What Side Effects Commonly Occur with Non‑Stimulants?

PostedSeptember 22, 2025

UpdatedSeptember 22, 2025

ByMy Patient Advice

Author: Avery Lombardi, MSc | Reviewed by: Dr. Rebecca Fernandez, MBBS

Non-stimulant ADHD medication side effects are generally less pronounced than those associated with stimulants, but they can still occur. Medications like Strattera (atomoxetine) and Intuniv (guanfacine) offer a gentler approach to managing ADHD symptoms, but they come with their own set of potential side effects.

Fatigue

One of the most common non-stimulant ADHD medication side effects is fatigue. Medications like Intuniv can have a calming effect, which may lead to drowsiness or tiredness, especially when first starting treatment or adjusting the dosage. This can be particularly noticeable in the first few weeks of use. For individuals taking non-stimulants, it’s important to monitor how tiredness affects daily activities and discuss dosage adjustments with a healthcare provider if necessary.

Stomach Upset

Stomach upset is another frequent side effect of non-stimulant ADHD medications, especially with Strattera. Some individuals may experience nausea, decreased appetite, or mild stomach pain. These side effects typically improve over time, but they can be managed by taking the medication with food or adjusting the dosage as recommended by a healthcare provider.

Other Side Effects

Less common but possible side effects include headaches, irritability, and sleep disturbances. While non-stimulants generally have a milder side effect profile than stimulants, individuals may still experience mood changes or difficulty sleeping, especially when the medication is first introduced.

In conclusion, while non-stimulant ADHD medication side effects like fatigue and stomach upset are common, they are usually mild and manageable. If side effects persist or interfere with daily life, it’s important to consult with a healthcare provider for potential adjustments to the treatment plan.

Visit providers like ADHD Certify for personal consultations and expert guidance tailored to your unique situation.

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to Medications for ADHD.

Avery Lombardi, MSc

Author

Avery Lombardi is a clinical psychologist with a Master’s in Clinical Psychology and a Bachelor’s in Psychology. She has professional experience in psychological assessment, evidence-based therapy, and research, working with both child and adult populations. Avery has provided clinical services in hospital, educational, and community settings, delivering interventions such as CBT, DBT, and tailored treatment plans for conditions including anxiety, depression, and developmental disorders. She has also contributed to research on self-stigma, self-esteem, and medication adherence in psychotic patients, and has created educational content on ADHD, treatment options, and daily coping strategies.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy.

Dr. Rebecca Fernandez, MBBS

Reviewer

Dr. Rebecca Fernandez is a UK-trained physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence-based approaches such as CBT, ACT, and mindfulness-based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewer's privacy.