Vyvanse (lisdexamfetamine) is a medication prescribed for conditions like ADHD and binge eating disorder. Its safety and effectiveness depend significantly on avoiding certain interactions that can lead to adverse health outcomes. While some substances may alter how well Vyvanse works, the most critical concern lies in combinations that pose severe health risks.
Dangerous and Contraindicated Drug Interactions
Some interactions with Vyvanse are not merely about reduced effectiveness; they can be severely harmful and must be avoided entirely.
Monoamine Oxidase Inhibitors (MAOIs)
Combining Vyvanse with Monoamine Oxidase Inhibitors (MAOIs), a class of antidepressants, is extremely dangerous. This combination can cause a hypertensive crisis, a severe and sudden increase in blood pressure that can be life-threatening. Because MAOIs have a long-lasting effect in the body, Vyvanse should not be taken within 14 days of using an MAOI.
Serotonergic Drugs: Risk of Serotonin Syndrome
Vyvanse can increase levels of neurotransmitters like serotonin. Combining it with other medications that also increase serotonin, such as many common antidepressants (SSRIs, SNRIs, TCAs), certain pain medications (triptans, some opioids), and even some herbal supplements like St. John's Wort, increases the risk of serotonin syndrome. Serotonin syndrome can range from mild to severe and may require immediate medical attention. Symptoms can include agitation, rapid heartbeat, high body temperature, and muscle rigidity.
Other Central Nervous System (CNS) Stimulants
Combining Vyvanse with other CNS stimulants, including other medications for ADHD, weight loss pills, or even certain over-the-counter decongestants (like pseudoephedrine), can amplify the stimulant effects on the body. This can lead to increased cardiovascular side effects such as elevated heart rate and blood pressure, anxiety, and sleep disturbances. Such combinations should generally be avoided or used only under strict medical supervision.
Substances That May Alter Vyvanse's Effectiveness
While not posing the same level of immediate danger as the contraindicated interactions, certain substances can influence how the body processes Vyvanse, potentially reducing its intended therapeutic effect. These interactions primarily affect the excretion of the active medication from the body.
Acidic Substances and Urinary Excretion
Vyvanse is a prodrug that is converted to the active compound, dextroamphetamine, in the body. The rate at which the body eliminates dextroamphetamine can be affected by the acidity of the urine. Highly acidic urine, which can result from consuming large amounts of substances that acidify the body, may lead to faster excretion of the active drug, potentially reducing its duration of action or overall effectiveness. High doses of Vitamin C supplements, for example, can acidify urine. While the impact of dietary sources of acidity is generally less significant, it is worth discussing with a healthcare provider if you have concerns.
Conclusion
Focusing on "what cancels out Vyvanse" is less accurate than understanding which interactions can make the medication unsafe or less effective. The most critical interactions involve combinations that lead to dangerous health conditions like hypertensive crisis or serotonin syndrome. Always inform your prescribing physician and pharmacist about all medications, supplements, and herbal products you are taking. They are the best resources for identifying potential interactions and advising on how to manage them safely. Never attempt to alter your Vyvanse dosage or combine it with other substances without consulting a healthcare professional.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare professional regarding your specific medical needs and potential drug interactions.
