ISI stands for Important Safety Information, the risk disclosure that pharmaceutical companies are required to include in their advertisements for prescription drugs. It’s the block of text you see at the bottom of a print ad, the rapid voiceover at the end of a TV commercial, or the scrolling text on a website listing side effects, warnings, and contraindications. Every prescription drug ad directed at consumers or healthcare professionals must include it.
What ISI Contains
An ISI section covers the most significant risks associated with a prescription drug. This typically includes major side effects, contraindications (situations where the drug should not be used), warnings, and precautions. The goal is to give anyone seeing the ad enough risk information to balance out the benefit claims the ad is making. If a commercial tells you a drug can lower your cholesterol, the ISI is the part that tells you it may also cause muscle pain or liver problems.
The specific content of an ISI comes from the drug’s FDA-approved prescribing information, sometimes called the package insert or PI. Companies pull the most important risk details from that document and present them in a condensed format suited to the advertising medium.
Why the FDA Requires It
Federal law requires that prescription drug advertisements contain “information in brief summary relating to side effects, contraindications, and effectiveness.” This requirement comes from the Federal Food, Drug, and Cosmetic Act and is implemented through FDA regulations at 21 CFR 202.1. The underlying principle is called “fair balance”: any ad that promotes a drug’s benefits must give comparable attention to its risks.
An ad can be deemed misleading or in violation of the law if it fails to present risk information “with a prominence and readability reasonably comparable with the presentation of information relating to effectiveness of the drug.” In practical terms, a company can’t splash benefit claims across a page in large bold type while burying side effects in tiny print at the bottom. The FDA evaluates factors like typography, layout, contrast, headlines, white space, and any other technique that creates emphasis or obscures information.
How ISI Differs by Medium
The way risk information appears depends on where the ad runs. The rules vary between print, broadcast, and digital formats.
In print ads, the full risk disclosure is called the “brief summary.” Traditionally, this meant reprinting lengthy sections of the prescribing information, often filling an entire page of fine print. The FDA has recommended an alternative called the “consumer brief summary,” which presents the same risk information in plainer, more readable language rather than reproducing the clinical text verbatim.
For broadcast ads on television or radio, the rules work differently. These ads must include a “major statement” covering the drug’s most important risks in the audio portion (and for TV, in the visual portion as well). The FDA requires that in television ads, the text of the major statement uses a font size, style, and contrast that allows viewers to read it easily. Broadcast ads must also make “adequate provision” for viewers to access the full prescribing information, typically by directing them to a website, toll-free number, or print source.
Digital ads follow similar principles, though the format creates unique challenges. Scrolling ISI on branded websites, for instance, must remain accessible as users navigate the page. The same fair balance standard applies: benefit claims can’t visually or structurally overpower risk information.
ISI vs. Brief Summary vs. Major Statement
“ISI” is an industry term, not a formal regulatory one. The FDA’s regulations use more specific language. In print advertising, the required risk disclosure is the “brief summary.” In broadcast advertising, the spoken risk information is the “major statement.” When people in the pharmaceutical industry say “ISI,” they’re usually referring to whichever form of risk disclosure appears in a given ad, regardless of medium. It functions as a catch-all label for the safety information block.
The brief summary in print tends to be more comprehensive, often including the full range of side effects, drug interactions, and use-in-pregnancy warnings. The major statement in broadcast is narrower, focusing on the most clinically significant risks, because time constraints make it impractical to read every listed side effect in a 60-second commercial.
How “Safety” vs. “Risk” Framing Works
You’ll notice some ads label their disclosure “Important Safety Information” while others call it “Important Risk Information.” Research published in 2018 tested whether this framing difference affected how consumers perceived drug risks. It found no measurable difference. Whether the section was headlined with “safety” or “risk,” people interpreted the information the same way. In practice, “Important Safety Information” is the more common label across the industry.
What Happens When Companies Get It Wrong
The FDA’s Office of Prescription Drug Promotion (OPDP) monitors pharmaceutical advertising and issues warning letters when companies violate the rules. Common problems include minimizing or omitting required risk information, making the ISI less prominent than benefit claims, or leaving out contraindications entirely.
Enforcement has ramped up significantly in recent years. Over a six-month period starting in late 2024, the FDA sent thousands of letters warning pharmaceutical and telehealth companies to remove misleading ads, more than had been issued over the entire preceding decade. While many of these letters targeted specific issues like misleading claims about compounded drugs, the broader trend reflects heightened scrutiny of how drug risks are communicated to consumers across all platforms, from television to social media to telehealth websites.
For pharmaceutical companies, an OPDP warning letter can require pulling an ad campaign, issuing corrective communications, and facing reputational damage. Repeat violations can lead to more serious regulatory consequences.
Why ISI Matters in Practice
If you work in pharmaceutical marketing, medical communications, or regulatory affairs, ISI touches nearly every piece of promotional material you produce. Regulatory reviewers within a company spend significant time ensuring the ISI is accurate, complete, and presented with appropriate prominence before any ad goes live. Advertising agencies specializing in pharma build their creative around the constraint of giving risk information equal visual and verbal weight alongside benefit messaging.
For consumers, the ISI is the single most concentrated source of risk information you’ll encounter about a drug outside of a conversation with your doctor or pharmacist. It won’t tell you everything in the full prescribing information, but it covers the risks that matter most for making an informed decision about whether to ask about a medication.