What Is A Lethal Dose Of Vyvanse (Lisdexamfetamine)?

The generic name for Vyvanse is lisdexamfetamine dimesylate (LDX), a d-amphetamine prodrug. This means that after Vyvanse is administered, it’s metabolized into a pharmacologically active drug.

In a study on rats published by the National Library of Medicine, the lethal dose of LDX in rats was found to be more than five times higher than the lethal dose of d-amphetamine.

The lethal dose of Vyvanse for humans is over 1,000 milligrams (mg) per kilogram (kg) of body weight.

Learn more about the fatal dose of commonly abused drugs.

Determining The Lethal Dose Of Vyvanse

Vyvanse is a central nervous system stimulant used to treat attention-deficit/hyperactivity disorder (ADHD) and binge eating disorder (BED).

In the 28-day study involving rats, one rat died at 1,000 mg/kg, so it was determined that doses more than 1,000 mg/kg are lethal.

This suggests that the data for determining the lethal dose of a single oral dose of LDX is insufficient. The level at which there was no observed effect was less than 30 mg/kg per day.

How Vyvanse Is Normally Prescribed

Vyvanse (lisdexamfetamine) is prescribed differently depending on the condition being treated, with doctors carefully adjusting doses based on patient response and tolerance. In the treatment of ADHD, the starting dosage of Vyvanse is recommended at 30 mg per day, taken in the morning, and can increase in intervals of 10 mg or 20 mg at weekly intervals to reach a maximum daily dose of 70 mg.

For treating binge eating disorder (BED), the recommended starting dosage follows a similar pattern at 30 mg per day. The dose is increased slowly over several weeks to eventually reach the recommended target dosage range of 50 to 70 mg per day. Healthcare providers will typically schedule regular follow-up appointments during the initial months of treatment to monitor for adverse effects and make dosage adjustments.

Factors That May Contribute To Vyvanse Overdose

While overdosing on Vyvanse by itself is not very common, the danger increases when people mix it with alcohol or other drugs. Vyvanse is a stimulant that speeds up your central nervous system, while alcohol is a depressant that slows it down, so when someone takes both at the same time, these substances work against each other, leading to serious stress on the central nervous system.

This may lead to:

• Stroke: blood vessels in the brain can become damaged or blocked, cutting off oxygen to brain tissue
• Heart Attack: the heart muscle can be damaged when it doesn’t get enough blood and oxygen
• Hallucinations: seeing or hearing things that aren’t really there due to brain chemistry being severely disrupted
• Confusion: severe mental disorientation where people can’t think clearly or understand what’s happening around them
• Seizures: uncontrolled electrical activity in the brain that causes violent shaking and loss of consciousness
• Alcohol Poisoning: dangerous levels of alcohol in the blood that can shut down vital body functions
• Alternating High and Low Blood Pressure: blood pressure swinging wildly between dangerous extremes that can damage organs
• Death: complete failure of vital body systems when the stress becomes too much for the body to handle

The combination of Vyvanse with alcohol or other drugs creates unpredictable and potentially deadly effects because the body can’t properly process these conflicting substances. This is why it’s important for people taking Vyvanse to avoid drinking alcohol or using other drugs.

Recognizing The Signs Of A Vyvanse Overdose

The most important warning signs to be on the lookout for are convulsions and coma, as these symptoms usually precede fatal overdoses.

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Warning signs of Vyvanse overdose include:

• restlessness
• tremors
• fever
• spasms
• nausea
• vomiting
• dilated pupils

More serious signs of Vyvanse overdose include chest pain that may indicate heart problems, along with severe abdominal pain. The person may experience seizures, develop dangerously high body temperature, or fall into a coma. Mental symptoms can include psychosis where the person loses touch with reality and may see or hear things that aren’t there, and they may develop suicidal thoughts that put them at risk of self-harm.

What To Do If You Suspect A Vyvanse Overdose

If you suspect someone is overdosing on Vyvanse, call 911 immediately. While waiting for emergency services to arrive, try to keep the person calm and still, as physical activity can further elevate heart rate and body temperature. If the person is having a seizure, clear the area around them of anything that could cause injury and do not attempt to restrain them.

Give emergency responders as much information as possible, including how much Vyvanse was taken, when it was taken, and whether any other substances like alcohol or other drugs were involved. If the medication bottle is available, bring it to the hospital so medical staff can see the exact dosage. Never leave the person alone, and if they lose consciousness, place them on their side to prevent choking.

For more information about addiction recovery, contact the Substance Abuse and Mental Health Services Administration (SAMHSA).

Written by the Addiction Resource Editorial Staff