Finding the right medicine for your brain can feel like a guessing game. When you first start taking a new medication, your doctor usually gives you a very small amount. Then they gradually increase the amount until your symptoms improve. This process takes time and patience, and frequent doctor visits to adjust your prescription can sometimes impact your monthly medication costs.
Vyvanse is a widely used and effective medication. It helps people focus, finish their work and control their actions as part of their overall mental wellness. However, because it is a strong stimulant, taking too much of it can make you feel terrible. If the dose is pushed too high, the medicine stops helping and starts hurting, which can quickly ruin your sleep and disrupt your daily nutrition habits.
Who is a good candidate for Vyvanse?
Vyvanse is a prescription medicine approved for two main problems. The first is attention deficit hyperactivity disorder, which is commonly known as ADHD. People with ADHD have a hard time paying attention, staying still or controlling their impulses. Vyvanse helps calm their brain so they can focus on one task at a time.
The second condition is binge eating disorder. According to the Cleveland Clinic, this is an illness characterized by a strong urge to eat large amounts of food in a short time, with a sense of being unable to stop. As noted by the Mayo Clinic, Vyvanse is the first medication approved by the government to help treat severe binge eating in adults.
A good candidate for this drug is someone who has been officially diagnosed with one of these two conditions by a medical practitioner. They should also have a healthy heart, as this medication can place additional stress on the cardiovascular system.
Why early detection matters
Dr. Justus Rabach, MD, explains, “Recognizing a high dose early is critical. If you take too much stimulant medication for a long time, it can put dangerous strain on your heart and raise your blood pressure. Finding the perfect, lowest effective dose protects your physical health and prevents severe anxiety or panic attacks.”
There are numerous signs to look out for if you think your Vyvanse dose might be too high:
1. A racing heart
One of the most common signs of a high dose is a pounding heart. You might be sitting perfectly still on the couch, but your heart feels like you just ran a race. This happens because Vyvanse is a central nervous system stimulant. It speeds up the flow of messages between your brain and your body.
While a small increase in heart rate is normal when you first start the medicine, a very fast or irregular heartbeat is a warning sign. The Cleveland Clinic explains that if you constantly feel your heart fluttering or if your resting pulse remains very high throughout the day, your dose is likely too strong for your body to handle safely.
2. Inability to sleep at night
Vyvanse is a long-acting medication. It is designed to be slowly released into your body over 10 to 14 hours. If your dose is correct and you take it early in the morning, it should wear off by bedtime, allowing you to fall asleep normally.
However, if your dose is too high, the medicine stays active in your system late into the night. You might lie in bed feeling wide awake, with your mind racing with thoughts. If you are only getting a few hours of sleep every night, this lack of rest will eventually make your ADHD symptoms much worse.
3. Feeling jittery or extremely anxious
A correct dose of ADHD medication should make you feel calm, clear and ready to tackle the day by quieting the constant noise in your head. On the other hand, too much of the medicine will make you feel the exact opposite. You might feel very nervous, restless or on edge.
Some people describe this as feeling like they drank ten cups of coffee. You might shake, bite your nails or feel a sense of dread for no reason. Johns Hopkins Medicine notes that when stimulants over-activate the brain, they can easily trigger severe anxiety or even panic attacks in people who normally do not have anxiety.
4. Complete lack of appetite
It is very normal to lose a little bit of your appetite when you take a stimulant. Many people skip breakfast or eat a smaller lunch. However, if your dose is too high, the thought of food might actually make you feel sick. You might go the entire day without eating anything and still not feel hungry.
This is very dangerous because your brain needs food for energy. If you do not eat, you will feel weak, dizzy and cranky when the medicine finally wears off in the evening. If you are losing significant weight very quickly without trying, you need to tell your doctor.
If you struggle to eat during the day because of your medication, try a large, protein-rich breakfast before taking your pill. Eating eggs, meats or protein shakes in the morning gives your brain the fuel it needs to work well with the medication, and it can reduce the “crash” feeling later in the day.
5. Feeling like a zombie
This is a very common complaint from parents of children who take ADHD medication, but it happens to adults as well. When the dose is too high, you might lose your personality, leaving you feeling emotionally flat, quiet and robotic. Instead of just focusing on your work, you might hyper-focus so much that you ignore your friends, your family or your hobbies. You stop laughing at jokes and feel disconnected from the world. The medicine should help you be the best version of yourself, not erase who you are. If you feel like a robot, the dose is too high.
