OTC Medicines: Know Your Risks, and Reduce Them

You can buy over-the-counter (OTC) medicines without a prescription from your doctor. OTC medicines can help treat or prevent symptoms from illness or other health problems, such as allergies. However, sometimes OTC medicines can cause unpleasant effects, which are also called adverse effects. These adverse effects include side effects, drug-drug interactions and food-drug interactions. It is best to be aware of the risks so you know how to avoid them.

Certain situations put you at higher risk for adverse effects. Because the possible adverse effects differ from one OTC drug to another, you must carefully read the label of any OTC medicine to know what to expect.

Although OTC medicines have a low risk of adverse effects when used occasionally by adults who are generally healthy, they can pose greater risks for some people, including very young children, the elderly and people taking more than one type of medicine. People who have the following conditions are also at a higher risk:

Even though these conditions put some people at greater risk, it is important to remember that anyone can experience an adverse effect from a medicine.

When you take any type of medicine, it’s important to be aware of changes in your body and how you feel. It may be hard to know whether a certain symptom is caused by your illness or by an adverse effect from your medicine. Tell your family doctor when the symptom started and if it is different from other symptoms you have had.

Side effects are effects that drugs have on your body that don’t help your symptoms. They’re most often unpleasant. A few examples are nausea, feeling dizzy or bleeding in your gastrointestinal (GI) tract. Sometimes, side effects can be useful. For example, certain antihistamines can cause sleepiness. This might be bad for people who take antihistamines during the day to treat allergies. But if you are taking an antihistamine at nighttime, this side effect might help you get the sleep you need.

The body processes (metabolizes) every drug differently. When medicines are used together (whether prescription or OTC) their effect on the body can change, called a drug-drug interaction. This increases the chance that you will have side effects from each drug you are taking. The following are the main interaction types:

Duplication: If you take two medicines that have similar active ingredients, you may get more of an ingredient than you need. An example is when you take OTC ibuprofen along with a prescription anti-inflammatory medicine given to you by your doctor. Too much of either an anti-inflammatory medicine or acetaminophen (one brand name: Tylenol) can hurt your liver. You should be aware of all the active ingredients in the medicines you take. Be sure to check each new medicine to avoid duplication.

Opposition (antagonism): Medicines with active ingredients intended to have opposite effects on your body can interact, which may reduce the effectiveness of one or both medicines. For example, OTC decongestants can cause opposition when taken with certain medicines intended to lower your blood pressure, because decongestants may raise your blood pressure.

Alteration: One medicine may change the way the body absorbs, spreads or metabolizes another medicine. For example, aspirin can change the way certain prescription blood thinning medicines work.

If you see more than one doctor, tell each of them about the medicines you take — even if you take something for just a short time. Include any herbal supplements, vitamins and minerals you take. At least once a year, bring all of your medicines and supplements with you when you see your doctor.

Foods may affect how some OTC or prescription medicines are processed by your body. This is called a drug-food (or drug-nutrient) interaction. Sometimes what you eat and drink can affect the ingredients in a medicine you’re taking and prevent the medicine from working the way it should. For example, medicines taken by mouth (orally) must be absorbed through the lining of the stomach or the small intestine. The nutrients from the food you eat are also absorbed here. So if you take a medicine with food when it’s not recommended, one possible interaction is that your body might not be able to absorb the medicine as it should.

No. But some OTC medicines can be affected by what you eat and when you eat it. This is why some medicines should be taken on an empty stomach (one hour before eating or two hours after eating). On the other hand, it’s easier for your body to process certain medicines when you take them with food.

Read the drug label to see if you should take your medicine with a snack or a meal, or if it should be taken on an empty stomach. If the label doesn’t give specific directions, taking the drug with or without food probably won’t affect the way the drug works. If you have any questions, ask your family doctor or pharmacist.

Often, older adults use many drugs at the same time, including prescription and OTC medicines. Their bodies also process drugs differently than younger adults. This is why older adults need to pay careful attention to drug-drug interactions between OTC and prescription medicines. If you are an older adult, talk with your doctor about all of the drugs, vitamins and herbal supplements you take. Your doctor can tell you whether you are at risk for having an adverse effect from taking an OTC medicine. The following are a few of the problems that older adults may be at an increased risk for:

In general, be careful about mixing alcohol and any OTC or prescription medicine. Check drug labels for warnings about drinking alcohol while taking OTC medicines. Drinking alcohol while taking any of the following medicines is especially risky:

NSAID pain relievers. If you drink more than one alcoholic beverage per week and use NSAIDs you may be at increased risk of gastrointestinal (GI) bleeding. People who consume three or more alcoholic beverages each day should consult their physician before using any pain reliever. Examples of NSAIDS include ibuprofen (two brand names: Motrin, Advil), aspirin, naproxen (one brand name: Aleve) and ketoprofen.

Acetaminophen. This medicine is much less likely than NSAIDs to be associated with gastrointestinal (GI) bleeding. However, be careful when taking acetaminophen (one brand name: Tylenol) if you drink alcohol because both can damage your liver.

Certain OTC antihistamines. Using these medicines while drinking alcohol can increase drowsiness.

Decongestants and cough medicines. Drinking alcohol while taking the cough suppressant dextromethorphan (two brand names: Robitussin, Vicks) can increase drowsiness.

Herbal supplements. Alcohol should not be mixed with valerian root, St. John’s wort or kava kava because it increases the risk of drowsiness.