The Medicine Aisle, Decoded:

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Article posted by Daniel Biondi, DO, MBA

What Patients Should Know Before Buying Over-the-Counter Medications

Walk into any pharmacy, grocery store, or gas station, and you'll find rows of brightly colored boxes promising relief from headaches, back pain, colds, heartburn, and more. Over-the-counter (OTC) medications are convenient, and when used correctly, they're helpful. But "available without a prescription" doesn't mean "safe for everyone, in any amount, for any length of time."

Here's what we want every patient to know before they reach for that next box.

Many "different" pain relievers are the same medicine

Most OTC pain relievers contain one or more of just a handful of active ingredients:

  • Acetaminophen (Tylenol and store brands)
  • Ibuprofen (Advil, Motrin IB and store brands)
  • Naproxen (Aleve and store brands)
  • Aspirin (Bayer, Bufferin, Ecotrin and store brands)
  • Sometimes combined with caffeine, which can boost pain relief

Manufacturers often package these same ingredients for different uses: "Back Pain," "Migraine," "Menstrual Relief," "Arthritis," "Headache," "Body Pain." The box design and price may change, but the medicine inside often doesn't. Some products sold as "migraine" and "extra strength headache" versions contain identical ingredients in identical amounts.

What this means for you:

  • Read the "Drug Facts" label, not the front of the box. The active ingredients and their amounts are listed at the top.
  • Store brands work the same. A store-brand ibuprofen 200 mg contains the same active ingredient as the name brand, usually for less money.
  • Don't double up by accident. Taking a "back pain" product and a "headache" product together could mean taking twice the dose of the same medicine.

Why doubling up matters

  • Acetaminophen is safe at recommended doses, but too much can cause serious liver damage. It is hidden in many products, including nighttime pain relievers, multi-symptom cold and flu medicines, and some prescription pain medications (for example, those labeled "APAP" or containing hydrocodone or oxycodone with acetaminophen). Drinking alcohol regularly raises the risk.
  • Ibuprofen, naproxen, and aspirin belong to a group called NSAIDs. Taking more than one NSAID at a time, or taking them for long periods, increases the risk of stomach ulcers and bleeding, kidney problems, and raised blood pressure. NSAIDs can also affect people with heart disease.

Cold and allergy medicines: the combination problem

Multi-symptom cold, flu, sinus, and allergy products often combine several drugs in one dose. For example:

  • A pain reliever/fever reducer (often acetaminophen)
  • A decongestant (pseudoephedrine or phenylephrine)
  • An antihistamine (diphenhydramine, doxylamine, chlorpheniramine, or others)
  • A cough suppressant (dextromethorphan)
  • An expectorant to loosen mucus (guaifenesin)

That can be convenient, but it creates real risks:

  • Duplication. Taking a daytime cold medicine plus a separate pain reliever may double your acetaminophen. Taking a nighttime cold medicine plus an OTC sleep aid may double your antihistamine.
  • Treating symptoms you don't have. If you only have a stuffy nose, a single-ingredient product may be the better choice.
  • Interactions with prescriptions. For example:
    • Decongestants can raise blood pressure and heart rate. They may not be appropriate if you have high blood pressure, heart disease, glaucoma, thyroid disease, or an enlarged prostate.
    • Dextromethorphan can interact with certain antidepressants and other medications that affect serotonin.
    • Sedating antihistamines (like diphenhydramine) add to the drowsiness from alcohol, sleep aids, anxiety medications, opioids, and muscle relaxants. They can cause confusion, falls, constipation, and trouble urinating, especially in older adults.

Tip: Choose products that treat only the symptoms you have, and check every label for repeat ingredients.

Stomach and urinary products: surprises and cautions

Some OTC products cause harmless but alarming side effects. Others can hide a more serious problem or interfere with other medications.

Pepto-Bismol and similar products (bismuth subsalicylate)

  • Black stool or a black tongue is common and harmless. It goes away after you stop the medicine.
  • But black, tarry stool can also signal bleeding in the stomach or intestines. If you have black stool along with dizziness, weakness, stomach pain, or vomiting blood or "coffee grounds," seek care right away. Don't assume it's the medicine.
  • It contains a salicylate, which is related to aspirin. Avoid it if you're allergic to aspirin, take a blood thinner, or already take aspirin. Don't give it to children or teenagers recovering from flu-like illness or chickenpox because of the risk of Reye's syndrome.

