On Jan. 22, 2009, actor Heath Ledger -- young, talented, and presumably healthy -- was found dead in a New York apartment. A few days later, law enforcement officials announced he was a not victim of foul play or lethal street drugs like cocaine or heroin. He didn’t commit suicide, either. Instead, he accidentally took a deadly combination of six prescription medications. Legal drugs also played a role in the untimely deaths of many other celebrities, including Anna Nicole Smith, DJ AM, Michael Jackson, and Elvis Presley.

But if you think stars who lead lives of excess are more likely to succumb to an unfortunate drug-laced ending than the rest of us, think again. According to the Centers for Disease Control and Prevention (CDC), prescription drugs cause the deaths of about 40,000 Americans each year.

Sure, some people abuse drugs until they suffer organ failure, others use drugs to commit suicide and, rarely, some have fatal allergic reactions to meds. But tens of thousands of people die from unintentional and unnecessary medication accidents because they assume it’s OK to increase a dosage or combine drugs without realizing the toxicity involved.

Bottom line: prescription drugs that are usually safe when taken properly can make you sick and even kill if mixed or taken in the wrong amount. "It’s a huge problem. Pharmacists work every day to prevent those accidents from happening," says Amir Emamifar, Pharm D, director of Pharmaceutical Services for Emory Healthcare in Atlanta.

Combining meds on your own: a prescription for danger

For several months, you’ve taken a prescription drug for your hypertension with no problem. Then you pull a shoulder muscle and remember you still have some pain relievers your doctor prescribed a year ago. You aren’t allergic to them and the pills helped before, so why not take them now? The combo may be perfectly fine -- but you could also be playing Russian roulette with your health if you don’t clear the mix of drugs with your physician or pharmacist before you pop those pills.

"Every drug has some kind of interaction with something and some kind of side effect. But pharmacists can’t help people if we don’t know what people are taking," says Emamifar.

In fact, if Heath Ledger had checked with a pharmacist about the safety of taking several prescription drugs together, he’d probably still be alive. The New York Medical examiner ruled the movie star "died as the result of acute intoxication by the combined effects of oxycodone, hydrocodone, diazepam, temazepam, alprazolam, and doxylamine." Specifically, the autopsy report showed the mix caused his central nervous system to slow down so much his heart stopped beating, he quit breathing, and never woke up.

But you can be in danger without using a half dozen different medications at one time like Ledger did. What’s more, over-the-counter (OTC) medications can’t automatically be assumed as safe to take with other drugs, either. And while some med combinations aren’t necessarily life-threatening, they’re still dangerous, combining synergistically to increase or decrease potency and cause potentially dangerous side effects.

Here are some examples provided by Sally Huston, Ph.D., assistant professor of Clinical and Administrative Pharmacy at the University of Georgia (UGA) College of Pharmacy in Athens:

• Are you taking birth control pills? Antibiotics can lower the effectiveness of these contraceptives, resulting in an unwanted pregnancy.
• Warfarin (also known under the brand names Coumadin, Jantoven, Marevan, Lawarin, and Waran) is the most widely prescribed anticoagulant drug in North America. It’s an effective, relatively safe medication for preventing blood clots. But if you’re on this drug and decide to also take aspirins for a headache, you could end up with a bleeding ulcer -- potentially, a very serious situation if not detected and treated quickly.
• Benzodiazepines (like Xanax, Valium, Klonopin, and Librium) comprise a class of drugs used to treat problems such as panic attacks, seizures, and muscle spasms. Combine Valium drugs with the heartburn treatment omeprazole -- a popular proton pump inhibitor (PPI) sold in prescription strength and over-the-counter as Pepcid -- and blood levels of benzodiazepine could soar, causing an overdose. Taking the antibiotic clarithromycin also increases the risk of toxicity from benzodiazepines.
• Statin drugs reduce elevated cholesterol but sometimes cause myopathy (muscle inflammation). If you take gemfibrozil (sold as Lopid), a fibrate drug often used to reduce triglycerides, with a statin you increase the odds for this side effect. "Myopathy doesn't always have symptoms, and in very rare cases could lead to kidney failure and death," says Dr. Huston.

Changing doses and other self-medication dangers

UGA professor of clinical and administrative pharmacy Randall L. Tackette, Ph.D, points out how self-medicating -- including adjusting your own dosage and combining drugs with alcohol (which is, by the way, a drug) -- can be a dangerous practice. One common mistake: combining pain pills like narcotic-containing Lortabs, OxyContin, Percocet, and Vicodin with alcohol or sleep medications such as Ambien or benzodiazepines.