What happens when your Vyvanse dose is too low?
Sometimes, the problem is not having too much medicine, but having too little. If your dose is too low, it may feel as if you did not take anything. You will still struggle to focus on your work. You will easily get distracted by noises or your own thoughts. You might still feel the urge to get up and walk around during meetings or classes.
Another sign of a low dose is feeling very tired. Sometimes, a tiny amount of a stimulant can actually make people with ADHD feel sleepy instead of awake. If your medicine wears off by noon and you feel exhausted, you might need a slight increase.
What happens if you take Vyvanse without ADHD?
Many college students and adults mistakenly think that taking someone else’s ADHD medicine will make them smarter or help them study better. If you do not have ADHD, your brain already has enough dopamine and norepinephrine. These are the chemicals that help you focus.
The National Institutes of Health (NIH) explains that when a person without ADHD takes a stimulant, it floods their brain with too many chemicals. This can cause intense euphoria, or a “high.” However, it also causes severe jitteriness, heart problems and a terrible physical crash when it wears off. Taking this medicine without a prescription is very dangerous and can quickly lead to addiction.
When to see a doctor
Most side effects can be managed by calling your doctor and asking them to reduce your dose. However, some signs mean you need medical help right away. You should go to the emergency room if you feel a crushing pain in your chest or if your left arm goes numb. This may indicate a heart attack.
You should also seek immediate help if you start seeing or hearing things that are not there, which is called hallucinations. If you feel extremely paranoid, like someone is out to get you, this is a rare but severe reaction to a high dose. Do not wait for your next appointment if these scary things happen.
Bottom line
Finding the correct Vyvanse dose requires careful monitoring and clear communication with your doctor. If you experience a racing heart, severe anxiety, total loss of appetite or feel emotionally flat like a robot, your dose is likely too high. Recognizing these warning signs early allows you to lower the medication to a safe level, protecting your heart and your mental health while still treating your ADHD.
Frequently Asked Questions
What is the average dose of Vyvanse for adults?
The starting dose is typically 30 milligrams per day, and the average effective dose for most adults is 40-50 milligrams per day.
Can you drink coffee while on Vyvanse?
It is best to avoid coffee and energy drinks because combining caffeine with a prescription stimulant can cause severe anxiety and a dangerously fast heart rate.
Why do doctors prefer Vyvanse over Adderall?
Doctors often prefer Vyvanse because it is a “prodrug,” meaning it must be processed by the digestive system before it works, making it much harder to abuse or misuse compared to Adderall.
Citations
Guerdjikova AI, Mori N, Casuto LS, McElroy SL. Novel pharmacologic treatment in acute binge eating disorder – role of lisdexamfetamine. Neuropsychiatric Disease and Treatment. 2016;12:833. doi:https://doi.org/10.2147/ndt.s80881
Cleveland Clinic. Binge Eating Disorder. Cleveland Clinic. Published April 17, 2023. https://my.clevelandclinic.org/health/diseases/17652-binge-eating-disorder
Mayo Clinic. Lisdexamfetamine Dimesylate (Oral Route) Description and Brand Names – Mayo Clinic. www.mayoclinic.org. Published 2026. https://www.mayoclinic.org/drugs-supplements/lisdexamfetamine-dimesylate-oral-route/description/drg-20070888
Cleveland Clinic. Lisdexamfetamine Capsule. Cleveland Clinic. Published 2026. https://my.clevelandclinic.org/health/drugs/18318-lisdexamfetamine-capsule
John Hopkins Medicine. Attention-Deficit / hyperactivity disorder (ADHD) in children. John Hopkins Medicine. Published 2024. https://www.hopkinsmedicine.org/health/conditions-and-diseases/adhdadd
National Institute on Drug Abuse. Prescription Stimulants DrugFacts. National Institute on Drug Abuse. Published June 6, 2018. https://nida.nih.gov/publications/drugfacts/prescription-stimulants
Johns Hopkins Medicine. Impulsivity and Binge-Eating in Children: Connecting the Dots. Hopkinsmedicine.org. Published 2016. Accessed February 11, 2026. https://www.hopkinsmedicine.org/news/articles/2015/12/impulsivity-and-binge-eating-in-children-connecting-the-dots