Adapted from:
Stimulant Dosing Limits
August 7, 2023Chris Aiken, MD and Kelvin Quiñones-Laracuente, MD, PhD.
From The Carlat Psychiatry Report
Max Dosing Table
| Brand | Generic | Adult Start | Peds Start | Titration | Max Dose | Formulation / Duration | FDA Age |
|---|---|---|---|---|---|---|---|
| Adderall | Mixed amphetamine salts | 5–10 mg QAM or BID | 5 mg QAM | ^ 5–10 mg weekly | 40–60 mg | IR • 4–6 hr | >= 3 yrs |
| Adderall XR | Mixed amphetamine salts | 10–20 mg | 10 mg | ^ 5–10 mg weekly | 40 mg | ER • 10–12 hr | >=6 yrs |
| Adhansia XR | Methylphenidate | 25 mg | 25 mg | ^ 10–15 mg weekly | 100 mg | ER • 12–16 hr | >=6 yrs |
| Adzenys XR | Amphetamine | 12.5 mg | 6.3 mg | ^ 3.1–6.3 mg weekly | 18.8 mg | ER • 10–12 hr | >=6 yrs |
| Azstarys | Serdexmethylphenidate / dexmethylphenidate | 39.2 / 7.8 mg | 39.2 / 7.8 mg | — | 52.3 / 10.4 mg | ER • ~13 hr | >=6 yrs |
| Concerta / Relexxii | Methylphenidate | 18–36 mg | 18 mg | ^ 18 mg weekly | 72 mg | ER • 10–12 hr | >=6 yrs |
| Dyanavel XR | Amphetamine | 5–10 mg | 2.5–5 mg | ^ 2.5–5 mg weekly | 20 mg | ER • 12–13 hr | >=6 yrs |
| Evekeo | Amphetamine | 5–10 mg | 5 mg | ^ 5–10 mg weekly | 60 mg | IR • 4–6 hr | >=3 yrs |
| Jornay PM | Methylphenidate | 20 mg (evening dosing) | 20 mg | ^ 20 mg weekly | 100 mg | ER delayed onset • 12–14 hr | >=6 yrs |
| Mydayis | Mixed amphetamine salts | 12.5 mg | 12.5 mg | ^ 12.5 mg weekly | 50 mg | ER • 14–16 hr | >=13 yrs |
| Ritalin / Methylin | Methylphenidate | 10–20 mg | 5 mg BID | ^ 5–10 mg weekly | 60 mg | IR • 3–4 hr | >=6 yrs |
| Ritalin LA / Metadate CD | Methylphenidate | 10–20 mg | 10 mg | ^ 10 mg weekly | 60 mg | ER • 8–10 hr | >=6 yrs |
| Ritalin SR / Metadate ER | Methylphenidate | 10–20 mg | 10 mg | ^ 10 mg weekly | 60 mg | ER • 6–8 hr | >=6 yrs |
| Vyvanse | Lisdexamfetamine | 30 mg | 30 mg | ^ 10–20 mg weekly | 70 mg | ER (prodrug) • 12–14 hr | >=6 yrs |
Adapted from: Physician’s Desk Reference
Amphetamines
The FDA sets the maximum for Adderall (IR or XR) at a dose of 40 mg/day for adult ADHD. However, they allow up to 60 mg/day for more severe cases of ADHD, as well as for narcolepsy. That 40–60 mg max was derived from a large registration trial of adult ADHD. The study compared three doses of Adderall XR (20, 40, and 60 mg/day), and found no significant difference between them in terms of safety and efficacy (Weisler RH et al, CNS Spectr 2006;11(8):625–639). There was some evidence that people with more severe ADHD did better on the higher doses of 40–60 mg, but that finding was limited due to its secondary, “data-fishing” nature.
We recommend thinking of the dose in three zones: the safe zone (below 40 mg/day), the gray zone (40–60 mg/day), and the danger zone (above 60 mg/day). Going up to 60 mg/day may be justified when the symptoms are severe, but you’d want to document their presence on the mental status exam and verify that the ADHD is affecting the patient’s functioning. We are not aware of research justifying a dose above 60 mg/day, which would land in the danger zone.
Higher doses may also be justified when a longer duration is needed. Mydayis (a very extended-release version of Adderall) has a maximum dose of 50 mg, but this leads to similar plasma levels as Adderall XR 40 mg because the dose is spread out over 16 hours instead of 12. When extending the duration, make sure the patient is getting adequate sleep so they are not relying on the stimulant for symptoms of sleep deprivation.
Methylphenidates
For methylphenidate, the FDA gives a clear maximum, although it varies slightly by formulation. That max is 60 mg/day for methylphenidate IR (Ritalin), but higher doses are allowed for products with longer durations such as Concerta (72 mg over 12 hours) and Adhansia (100 mg over 16 hours).
A few methylphenidate products have lower dose caps because more of the drug is absorbed. These include the transdermal formulation (Daytrana is given at half the usual methylphenidate dose) and orally disintegrating tablets (Cotempla ODT is dosed at 86% of the usual dose and Adzenys ODT at 65%).
Dosing in the elderly
Adult ADHD is a relatively new concept, and geriatric ADHD is newer still. The middle-aged patients who started stimulants 20 years ago—when the FDA first approved them in adults—are now entering their retirement years with little data to guide them. There are no controlled trials in patients with ADHD after age 50, but a few observational studies suggest older adults continue to benefit, although at lower doses (eg, average doses of 30 mg/day for methylphenidate and 10 mg/day for amphetamine and dextroamphetamine) (Michielsen M et al, J Atten Disord 2021;25(12):1712–1719).
There are three reasons to consider lowering the dose as patients age. Older adults are more susceptible to the cardiovascular effects and—based on animal data—the neurotoxic effects of stimulants. In animal models, the same dose of amphetamine reached twice the levels in the brains of older rats compared to younger ones, suggesting that older adults may not need as high a dose to achieve a good response (Berman SM et al, Mol Psychiatry 2009;14(2):123–142).