The Food and Drug Administration (FDA) is the government agency responsible for ensuring that medicines and medical devices work, and they are acceptably safe.
Any drug may produce unwanted or unexpected side effects (also known as an adverse event).
Many side effects are linked to the way the drugs work to treat a patient. For instance, medicines known as beta-blockers treat high blood pressure by acting on particular sites in the muscles of blood vessels, causing the muscles to relax, reducing blood pressure. The medicine, however, also acts on sites in the heart, which may cause a side effect in some patients where their heart beat is slowed down.
Some side effects, however, are not linked in this way and can be unpredictable. As individuals, different patients may respond in different ways to the same drug. For this reason, it is often difficult to predict how different patients will respond to a medicine, including whether they will experience any side effects.
Before a medicine is licensed, it will be tested in a series of clinical trials. Such trials are carried out in a relatively small number of patients - on average 1,500 for a new medicine. In addition, clinical trials are conducted under very strict conditions. In everyday life, medicines will not be used under trial conditions and may be used by millions of patients across a range of age groups, who may also be taking other medicines and who have varied lifestyles.
Although clinical trials are generally able to identify the more common and predictable side effects of medicines, rarer side effects may only be highlighted once the medicine is used by a far greater number of patients under the conditions of every day use. In addition, some side effects may not be discovered until many people have used the medicine over a period of time. Side effects can also occasionally appear after stopping a medicine.
No effective drug is completely free of side effects, however, most side effects are relatively uncommon. In general, the majority of people who take a particular drug do not experience any serious side effects. Even side effects that are described as common may only occur in a few people in every 100 who take the drug.
When you decide with your doctor that you should take a medicine, you should consider not only the risk that you may possibly experience a side effect, but also the benefit that you will gain from the medicine, and the risks of not treating the condition. For instance, if you are taking a medicine to treat a life threatening illness, you might be more willing to accept the possibility of more serious side effects than if you are simply treating a cold or a headache.
FAERS data do have limitations. First, there is no certainty that the reported event was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event. Further, FDA does not receive all adverse event reports that occur with a product. Many factors can influence whether or not an event will be reported, such as the time a product has been marketed and publicity about an event. Therefore, FAERS cannot be used to calculate the incidence of an adverse event in the U.S. population.
The data comes from the Food and Drug Administrations (FDA) Adverse Event Reporting System (FAERS). FAERS is a database used by the FDA to monitor all approved drug and therapeutic biologic products. The FDA uses FAERS to monitor for new adverse events and medication errors that might occur with these marketed products.
Drugcite uses a series of algorithms to clean FAERS data, removing duplicate entries and entries with malformed data. DrugCite then takes your query and expands it to include generic drugs and other brand name drugs containing the same primary active ingredients. If you query Lipitor, DrugCite will use medical dictionaries to expand your query to include Atorvastatin, the generic name for Lipitor. If you query Atorvastatin, DrugCite will include adverse events reported for Lipitor. In cases where a generic drug has many brand names, such as Hydrocodone, DrugCite will only expand the query to include up to 100 brand names. If you search Adderall, you will receive more results than if you search Adderall XR 30.
Depending on how the data is aggregated, different counts may occur. When someone submits an adverse event to the FDA, the submitter can attribute multiple adverse events to one or more drugs. For example, an individual taking Paxil could submit the adverse events "anxiety" and "suicidal ideation" for the same individual safety report (ISR). This means when DrugCite aggregates by adverse event, two distinct adverse events are counted in the adverse event graph; once for "anxiety" and again for "suicidal ideation". However, when DrugCite aggregates by individual safety reports irrespective of the details of the adverse events contained within the safety report, the report is only counted once.