Reading a reaction list

Every drug page carries a ranked list of the MedDRA terms recorded in that drug's reports, each with a solid bar and a hollow bar. This guide explains what the pieces are.

The term

MedDRA is the dictionary FDA and manufacturers use to code what a reporter described. "Dyspnoea" is the preferred term a coder chose for a description of breathlessness; "Drug ineffective" for a report that the medicine did not do what was expected; "Off label use" for a report that the drug was used outside its labelled indication. Some frequent terms describe circumstances rather than harm, and some (such as the indication being treated) appear because the coder recorded the condition itself. The short gloss beneath a term is this site's plain-language dictionary entry; it adds nothing to the report.

The share

The percentage is the share of the drug's reports that record the term. Because a report can record several terms, shares add to more than 100%. A share is a share of reports, not of patients: it says how often the term appears among the people who reported, and nothing about how often it occurs among the people who take the drug, whose number is not in the data.

The hollow bar

The hollow bar is the median share of the same term across the drugs in the same pharmacologic class (or, where no class is known, the term's share across the whole database). It gives a number something to be read against. A share above the median means the term is recorded more often in this drug's reports than in the typical member's; reasons include the condition being treated, the people who take it, its time on the market and how its reports are collected, as well as anything about the drug itself. FDA's statement applies: a causal relationship cannot be established from a report.

What the list cannot say

• It is not a list of the drug's side effects. The adverse reactions observed in clinical studies are printed on the FDA-approved label.
• It cannot rank products. FDA states that "common products may have a higher number of adverse events due to the higher total number of people using the product" and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
• It cannot tell an individual what to expect. A pharmacist or clinician who knows the patient can.