When your medicine comes with a long list of side effects

“I will never get anywhere near that medication,” my patient announced soon into our last visit. We were discussing a medicine I wanted to prescribe to help him stop smoking. He had tried a different medicine for this a few months earlier and stopped taking it, after experiencing the unpleasant side effects of nausea and fatigue.

Now, seeing nausea and fatigue on an online list of side effects of the new medicine, he decided this medication was not for him either. He wouldn’t even try it.

If you take any prescription medication, this scenario may sound familiar. It can be scary to look at a long published list of side effects; perhaps they have made you hesitate about taking or avoid filling your own prescription. It helps to take a closer look at what the term side effects means and how published lists of side effects are created.

You might think of side effects like you do side dishes — things that you can expect will always happen, like side dishes that always accompany the main course. In fact, side effects are things that might happen but usually do not. Further, most medication side effects are mild annoyances that will go away quickly after you stop the medicine.

And it is equally important to consider the consequences of not taking a prescribed medicine. The medical problem or health risk the medicine is meant to address could become a much greater threat to your well-being than a possible minor drug side effect. My patient who smoked, for example, faced potential consequences from not quitting such as lung cancer, obstructive lung disease, heart disease, and stroke.

» READ MORE: Why a Penn Medicine doctor tells patients struggling to quit nicotine, 'It's not your fault.'

Some medications (relatively few) have side effects that are serious enough to warrant a black box warning. This is a label placed on prescription drugs when there is risk of serious harm. These medications require especially careful consideration and discussion with your doctor before taking.

Even these black box side effects are unlikely, but when they do occur, the consequences can be more severe or even life threatening. Black box labels may appear on a medicine when it is first introduced or if new information comes to light after marketing, so it is important to ask your doctor if any new warnings have been issued for medicines you are already taking.

Part of the confusion and anxiety around medication side effects stems from the way they are reported and published. The Food and Drug Administration (FDA) requires that pharmaceutical companies report all side effects associated with use of a medication during development, testing, and after marketing.

When a new drug is being tested in clinical trials, patients taking the medication are monitored closely and compared to a placebo group — people who are unaware they are taking an inactive, “fake” form of the drug. When a side effect occurs significantly more often in the group taking the actual drug, it is easy to conclude that it is being caused by the drug.

After marketing, many more people will use a drug in the “real world” than during the trial period, and monitoring continues for side effects that were not detected during a clinical trial. Here’s the problem: there is no placebo group out in the real world, making it hard to tell if a side effect is actually caused by the drug or is just coincidence.

Many of the side effects listed on websites and advertisements have been reported by patients or health-care providers after marketing, and their significance is uncertain. Your doctor can help you sort these out and decide if you should be concerned.

I helped my patient understand that nausea and fatigue are quite common symptoms that show up on many potential side effect lists. The fact that he experienced them with one drug does not mean he is more likely to have the same symptoms with a completely different drug. He said he would give this some thought and reconsider taking the medication.

Closely watching for possible side effects of medications is important for drug safety, and we are fortunate to have a robust monitoring system here in the U.S. But this careful process generates its own side effect — an abundance of information in print and online — which can be overwhelming to review and understand.

Don’t go it alone; talk with or message your medical care team, which may include your doctor, advanced practice provider, pharmacist, and nurse. Be sure you feel comfortable with the explanation you receive. And “don’t worry about it” should never suffice.

Jeffrey Millstein is an internist and regional medical director for Penn Primary Care.