Painkillers, heartburn drugs and laxatives are among the worst offenders.

We hear a lot about overuse of prescription drugs. That’s because every year, more than 20,000 Americans die from a prescription drug overdose. About 75% of those fatalities are from painkillers such as oxycodone (OxyContin) and hydrocodone (Vicodin). But there’s another unexpected threat—and that’s overdosing on over-the-counter (OTC) painkillers.

Believe it or not, the main culprit is acetaminophen—the common pain reliever in Tylenol and other brands. It hospitalizes 30,000 people annually, many of whom develop acute liver failure.

Studies show that one-half to two-thirds of acetaminophen overdoses are the result of victims’ poor understanding of the product’s dosing instructions. One 2012 study published in the Journal of General Internal Medicine tested 500 people to determine their knowledge about and use of acetaminophen.

By their answers, many of the study participants showed that they would overdose—24% by using one product and unknowingly taking more than the safe limit of 4,000 mg (4 g) every 24 hours…and about 46% by using two acetaminophen-containing products at the same time without realizing the combined dosage would be an overdose.

The same misuse of medications and misunderstanding of labels occurs with other types of OTC medications described throughout this article—with potentially disastrous long-term consequences for health. Here’s how to make sure that you don’t overdose on or overuse OTC drugs…

ACETAMINOPHEN

Acetaminophen is the most commonly used OTC drug in the US—every week, one out of every five adults takes it. And for good reason—the drug works fast to reduce pain and fever. In fact, acetaminophen works so well, it’s the main pain-relieving, fever-lowering ingredient in many OTC products for headache, arthritis, back pain, colds, coughs, sinus problems and more. But the effectiveness and availability of the ingredient is a setup for overdosing.

Fortunately, a few simple precautions can help prevent an acetaminophen overdose…

Read the labels and do the math. Read the ingredient list on every OTC drug you take and know which contain acetaminophen and how much. Keep careful track of your daily intake—and don’t ever take more than 1,000 mg at any one time or exceed 4,000 mg in a day. The more acetaminophen-containing products you take, the more likely it is you’ll overdose.

Example: In the Journal of General Internal Medicine overdose study, three drug combinations were most likely to cause an overdose—a pain reliever and a PM pain reliever…a pain reliever and a cough and cold medicine…a sinus medication and a PM pain reliever.

Know if you are at high risk—and be extra-cautious if you are. In the overdose study, people who were “heavy users” of acetaminophen (taking it a couple of days a week or more) were more likely to underestimate their intake—and to overdose.

Important: If you suffer from chronic pain, see your primary care physician or a pain specialist, and ask for a stronger medication that is taken once or twice a day. That way, you won’t have to take as many OTC painkillers.

Know the signs of an overdose. An overdose of acetaminophen typically causes nausea and vomiting, sweating, yellowing of the skin and eyes and a general feeling of flulike illness. Within one to three days, it causes pain in the upper right quadrant of the abdomen (the location of the liver). If you develop those symptoms after regular use of acetaminophen (or after a single dose that is excessive)—seek immediate medical care.

Self-defense: Call 911 or go to a hospital emergency department if you have severe symptoms, such as gasping for air. The standard treatment for acetaminophen overdose is n-acetyl-cysteine (NAC), an antioxidant that reverses liver toxicity, often given intravenously. Although NAC capsules are available at health-food stores, it’s best to be treated by medical personnel since an overdose is a serious medical condition. If you suspect that you may be experiencing symptoms of an overdose, you can call a 24-hour poison control center such as the National Capital Poison Center at 800-222-1222.

PROTON PUMP INHIBITORS (PPIs)

These popular drugs work by slowing down your body’s production of stomach acid, preventing and relieving the symptoms of heartburn. They also are used to treat indigestion (dyspepsia), ulcers and other upper gastrointestinal (GI) problems. Two kinds are available OTC—lansoprazole (Prevacid 24HR) and omeprazole (Prilosec OTC, Zegerid OTC).

The danger: These drugs, if taken daily, should not be used for more than two weeks without a doctor’s approval, according to label instructions. Studies show that overuse can increase risk for hip, wrist or spine fractures in adults over age 50…and cardiac arrhythmias, intense diarrhea, colds, flu and pneumonia, and vitamin and mineral deficiencies in users of all ages. In addition, when you stop taking one of these drugs abruptly, it can trigger rebound acid hypersecretion—a surge of stomach acid that worsens symptoms, forcing you back on the drug for relief.

Self-defense: Slowly wean yourself off long-term use of a PPI. Speak to your doctor about the best way to do this. Afterward, treat heartburn with OTC antacids, a much safer choice (follow label instructions).

NASAL DECONGESTANTS

Many people suffer from rhinitis medicamentosa (RM)—a chronically stuffy nose caused by overuse of nasal decongestant spray. For example, you might use a spray, such as Afrin or Neo-Synephrine containing the ingredient oxymetazoline or phenylephrine, during a cold or allergy season. It provides relief, but there is “rebound congestion” when the spray wears off. You use it again…there is rebound congestion…and you use it again. Soon, you have RM—and are addicted to the nasal spray for “relief.”

Self-defense: If you are addicted to a nasal spray, wean yourself off slowly. (Examples: Alternate nostrils with each use, rather than spraying both nostrils. Or use the spray only at bedtime to get you through the night.) As you decrease use, try a nonmedicated saline spray or a menthol nasal spray and a humidifier or steam vaporizer. You might also ask your doctor for a short-term prescription for nasal corticosteroids, which will relieve congestion while you withdraw from the spray. Plus, address underlying health problems that may cause nasal congestion, such as food allergies or structural problems in the sinuses.

LAXATIVES

Constipation is a common problem, and daily use of OTC laxatives, such as Miralax and Milk of Magnesia, is frequently the “solution.”

The danger: Laxative overuse can lead to abdominal cramping, nausea and vomiting, blood in the stool, mineral deficiencies, electrolyte imbalances that cause heart and kidney damage—and, in rare cases, death.

Self-defense: Wean yourself slowly off laxatives. For example, start by switching from daily use to every-other-day use.

As you’re reducing use, add more fiber to your diet, with fruits, vegetables, whole grains and beans—and, if necessary, take a daily fiber supplement—to help ensure regular bowel movements. Take a probiotic, a supplement of “friendly” bacteria that aids digestive health. Other digestive aids that can help cure constipation include aloe vera, essential fatty acids and digestive enzymes. Talk to your doctor about which of these digestive aids might work best for you. Drink water throughout the day and exercise regularly, which stimulates bowels.

STAY SAFE

Keep all your prescriptions at the same pharmacy. That way, your pharmacist has your complete medication profile and can accurately advise you about your OTC medications.

When buying an OTC product, ask your pharmacist to check for interactions between your prescription drugs and your OTC choices. You are not being a “pest”—the pharmacist wants to help keep you safe.