From the Guidelines
The patient's amphetamine level of >15000 ng/mL is significantly elevated, indicating excessive Adderall XR exposure, and I strongly recommend immediately discontinuing the Adderall XR 40 mg daily and seeking urgent medical evaluation. This high level suggests potential overdose or medication misuse, which can lead to serious cardiovascular complications, neurotoxicity, and psychiatric symptoms, as noted in the clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents 1. The patient should be monitored for symptoms like tachycardia, hypertension, hyperthermia, agitation, and psychosis.
According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults, amphetamines can cause elevated blood pressure, and the possible management strategy is to discontinue or decrease the dose 1. After medical stabilization, if ADHD treatment is still needed, consider alternative non-stimulant medications like atomoxetine, guanfacine, or clonidine. If stimulant therapy must be resumed later, it should be at a lower dose with strict monitoring and frequent drug level testing. Amphetamine levels in therapeutic Adderall use typically range from 100-200 ng/mL, so this reading exceeds normal levels by approximately 75-150 times, representing a potentially life-threatening situation requiring immediate intervention.
Some key points to consider in the management of this patient include:
- Monitoring for symptoms of overdose or medication misuse
- Discontinuing the current stimulant medication and considering alternative treatments
- Implementing strict monitoring and frequent drug level testing if stimulant therapy is resumed
- Being aware of the potential for serious cardiovascular complications, neurotoxicity, and psychiatric symptoms associated with high amphetamine levels, as noted in the clinical practice guideline 1.
From the FDA Drug Label
OVERDOSAGE Individual patient response to amphetamines varies widely. While toxic symptoms occasionally occur as an idiosyncrasy at doses as low as 2 mg, they are rare with doses of less than 15 mg; 30 mg can produce severe reactions, yet doses of 400 to 500 mg are not necessarily fatal. The patient is currently taking Adderall XR 40 mg daily, which contains amphetamine. The dose of >15,000 is extremely high and can be considered an overdose.
- Key symptoms of amphetamine overdose include:
- Restlessness
- Tremor
- Hyperreflexia
- Rhabdomyolysis
- Rapid respiration
- Hyperpyrexia
- Confusion
- Assaultiveness
- Hallucinations
- Panic states
- Treatment should be consulted with a Certified Poison Control Center and may include gastric lavage, administration of activated charcoal, administration of a cathartic, and sedation 2.
From the Research
Amphetamine Toxicity and Adderall XR
- Amphetamine abuse is associated with significant health risks, including cardiovascular and neurological complications, as well as secondary conditions such as rhabdomyolysis, disseminated intravascular coagulation (DIC), gastrointestinal (GI) bleeding, hepatic necrosis, and renal failure 3.
- The patient is currently taking Adderall XR 40 mg daily, which contains amphetamine and dextroamphetamine, and is used to treat attention-deficit/hyperactivity disorder (ADHD) and narcolepsy 4.
Clinical Pharmacokinetics of Amfetamine
- Amfetamine-type stimulants, including Adderall, have a good oral bioavailability, high distribution volume, and low binding to plasma proteins, with an elimination half-life of 6-12 hours 5.
- Both hepatic and renal clearance contribute to the elimination of amfetamine-type stimulants from the body, and they can be detected in alternative matrices such as saliva, hair, nails, and sweat 5.
Cardiovascular Effects of Amphetamines
- Amphetamines can cause increases in heart rate and blood pressure, although the clinical significance of these effects is still being studied 6.
- The patient's current dosage of Adderall XR 40 mg daily is within the standard recommended dosage of 5-60 mg daily for humans with ADHD or narcolepsy 4.
Amphetamine Neurotoxicity
- Amphetamine analogs, including methamphetamine, have been shown to have the potential to damage brain monoaminergic cells directly, although the characteristics of this neurotoxicity are still being researched 7.
- The patient's long-term use of Adderall XR may pose a risk of amphetamine neurotoxicity, although the exact risks and challenges associated with this are still being investigated 7.