Is 0.073 ± 0.019 mg/L a High Adderall Level?
A plasma amphetamine concentration of 0.073 mg/L (73 ng/mL) falls within the expected therapeutic range for standard oral Adderall dosing and is not considered high or toxic.
Therapeutic Context and Expected Concentrations
Following administration of three 5 mg immediate-release tablets (15 mg total dose), average maximal dextroamphetamine plasma concentrations of 36.6 ng/mL are achieved at approximately 3 hours 1.
After a single 15 mg sustained-release capsule, maximal dextroamphetamine plasma concentrations average 23.5 ng/mL, obtained approximately 8 hours after dosing 1.
In a controlled trial of adults with ADHD, the average effective oral dose was 54 mg daily (administered in two divided doses), which produced therapeutic benefit without significant toxicity 2.
Your reported level of 73 ng/mL is consistent with therapeutic dosing in the range of 15–30 mg per dose, particularly if measured near peak concentration 1, 2.
Safety Thresholds and Toxic Levels
Therapeutic stimulant doses (0.3 mg/kg orally in children, scaled proportionally in adults) rarely cause serious toxicity; severe toxicity occurs only at doses approximately 50 times higher than therapeutic levels 3.
Paranoid hallucinations and psychotic symptoms have been documented at single doses of 300 mg amphetamine in normal adults—far exceeding the dose implied by your plasma level 3.
Cardiovascular damage and CNS toxicity are documented risks only with extremely high doses (50 times therapeutic levels), not at concentrations in the 70 ng/mL range 3.
The American Academy of Child and Adolescent Psychiatry explicitly states that plasma levels of methylphenidate (and by extension, amphetamines) do not correlate reliably with clinical response or toxicity, and routine therapeutic drug monitoring is not recommended for guiding treatment 3.
Clinical Interpretation Algorithm
Step 1: Assess Clinical Context
- If the patient is asymptomatic or experiencing only mild expected stimulant effects (increased alertness, mild tachycardia, appetite suppression), the level of 73 ng/mL is consistent with therapeutic dosing and requires no intervention 3, 1.
Step 2: Evaluate for Signs of Toxicity
- Look for hyperactivity, hyperthermia, tachycardia, tachypnea, mydriasis, tremors, or seizures—these are the hallmark signs of amphetamine overdose, not the plasma level itself 4.
- If these signs are absent, the plasma concentration alone does not indicate toxicity 3, 4.
Step 3: Consider Timing of Sample
- Amphetamine plasma levels peak 3 hours after immediate-release formulations and 8 hours after sustained-release formulations 1.
- A level of 73 ng/mL drawn at peak time after a 15–20 mg dose is entirely expected; the same level drawn as a trough (pre-dose) would suggest accumulation or higher dosing 1.
Step 4: Rule Out Misuse or Overdose
- Diagnosis of amphetamine intoxication is confirmed by clinical presentation (tremors, seizures, hyperthermia) and history of ingestion, not by plasma levels alone 4.
- Differential diagnoses include other CNS stimulants, serotonin syndrome, or anticholinergic toxicity 4.
Key Pitfalls to Avoid
Do not interpret plasma amphetamine levels in isolation; they do not predict clinical response or toxicity in the therapeutic range 3.
Do not assume toxicity based solely on a number; a level of 73 ng/mL is well below the threshold associated with serious adverse effects (which occur at doses 50× therapeutic) 3.
Do not confuse animal toxicity data with human clinical practice; rodent studies used subcutaneous doses 50–80 times higher than oral therapeutic doses and are irrelevant to your patient 3.
Recognize that the standard deviation (±0.019 mg/L or ±19 ng/mL) in your measurement reflects normal pharmacokinetic variability and does not indicate a problem 1, 5.
Bottom Line for Clinical Decision-Making
A plasma amphetamine concentration of 73 ng/mL is consistent with therapeutic oral dosing of Adderall (15–30 mg per dose) and does not warrant dose reduction or discontinuation in the absence of clinical toxicity 3, 1, 2.
Manage the patient based on clinical signs, not the plasma level; if the patient is symptomatic, treat the symptoms (benzodiazepines for seizures, β-blockers for tachyarrhythmias, IV fluids for hyperthermia) 4.
Plasma amphetamine monitoring is not recommended for routine therapeutic management; use it only to confirm suspected overdose or assess compliance 3.