What is the lowest effective dose of stimulant medications (e.g., methylphenidate, amphetamine, lisdexamfetamine) for an adult with attention‑deficit/hyperactivity disorder who has no contraindications such as uncontrolled hypertension, significant cardiac disease, history of stimulant misuse, or severe anxiety?

Lowest Effective Starting Dose for Stimulant Therapy in Adult ADHD

For adults with ADHD and no contraindications, begin methylphenidate at 5 mg three times daily or amphetamine salts (Adderall) at 10 mg once daily in the morning, then titrate upward by 5–10 mg weekly until symptoms are controlled or dose-limiting side effects appear. 1

Evidence-Based Starting Doses by Medication Class

Methylphenidate

• Start at 5 mg three times daily (after breakfast, lunch, and mid-afternoon) for immediate-release formulations 1
• For extended-release formulations such as OROS-methylphenidate (Concerta), begin at 18 mg once daily in the morning, which is equivalent to methylphenidate 5 mg three times daily 2
• The therapeutic range for adults is 5–20 mg three times daily for immediate-release or up to 60 mg daily maximum for extended-release products 1, 3

Amphetamine-Based Stimulants

• Adderall XR: start at 10 mg once daily in the morning, increase by 5 mg weekly 1, 4
• Lisdexamfetamine (Vyvanse): start at 20–30 mg once daily in the morning, increase by 10 mg weekly 1, 5
• Dextroamphetamine: start at 5 mg three times daily, titrate to 20 mg twice daily maximum 1
• The therapeutic range for amphetamine salts is 10–50 mg daily, with a maximum of 50 mg for Adderall XR in adults 1, 4

Systematic Titration Protocol

The key principle is systematic dose optimization rather than weight-based dosing. Approximately 70% of patients achieve optimal response when proper titration protocols are followed, independent of body weight calculations 1

Weekly Titration Steps

• Increase by 5–10 mg weekly for immediate-release methylphenidate or amphetamine salts 1, 3
• Increase by 18 mg weekly for OROS-methylphenidate (Concerta) 2
• Increase by 10 mg weekly for lisdexamfetamine 5
• Continue titration until ADHD symptoms are optimally controlled or dose-limiting adverse effects appear 1

Response Assessment

• Stimulants work within days, allowing rapid assessment of efficacy at each dose level 1
• Obtain weekly symptom ratings during dose adjustment using standardized ADHD rating scales 1, 4
• Approximately 70–80% of adults respond when stimulants are properly titrated 1, 6

Critical Monitoring Parameters

Baseline Assessment

• Measure blood pressure and pulse before starting any stimulant 1, 7
• Obtain a detailed cardiac history including syncope, chest pain, palpitations, and family history of premature cardiovascular death 1
• Screen for contraindications: symptomatic cardiovascular disease, uncontrolled hypertension, active psychosis, hyperthyroidism, glaucoma, or concurrent MAOI use 1

Ongoing Monitoring During Titration

• Check blood pressure and pulse at each dose adjustment 1, 7
• Monitor for common adverse effects: decreased appetite, insomnia, headache, and irritability 1, 8
• Track sleep quality and appetite changes throughout therapy 1
• In adults, continue quarterly blood pressure and pulse checks during maintenance 1

Expected Cardiovascular Effects

• Stimulants increase systolic blood pressure by approximately 1.9 mmHg and diastolic blood pressure by 1.8 mmHg 9
• Heart rate increases by approximately 3.7 beats per minute 9
• New-onset hypertension (≥140/90) occurs in approximately 10% of treated adults 7

Common Pitfalls to Avoid

Do not underdose. The most common error is stopping titration prematurely at subtherapeutic doses 1. Community treatment programs using lower doses and less frequent monitoring produce inferior outcomes compared with optimal, closely monitored medication management 1

Do not rely on mg/kg dosing. Response variability is not correlated with height or weight; systematic titration to the lowest effective dose that yields clinical benefit is preferred 1

Do not assume treatment failure after one stimulant class. Approximately 40% of patients respond to both methylphenidate and amphetamine, while another 40% respond preferentially to only one class 1. If inadequate response occurs after adequate treatment with one stimulant class, trial the other class before considering non-stimulants 1

Do not add a second medication before maximizing the first. Complete a trial of stimulant monotherapy at an adequate dose before adding adjunctive agents 1

Choosing Between Methylphenidate and Amphetamine

Both classes are equally effective first-line options with 70–80% response rates when properly titrated 1, 6. The choice depends on:

• Duration of action needed: Extended-release amphetamine formulations provide 8–9 hours of coverage, while some methylphenidate ER formulations provide 10–12 hours 3
• Dosing flexibility: Methylphenidate immediate-release allows finer dose adjustments starting at 5 mg, whereas lisdexamfetamine requires a minimum of 20 mg 1
• Individual response: If one class fails after adequate titration, switch to the other class using the same systematic approach 1

Conversion Ratio When Switching Classes

Use a 2:1 conversion ratio (methylphenidate:amphetamine) when switching between classes 3. For example, methylphenidate ER 45 mg converts to approximately Adderall ER 20–25 mg once daily 3. Start at the converted dose and re-titrate based on response 3