December 1, 2011

Dying from the Common Cold

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“Let’s see how you like THIS,” I thought to myself, tossing a bottle of cough suppressant into my cart. I was going to make this cold virus pay. How dare it try to mess with me this week, of all weeks during the semester? With two prelims and a paper due within a matter of days, this evil virus had some nerve!

Deep down, I knew there was no way I was going to get rid of this cold, no matter how many medicines I took. There was no cure for the common cold and no vaccine to prevent this annoyance. I saw it as some necessary toll to pay each year. In order to “Pass Go” to make it to the spring, I had to suffer through an inevitable week of sore throat and clogged sinuses, and another two weeks of maddening cough that always seemed determined to embarrass me during lectures.

But I couldn’t afford to pay the toll this time, and I wouldn’t listen to reason. “Let’s see … NyQuil for night, DayQuil for day. Sudafed, I think that is supposed to help …” I felt a sense of entitlement to feel better. Instead of getting a good night sleep, I had spent the night gagging on the waterfall of mucus pouring down my throat. Even if I couldn’t kill the virus, I was sure as hell was going to try to cut off its attack plan at every turn.

Rationally, I knew there was probably a redundancy in the drugs I haphazardly threw into my cart, but I felt there couldn’t be any harm. After all, these were just over-the-counter medicines. I figured they must be idiot-proof, and here I was an Ivy League Cornell medical student. Somehow I equated my presumed intelligence with invincibility.

Thankfully, my pharmaceutical frenzy did not result in a trip to the emergency room. The worst I had to pay for my idiocy was horrible abdominal pain and diarrhea that conveniently decided to strike during one of my prelims. Looking back on the experience though, I consider myself to be lucky. In my attempt to play doctor, I was really playing with fire.

As I have come to learn in medical school, over-the-counter drugs can be extremely dangerous.  Reading the label and understanding the actual ingredients is much more important than the brand name of a drug. This isn’t like reading the obscure list of chemicals on a soft drink can. Knowing whether or not a medication contains, for example, acetaminophen is actually extremely important and can mean the difference between life and death.

The example mentioned above, acetaminophen, is best known as the active ingredient in Tylenol and is one of the most commonly used medicines for controlling pain and fever. While its complete mechanism of action is not completely understood, it is thought to act primarily in the brain by inhibiting an enzyme called cyclooxygenase, which ordinarily produces inflammatory molecules. Under normal circumstances, acetaminophen is safely cleared from the body by the liver through several pathways, but in the process of getting broken down, an intermediate is formed, called N-acetyl-p-benzoquinone imine, or NAPQI. This molecule is toxic to the liver, and in fact, in the developed world, acetaminophen poisoning is the leading cause of acute liver failure. In the United States, acetaminophen accounts for more deaths annually than any other pharmaceutical drug.

While the exact level needed for toxicity is subject to individual variability, acetaminophen is normally considered to be safe at a daily dose of less than four grams. Consider, though, that a single Extra Strength Tylenol caplet contains 500 milligrams, or one-eighth this amount. Furthermore, many other medications inconspicuously happen to contain high doses of acetaminophen. For example, prescription pain medications such as Vicodin or Percocet contain acetaminophen along with an opioid (narcotic) constituent. Many cold relief medications such as NyQuil or Coricidin HBP contain acetaminophen as one of the active ingredients. Confusing matters further, brand names might contain special suffixes, secretly indicating that additional compounds have been added to the formula. For example, while regular Benadryl is just a single chemical called diphenhydramine, Benadryl Cold & Allergy actually contains acetaminophen, along with other active ingredients.

Without a sharp eye and keen awareness, it is easy to see how someone might inadvertently overdose on an over-the-counter medication such as acetaminophen. Exacerbating matters even more, the threshold for toxicity can be lowered by using other drugs, and possibly by consuming alcohol.

It is also important to recognize that acetaminophen is certainly not the only over-the-counter drug that can be dangerous in excess. The gastrointestinal symptoms I experienced were likely a mild side effect of several ingredients in the cold medicines. However, overdose of these substances, such as dextromethorphan, diphenhydramine and pseudoephedrine, can lead to serious and life-threatening complications as well.

I’m not trying to say that all over-the-counter drugs should be banned or labeled with a giant skull-and-crossbones. The truth is that over-the-counter drugs are usually safe when taken at the appropriate doses. In fact, the process for a prescription drug to become over-the-counter can take several years and involves intense review of consumer safety data by the FDA and several other government bodies. Nevertheless, it is still a good idea to talk to a doctor about trying new drugs, especially if you have a medical condition or are taking other medications. Be a smart consumer and actually read the labels on the bottles to understand what you are putting in your body. Don’t assume that more is better, as all drugs come with side-effects that might actually make you feel worse. Lastly, even though there is no cure for the common cold, to the best of my knowledge, no one has ever overdosed on simple rest and chicken soup.

Eric Heintz graduated from Cornell in 2006 and is a fourth-year medical student at Weill Cornell Medical College in New York City. He may be reached at What’s Up, Doc? appears alternate Fridays this semester.

Original Author: Eric Heintz