What You Need to Know About Dextroamphetamine Drug Interactions

Dextroamphetamine can interact with a wide range of medications, supplements, and even certain foods. Some interactions are minor, while others can be life-threatening. Knowing what to watch for — and what to tell your doctor — can help you stay safe while getting the most from your treatment.

This guide covers the major and moderate drug interactions, over-the-counter products to watch for, and food and drink considerations.

How Drug Interactions Work

Drug interactions happen when one substance changes how another works in your body. With Dextroamphetamine, interactions can:

• Increase its effects — making side effects worse or raising the risk of toxicity
• Decrease its effects — making it less effective at treating your ADHD or narcolepsy
• Create dangerous new effects — like serotonin syndrome or hypertensive crisis

Interactions can involve prescription drugs, over-the-counter medications, supplements, and food. Always give your doctor and pharmacist a complete list of everything you take.

Major Drug Interactions (Dangerous — Avoid These Combinations)

These interactions are serious and can be life-threatening. In most cases, these medications should not be taken with Dextroamphetamine:

MAO Inhibitors

Examples: Phenelzine (Nardil), Tranylcypromine (Parnate), Isocarboxazid (Marplan), Selegiline (Emsam), Rasagiline (Azilect)

This is the most dangerous interaction. Combining Dextroamphetamine with an MAO inhibitor — or taking Dextroamphetamine within 14 days of stopping one — can cause a hypertensive crisis (dangerously high blood pressure), which can lead to stroke or death. This combination is contraindicated.

Serotonergic Drugs

Examples: Fluoxetine (Prozac), Sertraline (Zoloft), Paroxetine (Paxil), Venlafaxine (Effexor), Duloxetine (Cymbalta), Sumatriptan (Imitrex), and other triptans

Combining Dextroamphetamine with drugs that increase serotonin raises the risk of serotonin syndrome — a potentially fatal condition characterized by agitation, rapid heartbeat, high body temperature, muscle rigidity, and confusion. While many people safely take an SSRI and Dextroamphetamine together under medical supervision, the combination requires careful monitoring.

Tricyclic Antidepressants

Examples: Amitriptyline (Elavil), Nortriptyline (Pamelor), Imipramine (Tofranil), Desipramine (Norpramin)

Dextroamphetamine can enhance the effects of tricyclic antidepressants, increasing the risk of cardiovascular side effects. Your doctor may need to adjust doses if this combination is necessary.

CYP2D6 Inhibitors

Examples: Quinidine, Ritonavir (Norvir), Paroxetine (Paxil), Fluoxetine (Prozac), Bupropion (Wellbutrin)

These drugs can slow down how your body processes Dextroamphetamine, leading to higher levels in your blood and increased risk of side effects.

Moderate Drug Interactions (Use Caution)

These interactions are significant but may be manageable with dose adjustments or monitoring:

• Antacids and urinary alkalinizers (e.g., sodium bicarbonate) — These can increase the absorption of Dextroamphetamine, making it stronger than intended.
• Urinary acidifiers and Ascorbic Acid (Vitamin C) — These speed up the elimination of Dextroamphetamine from your body, making it less effective.
• Antihypertensive medications (e.g., Lisinopril, Amlodipine, Metoprolol) — Dextroamphetamine can raise blood pressure, reducing the effectiveness of blood pressure medications.
• Phenobarbital and Phenytoin (Dilantin) — These anti-seizure medications may interact with Dextroamphetamine, and levels of either drug may be affected.
• Lithium — May reduce the stimulant effects of Dextroamphetamine.
• Haloperidol (Haldol) — Can reduce the effectiveness of Dextroamphetamine.
• Proton pump inhibitors (e.g., Omeprazole, Pantoprazole) — May alter the absorption of Dextroamphetamine by changing stomach pH.

Supplements and OTC Products to Watch

Several common supplements and over-the-counter products can interact with Dextroamphetamine:

• Vitamin C (Ascorbic Acid) — Can decrease Dextroamphetamine levels. Avoid taking large doses of Vitamin C or drinking citrus juice close to your medication time.
• Decongestants containing Pseudoephedrine or Phenylephrine (e.g., Sudafed) — These are stimulants themselves and can add to the cardiovascular effects of Dextroamphetamine, raising heart rate and blood pressure.
• St. John's Wort — Has serotonergic properties and may increase the risk of serotonin syndrome when combined with Dextroamphetamine.
• Melatonin — Generally considered safe to use with Dextroamphetamine and may help counteract stimulant-related insomnia, but talk to your doctor first.
• Caffeine supplements — Can intensify side effects like increased heart rate, anxiety, and insomnia.

Food and Drink Interactions

• Citrus juice and acidic foods — Orange juice, grapefruit juice, and other acidic foods can reduce the absorption and effectiveness of Dextroamphetamine. Avoid consuming these within an hour of your dose.
• Alkaline foods — Foods that make your urine more alkaline (like certain vegetables) may increase absorption and prolong the effects.
• Caffeine — Coffee, energy drinks, and caffeinated teas can amplify Dextroamphetamine's stimulant effects. Many patients find they need to reduce caffeine intake after starting Dextroamphetamine to avoid jitteriness, rapid heartbeat, and trouble sleeping.
• Alcohol — While not a direct pharmacological interaction, alcohol can impair judgment about how the medication is affecting you and can worsen side effects like dizziness and cardiovascular strain.

What to Tell Your Doctor

Before starting Dextroamphetamine, make sure your doctor knows about:

• All prescription medications you currently take — including any that were recently stopped (especially MAO inhibitors)
• Over-the-counter medications — including cold medicines, antacids, and pain relievers
• Supplements and vitamins — including Vitamin C, St. John's Wort, and herbal products
• Your caffeine intake
• Any recreational substances
• Changes to any medication during treatment — always check before starting or stopping anything

Your pharmacist is also a valuable resource. They can run interaction checks every time you fill a prescription.

Final Thoughts

Dextroamphetamine is a safe and effective medication when used as prescribed — but drug interactions are a real concern. The most important thing you can do is be completely transparent with your healthcare team about everything you take. When in doubt, ask before mixing.

For more information about Dextroamphetamine, check out our guides on side effects, how it works, and how to find it in stock near you.