Finding out about the side effects of your prescription drugs

Here’s how to locate the information— and how to make sense of what you find.

(This article was first printed in the April 2005 issue of the Harvard Health Letter. For more information or to order, please go to http://www.health.harvard.edu/health.)

These days, many people are jittery about the side effects of prescription drugs. But how do you find out about the hazards of your medications? Sometimes the information just isn’t available — for the wrong reasons. We’ve been hearing a lot about cases in which drug companies kept negative clinical trial results under wraps. In some cases, there may also be an element of legitimate doubt and debate.

But in many instances, information about side effects is available; it just doesn’t seem to be getting through very well. So if you have concerns, you’ll need to take the initiative in getting answers. At the same time, it’s important to keep things in perspective. Usually serious effects are rare events. You should know about them, but a fear of side effects shouldn’t keep you from taking medications that you need.

Here’s a guide to sources of information on drug hazards and side effects, and some pointers on how to make sense of what you find.

The package insert

The FDA-mandated package insert — printed in plain black type on both sides of a folded sheet of white paper — provides extensive drug information for physicians and pharmacists. News accounts and other sources may mention a drug’s “label” or “warning label.” That’s just shorthand for the package insert and does not refer to an actual label on the bottle.

If your medication comes in the manufacturer’s original packaging (an asthma inhaler in its box, for example), the package insert will be included. For prescriptions filled from bulk pharmacy supplies, you won’t get a package insert unless the pharmacist adds one, because the bulk bottle comes with just one insert meant for the pharmacist. You can find the same information in the Physician’s Desk Reference (PDR), a massive compilation that includes every prescription drug package insert. The book costs about $35 and is updated every year. You should be able to find a PDR in the reference section of your library.

If you decide to consult the package insert (or the PDR) it helps to know how the information is organized. Package inserts follow a standard format, explaining the drug’s chemical makeup, its mechanism of action, when (and when not) to use it, whether it carries a risk of dependence or abuse, dosage information, and hazards and side effects. Specific headings to consult on side effects are:

• Contraindications (explains when a patient should not receive a drug)
• Warnings (describes serious side effects and potential safety hazards)
• Precautions (includes drug interactions)
• Adverse Reactions (provides a comprehensive list of side effects).

For the most serious problems — involving a risk of death or serious injury — the FDA may require a boxed warning, commonly called a “black box warning.” This notice is placed in a black outline box, often at the top of the insert, and it is sometimes printed in boldface type.

Problems with the package insert

You may want to have a magnifying glass handy:The tiny type used in the insert is aggressively resistant to consumer inquiry. Another problem is the way it’s written — in arcane medical language and a format specified by federal regulations. The result: a train wreck of science and law, created largely by committee.

The package insert’s catalog of side effects is hard to assess. “Adverse Reactions” includes every side effect reported during the drug’s clinical testing, and, when appropriate, the side effects of other drugs in the same class. Potentially fatal adverse reactions may also be listed under “Warnings” or “Contraindications,” or in a black box.

The result can be information overload. For example, under “Adverse Reactions,” the package insert for the sleeping pill eszopiclone (Lunesta) contains two tables of side effects — one for elderly patients (13 side effects noted during a two-week clinical trial) and one for younger adults (19 side effects noted during a six-week clinical trial). Six of these side effects appear on both tables. Then there’s a list of 127 more side effects “observed during premarketing evaluation,” which range from “abnormal gait” to “vestibular disorder.” Such a laundry list obscures more than it informs.

If you do consult the package insert, have a good dictionary handy, preferably a medical dictionary. You might also check an online medical dictionary, like the one at MedlinePlus — a Web site sponsored by the National Institutes of Health (NIH) and the U.S. National Library of Medicine (see www.nlm.nih.gov/medlineplus/encyclopedia.html).

Other sources of information

FDA-mandated patient information. For some prescription medications, the FDA requires information sheets designed for patients. They’re written in plain English and are much more straightforward than the package insert. For example, information aimed at health professionals warns that the antidepressant nefazodone (Serzone) carries a risk of “life-threatening hepatic failure” and “hepatotoxicity.” The patient information refers to “serious liver problems.”

At one time, the goal was to have such information available for all drugs, but now the government requires it for only a few. According to Dr. Jerry Avorn, a professor at Harvard Medical School and author of Powerful Medicines: The Benefits, Risks, and Costs of Prescription Drugs (Knopf, 2004), the FDA has developed these printed patient medication guides for only about 15 drugs. “The current view in the federal government is that the FDA shouldn’t regulate consumer drug information,” he says.

Drug information from your pharmacy. When you fill a prescription, the pharmacy will probably give you a drug fact sheet. CVS, Walgreens, and other pharmacies provide these printouts, which are developed by private companies, with every prescription they fill. They’re far easier to understand than the package inserts, but Dr. Avorn says the information in them is “very spotty.”

As of April 2005, the FDA has no power to regulate drug information provided by pharmacies. In 2003, the Public Citizen’s Health Research Group analyzed printouts distributed in a Washington, D.C., pharmacy. Focusing on 23 top-selling drugs that carry “black box warnings,” it found significant variability and shortcomings in the information provided.

Online sources of information.You can also find out about drug hazards and side effects through various Web-based resources. All have limitations, but they are good places to start.

(This article was first printed in the April 2005 issue of the Harvard Health Letter. For more information or to order, please go to http://www.health.harvard.edu/health.)

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