"Although many times these drugs may be prescribed together, you can have a really bad interaction -- especially if you take them with alcohol or even take just a bit more than you should, " Tackette warns. "For example, a person may have a sore back. Percocet is helping so he overdoes yard work, then his back hurts more. So he bumps up the dose and takes two Percocets. Maybe he can’t sleep from the back pain so he takes an Ambien or has a beer. This is the kind of situation that leads to overdosing."

It’s also not unusual for people taking non-narcotic pain relievers such as tramadol (Ultram) to think they can take more than the amount prescribed. "It’s not listed as a narcotic, so people will think it is extremely safe and will take too many and overdose," Tackette says.

He adds that when people are on prescription pain relievers for months to years for chronic problems, a tolerance can develop and dosages can be safely increased, under your physician’s guidance. However, once you stop taking the drug, you may not realize that your tolerance to it has gone back down. Then, if pain returns and you reach for your pills again, taking the same dosage you were on when your tolerance to the medication was high could result in an overdose.

Another common and risky practice is borrowing prescription drugs. "We see a lot of geriatric patients on fixed incomes do this. Someone will have similar symptoms to a friend who has a prescription for what seems to be the same condition, so they will swap drugs with no consideration of drug dosage or interaction with other meds," Tackette says.

It’s also common for people to ignore or misunderstand the instructions, "do not take with alcohol." Too often, it’s assumed to just mean "don’t swallow your pills with booze."

"But a person may have a few drinks, wait hours later, and then take their medication, not realizing residual alcohol is still in the body," Tackette emphasizes. "In some cases it is better to not drink at all while on medication. We generally tell people if they are going to drink, be aware it will cause greater impairment because of the medication. So don’t drive." Prescription and OTC antihistamines like Benadryl, and even some drugs advertised as "non-sedating," can make you too drowsy to drive safely, as well.

Natural doesn’t always mean safe

People often assume that supplements or herbal products are safe to add to your medication regime. However, being labeled "natural" doesn’t mean a product can’t cause serious consequences when combined with drugs.

"After all, a majority of drugs, especially older cardiovascular drugs like digitalis, were derived from plants. Herbal products can have numerous effects, and combining them with certain medications can be disastrous," says Emory’s Emamifar. "For example, if you are taking the herb St. John’s wort, commonly used for depression, and you have an operation in which the anesthesia propofol is used, you could suffer cardiovascular collapse."

Even taking an herbal product containing garlic can increase bleeding time if you are on an anticoagulation medication. The herbs kava and valerian root have tranquilizer-like effects and can interact with benzodiazepines.

Another issue with natural products: the potency, dosage, and purity of ingredients can vary widely. In fact, a number of supplements were pulled off the market in the past few years when they were found to be adulterated with drugs, notably Viagra.

Your prescription for medication safety

How can you make sure any prescription or OTC drug combinations are safe -- and know if it’s OK to take herbs or other supplements with your medications? One way to keep a handle on the drugs you take and possible interactions is to deal with one pharmacy, where all your medication records are on file. "Patients are unaware that the use of multiple pharmacies increases risk because multiple pharmacists can’t effectively monitor for the presence of drug interactions, "says Michael W. Neville, Pharm.D., clinical associate professor at UGA’s College of Pharmacy.

More tips for medication safety:

• Be honest with your doctors and your pharmacist. List all the drugs and supplements you take. And don’t forget any drug samples you may have received from your physician.
• The most likely time for adverse drug effects to occur is within the first few days of a medication change when a new drug is added or one is stopped. If any new symptom develops, call your pharmacist or doctor.
• Your pharmacist may be busy but don’t just sign for your prescription and rush out the door. Make sure you understand how to take your drug safely and wait until your questions have been answered before taking a medication. "Any time a new prescription is filled, ask the pharmacist to verify that there are no drug-to-drug interactions," says Neville.
• Obtaining medication refills? Neville advises opening all your prescription bottles at the pharmacy counter or drive-in. Yes, pharmacists can make mistakes. Make sure all the tablets or capsules inside look familiar to reduce the likelihood of an incorrectly filled medication.
• Keep an up-to-date list of all the medications and supplements you take. Print them on a card or piece of paper and carry them in your wallet along with your driver’s license. You can also ask your pharmacist for a print-out of your medications. The reason? If you are ever in an emergency situation and unable to provide your drug history to medical personnel, they can quickly find the information needed to treat you as safely and quickly as possible.

Sherry Baker is a writer from Atlanta, Georgia. She last wrote "Halloween Office Party Tips" for Synergy. Sherry can be reached at featuredstories@adamcorp.com.