What labs should be ordered before starting psychostimulants, such as methylphenidate (Ritalin) or amphetamines?

Laboratory Monitoring Before Starting Psychostimulants

Obtain baseline blood pressure, pulse, height, and weight in the context of a physical examination before initiating psychostimulant therapy. 1

Essential Baseline Assessments

Vital Signs and Physical Measurements

• Blood pressure and pulse must be measured to identify uncontrolled hypertension or cardiac arrhythmias that would contraindicate stimulant use 1
• Height and weight should be documented to calculate body mass index (BMI) and establish a baseline for monitoring growth and weight changes 1
• These measurements help identify adolescents and children with malignant hypertension and adults with essential hypertension before medication exposure 1

Physical Examination Requirements

• A complete physical examination is mandatory before starting stimulants, with particular attention to cardiovascular and neurologic systems 1
• The examination should specifically assess for underlying coronary artery disease and tachyarrhythmias, as methylphenidate and dextroamphetamine must be avoided in patients with these conditions 1

Laboratory Testing: Not Routinely Required

No routine laboratory tests are mandated before initiating psychostimulants in otherwise healthy patients. 1

The 2002 American Academy of Child and Adolescent Psychiatry practice parameter does not recommend baseline laboratory screening for stimulant initiation 1. This contrasts sharply with other psychotropic medications:

• Lithium requires complete blood counts, thyroid function tests, urinalysis, BUN, creatinine, serum calcium, and pregnancy testing 1
• Valproate requires liver function tests, complete blood counts, and pregnancy testing 1
• Antipsychotics require extensive metabolic monitoring including fasting glucose, lipid panels, HbA1c, and ECG 2

When to Consider Additional Testing

Cardiac Evaluation

• ECG is not routinely required but should be obtained if there is personal or family history of cardiac disease, syncope, palpitations, or sudden cardiac death 1
• Patients with known cardiovascular disease require pre-treatment ECG with routine follow-up 3

Pregnancy Testing

• Pregnancy testing should be performed in female adolescents of childbearing age, as this is standard practice before initiating any psychotropic medication 1

History-Directed Testing

• Laboratory testing should be guided by history and physical examination findings rather than a predetermined battery of tests 1
• If the history or physical examination reveals abnormalities suggesting metabolic, endocrine, or other medical conditions that could present as psychiatric symptoms, appropriate targeted testing should be performed 1

Common Pitfalls to Avoid

• Do not order routine urine drug screens before stimulant initiation unless clinically indicated by history; routine toxicology screening has minimal utility and does not change management in most cases 1
• Do not confuse stimulant monitoring with antipsychotic monitoring protocols—the extensive metabolic laboratory panels required for antipsychotics are not applicable to stimulants 2, 4
• Do not delay treatment to obtain unnecessary laboratory work in patients with normal physical examinations and no concerning history 1

Ongoing Monitoring Schedule

After initiation:

• Children and adolescents should have vital signs checked annually during routine physical examinations 1
• Adults on stimulants should have blood pressure and pulse checked quarterly by the treating or primary care physician 1
• Weight monitoring should occur at regular intervals to detect appetite suppression effects 1