Adverse Reaction vs. Side Effect: What Are the Differences? - GoodRx (2024)

When you’re diagnosed with a health condition, a treatment plan from your healthcare provider typically follows. Often, medication will play a role in this plan. But when deciding how helpful a medication may be for your treatment, many factors are considered — including the potential drawbacks.

All medications come with possible risks and side effects. Some medications may be too active in your body, leading to symptoms that range from a minor annoyance to a serious problem. Others may be too subtle, possibly leading to an ineffective treatment.

And some medications are riskier than others, and it's important to be able to identify what these risks mean for your health. These risks also have several layers, so we have terms that try to define what these differences are.

Two of these terms —adverse drug reactions (ADRs) and side effects — both describe ways a medication might affect us. And although they are often used interchangeably, they don’t share the same meaning.

Here, we’ll dive deeper into the differences between ADRs and side effects and how to reduce your risk of experiencing them.

What is a side effect?

Side effects are unintended — but predictable — symptoms that can develop while taking a medication. They can happen at normal, recommended doses, and they’re unrelated to the intended purpose of the medication.

Sometimes, side effects can have a positive health benefit. For example, some diabetes medications can cause weight loss as a side effect. But more often, they can be harmful or unpleasant. Regardless of whether these symptoms are positive or negative, they’re still considered a side effect.

If you experience a negative side effect, you may need to change how you’re taking a medication. But in many cases, if a side effect is manageable, you may be able to keep taking the medication as is.

What are some examples of a side effect?

Side effects can be a mixed bag. Not every side effect is guaranteed to happen, but some side effects are still more common than others. Some common side effects examples include:

• Drowsiness with antihistamines like diphenhydramine (Benadryl)

• Cough with blood pressure medications like lisinopril

• Weight gain with antidepressants like paroxetine (Paxil)

• Acne control with medications like spironolactone (Aldactone)

• Premature ejacul*tion control with antidepressants like sertraline (Zoloft)

What is an adverse drug reaction?

ADRs are similar to side effects, but they’re always harmful or negative. By comparison, side effects are generally bad, but they can sometimes be neutral or beneficial.

More specifically, ADRs are defined by the World Health Organization (WHO) as a response to a medication that’s harmful and unintended. They also tend to happen at normal doses and during normal use. This means that you could be taking a medication like you should and still experience a bad reaction. If you experience an ADR, you’re generally told to stop using the medication or to use a different dose.

What are some examples of an adverse drug reaction?

There are plenty of ADRs that can occur with all kinds of medications. Some of the most well-known ADRs are situations like:

• Tendon rupture from fluoroquinolone antibiotics, such as ciprofloxacin (Cipro)

• Lactic acidosis from the diabetes medication metformin

• Intense muscle breakdown after taking cholesterol-lowering medications like simvastatin (Zocor)

• Severe skin rashes from anti-seizure medications like carbamazepine (Tegretol)

Is an adverse drug reaction the same as an adverse drug event?

No, they’re not the same thing. ADRs are a type of adverse drug event (ADE).

ADEs are very general. They encompass any type of harm that’s caused by a medication. They can be preventable or non-preventable. And ADEs can happen at normal doses or at non-recommended doses. They may also happen when a medication is used as directed, or when it’s used inappropriately.

In contrast, ADRs are more specific than ADEs. They’re still harmful, but they tend to happen when a medication is used appropriately and under normal circ*mstances.

Still, neither one is desirable. But knowing the difference between them can help you better understand what you’ve experienced, and if anything could have been done to prevent it.

How can you report adverse drug reactions and side effects?

If you experience an ADR or side effect, make sure to talk to your healthcare provider. They can walk you through the situation at hand, and they can also offer suggestions to help control the symptoms that you’re experiencing.

In addition to talking to your healthcare provider, you also have the ability to report your experience to the FDA. You can do this by using the FDA’s MedWatch program. MedWatch is a safety reporting program that’s specifically designed for reporting issues with products the FDA regulates and approves. That includes drugs, biologic products, medical devices, foods, and cosmetics.

To submit a report, you have a few options. Your healthcare provider can submit a report on your behalf or you can submit it yourself. If you decide to submit a report yourself, you can submit it in three different ways:

• Online: If you have a smartphone, tablet, or laptop, you can detail your experience via an online reporting form. This is the most common way to report ADRs and side effects to the FDA.

• Paper forms: If you prefer printed documents, you can send in a physical form (like the Consumer Voluntary Reporting Form) to the FDA. You can fax it or mail it to the FDA —just make sure to follow the instructions on the form.

• Telephone: If you’d rather talk through your experience instead of trying to write it down, you can call the FDA at 1-800-332-1088 to submit a report by phone. A pharmacist there can submit a report on your behalf.

Your MedWatch report is helpful for ensuring public safety over time. The information you provide will be logged and monitored so the FDA can understand and learn about any new issues related to a medication. Because of this, it's important that you include as much detail as possible in your report.

Depending on the content and quantity of MedWatch reports that the FDA receives, they may decide to take action to protect or warn consumers about a newfound risk related to a medication, medical device, or other product.

How can you reduce your risk of experiencing side effects and adverse drug reactions?

The best thing to do to reduce your risk of experiencing ADRs and side effects is to stay involved in your healthcare journey. Asking your healthcare provider and pharmacist questions can go a long way in better understanding your health condition and the medication(s) that you take. They can help you stay informed about any potential risks or warnings you should look out for.

Make sure to also speak with your healthcare provider about your personal goals. They don’t know what you don’t tell them. Whether that relates to wanting to avoid symptoms — like weight gain, acne, or nausea — it’s helpful to communicate your preferences. This will help them make informed choices about treatment decisions that will help meet your expectations.