What labs and vital signs should be checked before starting Attention Deficit Hyperactivity Disorder (ADHD) medications?

Labs and Vital Signs Before Starting ADHD Medications

Before initiating ADHD medications, obtain baseline blood pressure, pulse, height, and weight in the context of a physical examination—no routine laboratory tests are required unless specific cardiac risk factors are identified. 1

Required Baseline Measurements

Vital Signs (All Patients)

• Blood pressure and pulse must be measured at baseline before starting any ADHD medication, whether stimulant or non-stimulant 1
• Height and weight should be documented to monitor growth effects during treatment 1
• These measurements help identify adolescents and children with malignant hypertension and adults with essential hypertension and/or cardiac arrhythmias 1

Physical Examination Requirements

• A routine physical examination should be completed before starting stimulant medications 1
• The examination should specifically assess for cardiac murmurs or symptoms of heart failure 2

Cardiac History Screening (No Labs Required)

Personal History Elements to Obtain

• Specific cardiac symptoms: exertional chest pain, unexplained syncope, palpitations, or exercise intolerance 2, 3, 4
• Personal cardiac history: known structural heart disease, cardiomyopathy, serious heart rhythm abnormalities, or coronary artery disease 4, 5
• Seizure history: document if seizure disorder is present and whether it is controlled with anticonvulsants 1

Family History Elements to Obtain

• Sudden unexplained death in young family members (especially before age 35-40) 2, 3
• Family history of ventricular arrhythmia 4
• Specific inherited conditions: Wolff-Parkinson-White syndrome, hypertrophic cardiomyopathy, long QT syndrome 3

When Additional Cardiac Evaluation Is Needed

Indications for ECG or Cardiology Referral

• If any cardiac risk factors are present from history or physical examination, obtain additional cardiac evaluation including ECG, possibly echocardiogram, or cardiology referral before starting stimulants 3, 4
• Structural cardiac abnormalities or serious heart problems identified on examination require further evaluation 4, 5
• The American Heart Association previously recommended screening ECGs for all children before stimulant medications, though this was subsequently opposed by the American Academy of Pediatrics 1

Patients Who Can Proceed Without ECG

• Low-risk patients with no cardiac symptoms, negative family history, and normal physical examination can proceed with ADHD medication without routine ECG 2
• Screening ECGs in asymptomatic patients rarely result in management changes (only 0.14% in one community study) 6

No Routine Laboratory Tests Required

Blood Tests Are Not Indicated

• No baseline blood work (such as CBC, metabolic panel, liver function tests, or thyroid tests) is required before starting ADHD medications unless clinically indicated by history or physical examination 1
• Laboratory testing for liver enzymes should only be done if symptoms of liver dysfunction develop (pruritus, dark urine, jaundice, right upper quadrant tenderness, unexplained flu-like symptoms) 4

Exception for Specific Clinical Scenarios

• Urine drug screen may be considered in adults with high rates of comorbid substance abuse before starting stimulant medications 1
• Thyroid function tests may be warranted if hyperthyroidism is suspected clinically, as this is a contraindication to stimulants 5

Special Populations Requiring Caution

Pre-existing Hypertension

• Blood pressure must be well-controlled (target <130/80 mmHg) before initiating ADHD medications 3
• Consider non-stimulant options (atomoxetine, guanfacine, clonidine) as first-line in patients with hypertension 3
• If stimulants are used, more frequent blood pressure monitoring is necessary 3

Known Cardiac Disease

• Patients with structural heart disease (congenital heart disease, cardiomyopathy, significant valvular disease) require cardiology evaluation before starting stimulants 2, 4
• Stimulants should generally not be used in children or adolescents with known serious structural cardiac abnormalities 4
• Adults with clinically significant cardiac abnormalities should be given consideration to not treating with stimulants 4

Common Pitfalls to Avoid

• Do not order routine ECGs in all patients—this is not supported by current evidence and rarely changes management 6
• Do not order comprehensive metabolic panels or other laboratory tests routinely—focus on targeted history and physical examination 1
• Do not skip baseline vital signs—this is the single most important objective measurement needed 1
• Do not forget to document prior treatments—information on previous medications, dosages, duration, response, and side effects should be collected 1

Monitoring Schedule After Initiation

Children and Adolescents

• Vital signs should be checked annually during routine physical examination 1
• Height and weight should be checked often during treatment to monitor growth effects 5

Adults

• Blood pressure and pulse should be checked on a quarterly basis by the treating physician or primary care physician 1
• More frequent monitoring is needed in adults with pre-existing hypertension or cardiovascular disease 3