this relates to how much cream or ointment should be applied at a time and over what surface area on the skin. There’s not a uniform recommendation for how much cream or ointment to apply, so a pharmacist is the best resource to utilize for knowing how much ointment/cream to apply at a given time for a specific circumstance.
Unless instructed otherwise, it’s important only apply one cream/ointment at a time. Mixing multiple creams/ointments on the same surface of skin can render them ineffective or predispose the applicator to an overdose depending on the combination. For example, if someone applies Eucerin cream to their foot and then applies hydrocortisone right afterwards, the hydrocortisone may not be as effective as it would otherwise. Mixing topical medications like this is a common mishap.
Takeaway: always respect the recommended dosing information provided for a specific OTC product. If the information isn’t clear, ask a pharmacist.
4. Improper Indications
This mistake is more simple in nature, but it is still highly prevalent. It’s important to only use products for their indicated purpose. A medication’s intended purpose is typically printed on both the front branding of the package and on the “Drug Facts” label on the back of the package.
Some examples of individuals misusing medications based on indication: using Tylenol (acetaminophen) for cough, Mucinex (guaifenesin) for allergies, Claritin (loratadine) for muscle pain, etc.
Takeaway: if you aren’t sure what a medication is used for, ask your pharmacist.
5. Age Conflicts
Not many medications have maximum age limits, but a comprehensive list exists for maximum age recommendations from the American Geriatrics Society for varying medications. A lot of medications on this embedded list from the American Geriatrics Society relate to prescription-only medicines, but there are numerous medicines that are OTC as well.
For example, chronic Benadryl (diphenhydramine) usage isn’t recommended in older adults as it can exacerbate confusion, cause constipation, and lead to dry mouth. For another example, Pepcid (famotidine) can worsen delirium in older adults that have issues with delirium. As a third example, usage of aspirin without the guidance of a physician in individuals older than 70 years can significantly worsen bleeding risk.
On the other spectrum, nearly all products have minimum age requirements. These minimum age requirements are typically printed on package containers for OTC products. It is important to respect these recommendations. As individuals age, organ function changes, water volume throughout the body changes, and the overall body composition develops. Related to this, the mechanism by which a medication distributes throughout the body, in addition to the way it metabolizes, changes with age. Because of this, some medications are more appropriate than others for young children.
This list from Pharmacist Consult breaks down minimum age requirements for common cough and cold products.
Takeaway: read the back of the product container to understand the product’s minimum age requirements. This is important for safety reasons. If it is not clear, double check with your local pharmacist.
6. Drug Interactions with Prescription Medicines
Drug interactions are a common concern for pharmacists, and pharmacists continuously evaluate ways to mitigate issues related to them. Typically, patients are also aware that drug interactions are possible for prescription medicines.
However, individuals often forget that OTC medications may be just as likely to complicate drug interactions as prescription medicines. To make matters worse, pharmacists do not know which OTC medicines a person takes unless it is directly told to them. Because of this, some drug interactions may fly under the radar.
There are countless examples of drug interactions between OTC products and prescription medicines. For one, concurrently taking warfarin (a blood thinner) and a NSAID (such as Advil) may increase someone’s INR, causing the blood to be too thin. Another example is using St. John’s Wort (a supplement) alongside a medicine such as Lexapro (escitalopram), which could predispose someone to serotonin syndrome.
Takeaway: tell your pharmacist about all OTC medicines that you use so they can help maintain your safety and well-being. This includes vitamins and supplements.
Resources:
- White Paper: Value of OTC Medicines to the U.S. Healthcare System. Consumer Healthcare Products Association (CHPA). Accessed 11 April 2020. http://overthecountervalue.org/white-paper/
- Drug Interactions: What You Should Know. Food and Drug Administration (FDA). Accessed 11 April 2020. https://www.fda.gov/drugs/resources-you-drugs/drug-interactions-what-you-should-know
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