Understanding Lisdexamfetamine Side Effects

Lisdexamfetamine — sold as Vyvanse and now available as a generic — is one of the most commonly prescribed medications for ADHD and Binge Eating Disorder. Like all medications, it comes with potential side effects. Most are mild and manageable, but some require immediate medical attention.

This guide covers what to expect when you start taking Lisdexamfetamine, which side effects are normal, and when you should contact your doctor.

What Is Lisdexamfetamine?

Lisdexamfetamine is a Schedule II CNS stimulant and prodrug that converts to Dextroamphetamine in your body. It's FDA-approved for ADHD in patients aged 6 and older and moderate to severe Binge Eating Disorder in adults. For a deeper look at how it works, see our mechanism of action guide.

Common Side Effects

The following side effects are reported frequently in clinical trials and are generally mild to moderate. They often improve after the first few weeks as your body adjusts:

• Decreased appetite — This is the most common side effect. Many people notice they simply don't feel hungry, especially during the day when the medication is active.
• Insomnia or trouble falling asleep — Taking Lisdexamfetamine too late in the day can make it hard to sleep. It's best taken in the morning.
• Dry mouth — Staying hydrated and chewing sugar-free gum can help.
• Headache — Usually mild and may resolve on its own within the first week or two.
• Nausea — Taking the medication with food may reduce stomach discomfort.
• Irritability or mood changes — Some people feel edgy or anxious, especially as the medication wears off in the late afternoon.
• Dizziness — Usually mild. Avoid sudden position changes if this happens.
• Weight loss — Related to decreased appetite. Your doctor may monitor your weight, especially in children.
• Upper abdominal pain — More common in children.
• Increased heart rate — A slight increase in resting heart rate is common. Your doctor should monitor this at follow-up visits.
• Vomiting — More frequently reported in children than adults.
• Anxiety — If anxiety is significant, talk to your doctor about adjusting the dose.

Serious Side Effects

The following side effects are less common but require prompt medical attention. Call your doctor or go to the emergency room if you experience any of these:

• Cardiovascular events — Lisdexamfetamine can increase blood pressure and heart rate. In rare cases, stimulants have been associated with sudden death, stroke, and heart attack, primarily in patients with pre-existing heart conditions. Seek immediate help for chest pain, shortness of breath, or fainting.
• Psychiatric symptoms — New or worsening psychosis (seeing or hearing things that aren't there), mania, aggression, or severe mood swings. These are more likely at higher doses.
• Peripheral vasculopathy — Includes Raynaud's phenomenon — fingers or toes that turn white, blue, or feel numb and cold. Report this to your doctor.
• Serotonin syndrome — If you're also taking serotonergic medications like SSRIs, SNRIs, or Triptans, watch for agitation, rapid heartbeat, high body temperature, muscle twitching, or confusion. This is a drug interaction emergency.
• Seizures — Stimulants may lower the seizure threshold. If you have a seizure, seek emergency care immediately.
• Growth suppression — Long-term use in children may slow growth. Pediatricians should track height and weight regularly.
• Visual disturbances — Report any changes in vision to your doctor.

Lisdexamfetamine also carries a boxed warning about its potential for abuse and dependence. Take it exactly as prescribed and never share it with others.

Specific Populations

Children and Adolescents

Side effects like decreased appetite, weight loss, abdominal pain, and vomiting tend to be more common in children. Growth should be monitored at regular intervals. If growth is significantly affected, your doctor may consider a "drug holiday" during school breaks.

Pregnancy and Breastfeeding

Lisdexamfetamine is not recommended during pregnancy. It is excreted in breast milk, so the risks and benefits should be weighed carefully with your doctor.

Patients With Heart Conditions

People with pre-existing cardiovascular disease, structural heart defects, or serious heart rhythm abnormalities should generally not take Lisdexamfetamine. A cardiovascular evaluation is recommended before starting treatment.

Patients With Kidney Problems

For severe renal impairment (GFR 15–30), the maximum recommended dose is reduced to 50 mg/day. Lisdexamfetamine is not removed by dialysis.

How to Manage Common Side Effects

Most side effects can be managed with simple strategies:

• For decreased appetite: Eat a good breakfast before the medication kicks in. Have calorie-dense snacks available. Eat a larger dinner after the medication wears off.
• For insomnia: Take Lisdexamfetamine first thing in the morning — never in the afternoon. Practice good sleep hygiene (consistent bedtime, no screens before bed).
• For dry mouth: Drink water throughout the day. Sugar-free gum or lozenges can stimulate saliva production.
• For headaches: Stay hydrated and make sure you're eating enough. Over-the-counter pain relievers like Acetaminophen can help.
• For irritability as it wears off ("crash"): Talk to your doctor. They may adjust the dose, timing, or add a small booster dose.
• For increased heart rate or blood pressure: Your doctor should check vitals at every visit. Report palpitations, chest pain, or dizziness.

If any side effect becomes intolerable or doesn't improve after a few weeks, contact your doctor. They may adjust your dose — the typical range is 30 mg to 70 mg daily — or consider an alternative medication.

Final Thoughts

Lisdexamfetamine is an effective medication for ADHD and Binge Eating Disorder, but understanding its side effects helps you use it safely. Most common side effects are mild and improve with time. Serious side effects are rare but important to recognize.

If you're new to Lisdexamfetamine and want to learn more, check out our complete guide to Lisdexamfetamine. If you're having trouble finding it in stock, Medfinder can help you locate pharmacies near you that have it available.