Sequencing Education Center

How Long Do Side Effects Last

how long do side effects last

If you're wondering how long side effects last, you'll be happy to know they can last just a few hours. However, some people can experience side effects for much longer - days, months, or indefinitely. Why is the range so wide? It's because everyone's body is different. The way that prescription drugs and even over-the-counter medications interact with a body is influenced by many factors. 

Factors Affecting How Long Side Effects Last

factors affecting medication side effects

Most people do not know how long their side effects will last until they go through them. Constipation, dry mouth, headaches, upset stomach, and many other common side effects can greatly affect people's quality of life, though. These effects of medicine on the body can also lead to medication non-compliance and worsening of the medical condition they are meant to treat. Fortunately, knowing how long side effects last can help those suffering know what to do next. 


Taking a higher dose than needed can often lead to adverse effects. The body cannot metabolize such a high dose fast enough, so it ends up affecting a part of the body it wasn't intended to, such as the stomach. Speak to your health care professional for medical advice on if the dosage should be reduced. 

Allergic Reaction

Some people are simply allergic to an active ingredient in the medication, so the body responds undesirably. Since some allergic reactions can be life-threatening, it's essential to discuss any adverse events previously experienced with the prescribing physician. 

Medical Conditions

Suffering from some medical conditions put people at risk for drug side effects of medications for other health concerns. For instance, someone with low blood pressure may receive a medication to prevent migraines that lowers blood pressure, this may cause serious side effects. Always review your medical history with the treating physician. 

Drug Interactions

Side effects will last a very long time if the cause of them is not resolved. For instance, those who are taking other medications or supplements as part of home remedies may continue to suffer from the ill effects of their new medication because they don't interact. 

The Metabolization of the Drugs

How long it takes for the body to break down the meds matters and some people's bodies simply take longer than others. Most people will metabolize medication by half every time it circulates the body. For example, if someone takes 100 mg of a drug, only half of it will be in the bloodstream in a couple of hours. While this may seem like it would be out of a person's body quickly, the rate of it being broken down is much slower afterward. Only 10 mg may be excreted by the body the next time it goes through the liver, and possibly only 5 mg the next pass.


Weight influences how fast medication breaks down in the body, so it also affects how long side effects will last. Usually, but not always, the bigger people are the slower it takes for drugs to break down and leave the body. 


People from different ethnic backgrounds process medications differently. This is why family members often have the same issues with drugs as others in their family. 

The factors influencing how long side effects last may not provide the answer most are looking for, but it does explain why some people can't take certain medications because the side effects are unbearable. 


Serious side effects should be reported to a physician and/or PharmD for medical advice. The National Institute of Health (NIH) and the U.S. Food and Drug Administration (FDA) monitor the side effects of new and approved medications to ensure safety. However, since people's bodies react so differently to drugs, they often have to change their stance on certain drugs. This is why they have a program called MedWatch that encourages Americans to report adverse reactions.


Learn More: How Long Do Side Effects Last

How Side Effects Affect Treatment

Many people suffering from depression have a difficult time finding the right treatment. Antidepressants are notorious for having many potential side effects. Possible side effects such as unexplained weight gain, weight loss, and suicidal ideation can make the mental health issue worse. This is why many people are starting to seek genetic testing to identify the best medications for their medical and mental health concerns. 

Learn More: What to Do When Medicines Have Side Effects

DNA Testing to Prevent Side Effects


DNA testing can help people avoid side effects. The information derived from the test can be analyzed to show which medications are best for the person along with the right dosage. The study of pharmacogenomics has made this possible, and the use of it is increasing in popularity. Doctors worldwide are now using the information to prescribe medications because it saves time, money, and a lot of discomfort for patients. 

Medication and Drug Response Advanced Pharmacogenomics Analysis offers a Medication & Drug Response DNA Report that includes information about your risk of side effects with common medication, how to reduce side effects of medicine, as well as your risk of addiction to certain medications and illicit drugs.

Those who have already had a DNA test by 23andMe, AncestryDNA, MyHeritage, FamilyTreeDNA, and Dante Labs can upload their raw DNA data easily to's secure and confidential account. Our Privacy First commitment ensures your data remains private. We never sell or share your data, including your DNA data, with anyone. 

Upload DNA Data  

For those who have not yet taken a DNA test and don’t have raw DNA to upload, you can purchase a DNA test kit online. Once the DNA test has completed, your DNA data will be stored in your confidential account and ready to use with the Medication & Drug Response DNA analysis app or another report from the wide assortment available from 

Order DNA Kits