Through its Drug Search tool, RxISK provides a list of the top 100 side effects of a prescription drug that were reported to the FDA (Food and Drug Administration) in the United States, that you can review before getting your prescription filled to help you make an informed choice about use.
When consumers (parents, guardians or caregivers) research a drug, RxISK also provides access to medication guides, prescribing information, and RxISK Reports from people trying to find out if a problem was caused by a drug side effect.
It is also important to be aware of possible drug interactions before you start taking a drug, and that the risk of adverse reactions might increase if you are on multiple medications. Drugs.com has developed a Drug Interactions Checker that might be helpful.
Government Warnings
When prescription drugs are first approved by government regulators, the approval is based on scientific evidence of safety and effectiveness from at least two clinical trials that pharmaceutical companies share with the regulator. In some cases, companies fraudulently conceal negative clinical trial data to get drugs approved (e.g., GlaxoSmithKline: concealed cancer-causing contaminants in Zantac to get it approved by the FDA in 1983 for treating heartburn).
It often takes many years for governments to receive enough reports from post-marketing experiences to publish warnings about serious side effects. Many of the warnings are only distributed to healthcare professionals.
Here are some warnings from the FDA in the United States and Health Canada about serious side effects of several types of prescription drugs, and what they are commonly prescribed for (in brackets).
Antidepressants (depression and anxiety)
Benzodiazepines (anxiety)
Opioids (pain)
Statins (high cholesterol)
Stimulants (ADHD)
Here is a list of Recalls and Safety Alerts from the FDA