Could you choose the best prescription drug to prevent a heart attack or to treat heartburn? A study shows that if printed drug advertisements contained a short "fact box," you'd be much more likely to choose wisely.

But in order to weigh the importance of the side effects, you need to know the benefits.

Drug advertisements rarely tell how well a drug works. They don't do a good job of explaining drug side effects, either. What's the simplest way to change this? Add a short fact box that contains both a simple description of what the drug is for and a short table that numerically shows the drug's effectiveness and most common side effects.

Currently, the FDA requires drug advertisements to list the risks associated with a drug in a "brief summary" but not the benefits. But in order to weigh the importance of the side effects, you need to know the benefits.

A team at Dartmouth Medical School conducted two trials to test the effect of replacing the brief summary with a fact box. One trial compared ads for two heartburn medications; the other compared ads for two cardiovascular drugs.

Not only did people like the drug fact boxes, they understood them. When asked to choose between two heartburn medications, subjects given the ads with fact boxes picked the drug currently regarded as superior more than twice as often as subjects given the conventional advertisements did. When given ads for two cardiovascular medications, subjects shown the ads with fact boxes were eight times more likely to correctly describe how much each medication lowered the risk of heart attack.

Some might say that this only proves the obvious: the people who saw the fact boxes were given the "right answers." But that's the goal of the fact box — to give people the information needed to make reasonable decisions. Without this information, people can only guess at a drug's effectiveness.

Will fact boxes be required in drug ads anytime soon? The researchers don't know. They certainly hope so.

The trials were of prescription drugs: medications people can only buy with a doctor's prescription. They're still relevant because there are studies which show that doctors will often prescribe medications to patients who express an interest in them. Fact boxes should lead to more meaningful doctor−patient discussions about which drug is best for a particular condition, rather than having patients ask for a drug based on vague claims made in an advertisement.

The studies were performed on adults aged 35−70. There were 231 participants in the heartburn medication study and 219 participants in the cardiovascular drug study. Subjects were given printed advertisements for two medications. One group received ads containing the conventional brief summaries; the other, ads with fact boxes. Both groups were then asked to answer various questions about the medications' effectiveness, side effects and which medication was the better choice. Responses were submitted by mail.

The study results were published in the February 17, 2009 online edition of Annals of Internal Medicine.