Atomoxetine Drug Interactions

Atomoxetine (brand name Strattera) can interact with other medications in ways that may reduce its effectiveness or cause dangerous side effects. Knowing what to avoid — and what to tell your doctor — is essential for safe treatment.

This guide covers the most important drug interactions, including prescription medications, supplements, over-the-counter drugs, and food or drink considerations.

How Drug Interactions Work

Drug interactions happen when one substance changes how another works in your body. With Atomoxetine, interactions typically fall into a few categories:

• Metabolism changes — Atomoxetine is broken down by an enzyme called CYP2D6 in the liver. Drugs that block this enzyme cause Atomoxetine to build up to higher-than-normal levels in your blood.
• Additive effects — Some drugs amplify Atomoxetine's effects on blood pressure, heart rate, or other body systems.
• Dangerous combinations — Certain medications are outright contraindicated with Atomoxetine due to the risk of severe reactions.

Medications That Interact with Atomoxetine

Major Interactions (Avoid or Use Extreme Caution)

MAO Inhibitors — Contraindicated

This is the most dangerous interaction. Do not take Atomoxetine if you've used an MAO inhibitor within the past 14 days. Combining them can cause a hypertensive crisis — a sudden, dangerous spike in blood pressure that can be life-threatening.

MAO inhibitors include:

• Phenelzine (Nardil)
• Tranylcypromine (Parnate)
• Isocarboxazid (Marplan)
• Selegiline (Emsam, Zelapar) — particularly the oral form
• Linezolid (Zyvox) — an antibiotic that also has MAO-inhibiting properties
• Methylene blue (IV) — used in certain medical procedures

Strong CYP2D6 Inhibitors

These medications significantly slow down how your body processes Atomoxetine, leading to much higher blood levels and increased risk of side effects. Your doctor may need to reduce your Atomoxetine dose if you take any of these:

• Fluoxetine (Prozac) — A common antidepressant and one of the strongest CYP2D6 inhibitors
• Paroxetine (Paxil) — Another SSRI antidepressant that strongly inhibits CYP2D6
• Quinidine — A heart rhythm medication
• Bupropion (Wellbutrin) — An antidepressant sometimes used off-label for ADHD

If you're taking one of these with Atomoxetine, you'll effectively have the same drug levels as a CYP2D6 poor metabolizer, meaning stronger effects and potentially more side effects.

QTc-Prolonging Drugs

Atomoxetine may prolong the QT interval (a measure of heart rhythm). Taking it with other QTc-prolonging medications increases the risk of dangerous heart rhythm abnormalities. These include:

• Cisapride — Contraindicated with Atomoxetine
• Certain antiarrhythmics (Amiodarone, Sotalol)
• Some antipsychotics (Haloperidol, Ziprasidone)
• Certain antibiotics (Azithromycin, Fluoroquinolones)

Albuterol and Beta-2 Agonists

Atomoxetine can increase the cardiovascular effects of Albuterol (Ventolin, ProAir) and other beta-2 agonists used for asthma. This may cause increased heart rate and blood pressure. If you use an inhaler for asthma, your doctor should know.

Moderate Interactions

• Cimetidine (Tagamet) — This heartburn medication can increase Atomoxetine levels
• Antihypertensives — Atomoxetine can raise blood pressure, potentially counteracting blood pressure medications. Your doctor may need to adjust doses.
• Pressor agents (Dopamine, Dobutamine) — Used in hospital settings; combined effects on blood pressure and heart rate

Supplements and OTC Medications to Watch

Over-the-counter products can interact with Atomoxetine too:

• Pseudoephedrine and phenylephrine (found in Sudafed and many cold medications) — These raise blood pressure and heart rate, which can add to Atomoxetine's cardiovascular effects. Check labels on cold and sinus medications.
• St. John's Wort — This herbal supplement affects multiple liver enzymes and can alter Atomoxetine levels unpredictably.
• Caffeine supplements — High-dose caffeine pills can amplify the heart rate and blood pressure effects of Atomoxetine.
• NSAIDs (Ibuprofen, Naproxen) — Generally safe, but long-term use alongside Atomoxetine may increase blood pressure. Monitor if you take these regularly.

Food and Drink Interactions

The good news: Atomoxetine has no significant food interactions. You can take it with or without food, though a high-fat meal may delay absorption slightly.

A few things to keep in mind:

• Caffeine — Coffee, tea, and energy drinks are fine in moderate amounts, but excessive caffeine may amplify jitteriness and increased heart rate.
• Alcohol — There's no direct interaction listed, but alcohol can worsen side effects like dizziness, drowsiness, and liver strain. Use caution, especially when starting treatment.
• Grapefruit — Unlike many medications, Atomoxetine is metabolized by CYP2D6 (not CYP3A4), so grapefruit juice is not a concern.

What to Tell Your Doctor

Before starting Atomoxetine, give your doctor a complete list of:

1. All prescription medications you're currently taking — especially antidepressants, blood pressure medications, and heart medications
2. Over-the-counter medications — including cold medicines, allergy pills, and pain relievers
3. Supplements and herbal products — including St. John's Wort, vitamins, and caffeine supplements
4. Recent medication changes — especially if you've stopped an MAOI in the last 14 days
5. Your complete medical history — heart conditions, liver problems, glaucoma, and mental health conditions are particularly important

If any new medications are prescribed by another doctor while you're on Atomoxetine, mention that you take it. Pharmacists also check for interactions when filling prescriptions, so using the same pharmacy for all your medications adds an extra safety layer.

Final Thoughts

Atomoxetine has fewer drug interactions than many medications, but the ones it does have can be serious — particularly the contraindication with MAO inhibitors and the significant interaction with CYP2D6 inhibitors like Fluoxetine and Paroxetine.

The best thing you can do is keep an updated medication list and share it with every provider and pharmacist you see. When in doubt, ask your pharmacist — they're the drug interaction experts.

For more about Atomoxetine, read our overview: What Is Atomoxetine? Uses, Dosage, and What You Need to Know. If you need help finding the medication at a pharmacy near you, Medfinder can help.