Vyvanse, a long-acting central nervous system stimulant, is a valuable tool for managing attention-deficit hyperactivity disorder (ADHD) and binge eating disorder. Its active ingredient, dextroamphetamine, works by affecting key neurotransmitters, including dopamine and norepinephrine. However, due to its potent mechanism of action, Vyvanse carries a significant risk of adverse drug interactions. Combining it with certain other medications, supplements, and even foods can lead to dangerous side effects, ranging from serotonin syndrome to life-threatening cardiovascular events.
Absolutely Prohibited: Monoamine Oxidase Inhibitors (MAOIs)
The most severe interaction to avoid is the combination of Vyvanse with Monoamine Oxidase Inhibitors (MAOIs). This class of older antidepressants, which includes medications like isocarboxazid (Marplan) and phenelzine (Nardil), should never be taken concurrently with Vyvanse. The interaction can lead to a dangerous medical emergency called a hypertensive crisis, which involves a sudden, severe increase in blood pressure that can cause a stroke or heart attack. Patients must wait at least 14 days after stopping an MAOI before starting Vyvanse due to the long-lasting effects of MAOIs.
- Examples of MAOIs to avoid:
- Phenelzine (Nardil)
- Tranylcypromine (Parnate)
- Isocarboxazid (Marplan)
- Selegiline (Emsam)
- Linezolid (Zyvox) and methylene blue, which also have MAOI properties.
Medications and Supplements That Increase Serotonin Levels
Combining Vyvanse with other drugs or supplements that increase serotonin levels can lead to serotonin syndrome, a potentially life-threatening condition. Symptoms can include agitation, rapid heartbeat, and muscle rigidity. This risk exists with:
- SSRIs (e.g., fluoxetine, sertraline)
- SNRIs (e.g., venlafaxine, duloxetine)
- TCAs (e.g., amitriptyline)
- Triptans (e.g., sumatriptan)
- Certain opioid pain medications (e.g., tramadol)
- St. John's wort
Other Stimulants and Blood Pressure-Affecting Drugs
Combining Vyvanse with other stimulants or drugs that raise blood pressure can dangerously heighten cardiovascular side effects. This includes other ADHD medications (like Adderall), decongestants (like pseudoephedrine), and weight-loss medications (like phentermine). Vyvanse can also counteract the effects of some blood pressure medications. Bupropion, while sometimes used cautiously, can also raise blood pressure and increase seizure risk.
Substances Affecting Urinary and Gastric pH
Substances that alter the body's pH can affect how Vyvanse is metabolized and eliminated, potentially reducing its effectiveness or increasing side effects. Urinary alkalinizers (like acetazolamide or sodium bicarbonate) can slow Vyvanse elimination, increasing its concentration and risk of side effects. Conversely, urinary acidifiers (like large doses of vitamin C) can increase Vyvanse excretion, possibly reducing its effectiveness. Some antacids may also increase Vyvanse absorption.
Comparison Table of Potential Vyvanse Interactions
| Medication Class / Substance | Primary Risk | Example(s) | Safety Recommendation |
|---|---|---|---|
| MAO Inhibitors | Hypertensive crisis, serotonin syndrome | Phenelzine (Nardil), Isocarboxazid (Marplan) | ABSOLUTELY AVOID. Wait at least 14 days after stopping MAOI before starting Vyvanse. |
| Serotonergic Drugs | Serotonin syndrome | SSRIs (Zoloft), SNRIs (Cymbalta), Triptans (Imitrex) | Use with extreme caution under medical supervision. Monitor for symptoms. |
| Other CNS Stimulants | Increased cardiovascular side effects (BP, HR), anxiety | Adderall, Ritalin, Phentermine | Generally avoid combining unless directed and monitored by a doctor. |
| Decongestants | Increased cardiovascular effects | Pseudoephedrine (Sudafed) | Avoid use with Vyvanse due to added stimulant effects. |
| Urinary Alkalinizers | Increased Vyvanse levels, more side effects | Acetazolamide, Sodium Bicarbonate | Avoid or use with caution. Monitor for increased side effects. |
| Large Dose Vitamin C | Decreased Vyvanse effectiveness | High-dose supplements | Take at a different time than Vyvanse, as directed by a doctor. |
| St. John's Wort | Serotonin syndrome | Herbal supplement for depression | AVOID combining with Vyvanse. |
| Alcohol | Masked effects, worsened side effects | All alcoholic beverages | Avoid or use with caution. Can worsen side effects like dizziness and anxiety. |
The Importance of Consultation
Because Vyvanse has a broad range of potential interactions, it is essential to disclose all medications (prescription and over-the-counter), herbal supplements, and vitamins you are taking or plan to take to your doctor or pharmacist. Your healthcare provider can then assess your individual risk factors and monitor for adverse effects.
Conclusion
While Vyvanse can be an effective treatment, its powerful stimulant properties necessitate careful attention to potential drug interactions. The most critical warning is against the co-administration of MAOIs, which can cause a potentially fatal hypertensive crisis. Significant risks also exist with other serotonergic medications, stimulants, and substances that alter the body's pH. By maintaining open communication with your healthcare team, you can navigate these risks safely and ensure the intended therapeutic benefits of your Vyvanse treatment.
