Understanding the risks in clinical trials

Side effects

Treatments can cause side effects, ranging from mild (headache, nausea, or soreness at an injection site) to rare but serious (allergic reactions or organ effects).

Placebo

Some trials compare a potential treatment with a placebo (inactive pill or shot). Participants receiving a placebo may not experience improvement in their condition.

Unknown risks

Some risks may not be known yet, which is why careful monitoring is important.

Finding information about risks

Understanding where to find information about risks helps participants make informed decisions and get answers whenever questions come up.

• Informed consent document: Explains the trial’s purpose, procedures, known risks, and what to do if problems occur.
• Public registries and trial summaries: Sites like clinicaltrials.gov provide details about the purpose of the trial, what’s being tested, and safety monitoring plans.
• Healthcare providers: A trusted source to review potential risks and discuss safety measures.

What to do if symptoms occur

• Know who to contact: The informed consent document provides contact information for the research team, including a doctor or coordinator, and emergency instructions. Always keep your healthcare provider informed.
• Document symptoms: Track when symptoms start, severity, and any changes.
• Medical follow-up: The clinical trial team may review symptoms, examine participants, and make changes if needed. All side effects are carefully documented to protect participants and improve safety for everyone.

What happens if a clinical trial is found to be unsafe?

If safety concerns come up, a few things happen:

• Suspension or termination. A trial can be paused then resumed when changes are made. Or the clinical trial can be stopped entirely if the oversight groups and ethics committee find that the risks of the trial outweigh the potential benefits.
• You’ll be informed why the trial was paused or stopped and what it means for your care.
• You may be asked to stop the potential treatment provided by the study and return for safety visits. Tell your primary care doctor about any changes so they can manage your medical care accordingly.