AZO and other urinary pain relievers (phenazopyridine)

  • It turns urine bright orange or red. This is expected. It can also stain clothing and contact lenses.
  • It relieves burning but does not treat a urinary tract infection. An untreated UTI can spread to the kidneys. The label limits use to 2 days. If symptoms last longer, or you have fever, back pain, or blood in your urine, see a provider.
  • It can affect urine test results. Tell your clinic if you've taken it before a urine test.
  • The brand sells several different products. AZO also sells cranberry supplements and UTI test strips. Make sure you know which one you're buying.

Antacids, acid reducers, and other GI medicines

  • Antacids (calcium carbonate, magnesium, aluminum) can block the absorption of certain antibiotics, thyroid medication, and iron. You may need to space doses a few hours apart. Ask your pharmacist.
  • Acid reducers such as omeprazole are labeled for a 14-day course, no more than a few times per year, without a doctor's guidance. Frequent heartburn deserves a medical evaluation.
  • Anti-diarrheals such as loperamide should not be taken above the labeled dose. Avoid them if you have fever or bloody diarrhea unless a provider directs you to use them.

Vaginal yeast infection treatments

  • Miconazole products can raise the effect of the blood thinner warfarin and increase bleeding risk.
  • If it's your first yeast infection, you're pregnant, or symptoms keep coming back, see a provider first.

Your pharmacist: an expert you can talk to for free

Pharmacists are medication experts, and you don't need an appointment to ask a question. When you buy OTC medicine at a pharmacy, you can:

  • Ask whether a product is safe with your prescriptions, health conditions, and allergies.
  • Get help choosing the simplest, most appropriate product for your symptoms.
  • Have your purchase checked against your medication list if you fill prescriptions there.
  • Buy some medicines, like pseudoephedrine, that are kept behind the counter.

When you buy at a gas station, convenience store, or dollar store, no one is there to answer questions. Those products may be perfectly fine, but you're making the decision on your own.

Tips:

  • Use one pharmacy for all your prescriptions when possible, so your pharmacist sees the whole picture.
  • Keep an up-to-date list of every prescription, OTC medicine, vitamin, and supplement you take. Bring it to every appointment.
  • Ask: "I take ____. Is this safe with it?"

OTC medications are meant for short-term use

OTC medicines are designed to treat minor, temporary problems. The label tells you how long it's safe to use them on your own. Common limits for adults include:

  • Pain relievers: no more than 10 days for pain or 3 days for fever without talking to a provider.
  • Urinary pain relievers (phenazopyridine): no more than 2 days.
  • Acid reducers (like omeprazole): a 14-day course.
  • Nasal decongestant sprays: usually no more than 3 days, because longer use can cause "rebound" congestion.

If you need a medicine beyond the label's time limit, that's a signal to get evaluated. The medicine may be covering up a condition that needs different treatment.

Get medical care promptly if you have:

  • Chest pain, trouble breathing, or a severe or "worst ever" headache
  • A fever above 103°F, or any fever lasting more than 3 days
  • Blood in your stool, urine, or vomit, or black, tarry stools
  • Symptoms that get worse or keep coming back
  • New symptoms after starting a medication

Who should check before taking any OTC medicine?

Talk with a pharmacist or provider first if you:

  • Are pregnant or breastfeeding
  • Are buying for a child (dosing is based on age and weight, and some products aren't safe for children)
  • Are 65 or older
  • Have kidney disease, liver disease, heart disease, high blood pressure, diabetes, stomach ulcers, or a bleeding disorder
  • Take a blood thinner, antidepressant, blood pressure medicine, diabetes medicine, or any daily prescription
  • Drink alcohol regularly

The bottom line

OTC medications offer convenience, not a guarantee of safety. Before you buy:

  1. Read the Drug Facts label, not just the front of the box.
  2. Know your active ingredients and avoid taking the same one twice.
  3. Choose products that treat only the symptoms you have.
  4. Ask your pharmacist, especially if you take other medications or have health conditions.
  5. Respect the time limits, and see a provider if symptoms don't improve.