A grab bag of risks

Although over-the-counter drugs taken at the recommended doses rarely cause dangerous side effects in healthy people, they can cause a number of unpleasant symptoms. Those include insomnia and irritability from oral decongestants, constipation from aluminum-containing antacids, diarrhea from magnesium-containing antacids, and indigestion from all pain relievers except acetaminophen (Tylenol). One common side effect – drowsiness from antihistamines, which are contained in all allergy drugs and some cold medications – could be more hazardous. In fact, the maximum recommended dose of some antihistamines can slow reaction time more than the amount of alcohol that would make driving illegal in most states.

The risk of side effects from over-the-counter drugs increases sharply when people take more than they should. For example, swallowing just three times more than the maximum recommended dose of phenylpropanolamine – contained in the oral decongestant Propagest, many cold remedies, and all diet pills – can cause severe and even life-threatening rises in blood pressure. Taking a drug continually without consulting a doctor also multiplies the risk of side effects, such as anemia from chronic use of aspirin or potassium depletion and bowel damage from excessive use of the laxative bisacodyl (Carter’s Little Pills, Dulcolax, Fleet Bisacodyl).

Further, overuse of certain nonprescription drugs can lead to an insidious form of dependency. People who keep taking drugs to relieve headaches or nasal congestion will often get “rebound” symptoms – headaches or congestion worse than the original symptoms – as soon as the drug starts wearing off. That may lead to a vicious cycle of increasingly frequent use of the drug and worsening rebound. Similarly, prolonged use of laxatives can weaken the bowel muscles, causing renewed constipation as soon as the drug is discontinued.

The gravest danger from sustained use of over-the-counter medications is that you might be controlling symptoms while allowing an underlying disease to go untreated. For example, people with stomach pain sometimes take over-the-counter antacids or pain relievers for months without seeing a doctor. Those people may have ulcers or inflammation of the stomach, which can cause serious bleeding; or they may even have stomach cancer.