Laboratory Monitoring for Patients Taking Antipsychotics
Before starting any antipsychotic medication, obtain a comprehensive baseline metabolic panel including BMI, waist circumference, blood pressure, HbA1c, fasting glucose, lipid profile, prolactin, liver function tests, urea and electrolytes, full blood count, and electrocardiogram. 1, 2
Baseline Laboratory Testing
Required for All Antipsychotics
- BMI and waist circumference to establish baseline weight status 1, 2
- Blood pressure measurement 1, 2
- Fasting glucose or HbA1c to screen for diabetes risk 1, 2, 3
- Complete lipid panel (total cholesterol, LDL, HDL, triglycerides) 1, 2, 3
- Complete blood count (CBC) 1, 2
- Comprehensive metabolic panel including liver function tests, urea, and electrolytes 1, 2
- Electrocardiogram (ECG) to assess QTc interval 1, 2
- Prolactin level 1, 2
- Pregnancy test in women of childbearing age 1, 2
Additional Baseline Tests for Specific Antipsychotics
For clozapine specifically, the FDA mandates additional monitoring due to severe neutropenia risk 3:
- Absolute neutrophil count (ANC) must be obtained before initiating treatment 3
- Baseline serum potassium and magnesium levels due to QTc prolongation risk 3
For lithium (when used with antipsychotics in bipolar disorder) 1:
- Thyroid function tests (TSH, T4)
- Urinalysis
- Blood urea nitrogen and creatinine
- Serum calcium
For valproate (when combined with antipsychotics) 1:
- Baseline liver function tests
- Complete blood count
- Pregnancy test
Follow-Up Monitoring Schedule
First 6 Weeks After Initiation
- Weight/BMI and waist circumference: Check weekly for 6 weeks 1
- Blood pressure: Check weekly for 6 weeks 1
- Fasting glucose: Recheck at 4 weeks after initiation 1
At 3 Months
Repeat all baseline measurements 1, 2:
- BMI and waist circumference
- Blood pressure
- Fasting glucose or HbA1c
- Complete lipid panel
- Liver function tests
- Urea and electrolytes
- Full blood count
- Prolactin level
Annual Monitoring (After Initial 3 Months)
All patients on long-term antipsychotics require annual assessment 1, 2:
- BMI and waist circumference
- Blood pressure
- HbA1c
- Fasting glucose
- Complete lipid panel
- Prolactin
- Liver function tests
- Urea and electrolytes
- Full blood count
- ECG (especially for patients on haloperidol or other high-risk agents) 1
Clozapine-Specific Monitoring
Clozapine requires the most intensive monitoring due to agranulocytosis risk 1, 3:
- ANC monitoring: Weekly for first 6 months, then every 2 weeks for next 6 months, then monthly thereafter if counts remain normal 3
- Electrolytes (potassium, magnesium): Periodically monitor and correct abnormalities 3
- ECG monitoring: Discontinue if QTc exceeds 500 msec 3
Lithium-Specific Monitoring (When Combined with Antipsychotics)
Once stable lithium dose is achieved 1:
- Lithium levels every 3-6 months
- Renal function (BUN, creatinine) every 3-6 months
- Thyroid function tests every 3-6 months
- Urinalysis every 3-6 months
Valproate-Specific Monitoring (When Combined with Antipsychotics)
After achieving therapeutic dose 1:
- Serum valproate levels every 3-6 months
- Liver function tests every 3-6 months
- Complete blood count every 3-6 months
High-Risk Populations Requiring More Frequent Monitoring
Patients with Pre-existing Diabetes or Prediabetes
These patients require more intensive glucose monitoring 1, 2:
- Check fasting glucose or HbA1c more frequently than standard schedule
- Monitor for symptoms of hyperglycemia (polydipsia, polyuria, polyphagia, weakness) 3
Patients Starting Olanzapine or Clozapine
These agents carry the highest metabolic risk 1, 2, 3:
- Consider adjunctive metformin prophylactically 1
- If metformin is used, monitor renal function, HbA1c, and vitamin B12 annually 1, 2
Patients on Haloperidol or First-Generation Antipsychotics
Monitor for extrapyramidal symptoms and cardiac effects 1, 2:
- Regular assessment for tardive dyskinesia, dystonia, akathisia, and parkinsonism 1, 2
- ECG monitoring for QTc prolongation, especially with cardiovascular risk factors 1, 2
- Prolactin levels due to high risk of hyperprolactinemia 2
Critical Safety Monitoring
QTc Prolongation Monitoring
All antipsychotics can prolong QTc interval 1, 3:
- Obtain baseline ECG before starting treatment 1, 2
- Discontinue antipsychotic if QTc exceeds 500 msec 3
- Monitor electrolytes (potassium, magnesium) and correct abnormalities before and during treatment 3
- Be especially vigilant when combining with other QTc-prolonging medications 1, 3
Metabolic Syndrome Monitoring
Antipsychotics, particularly olanzapine and clozapine, significantly increase cardiometabolic risk 1, 2, 3:
- If fasting glucose cannot be obtained, use random glucose as initial screening, then obtain fasting sample if abnormal 1
- Monitor for categorical increases: normal glucose (<100 mg/dL) to high (≥126 mg/dL), or borderline (100-125 mg/dL) to high 3
- Track lipid changes: increases of ≥40 mg/dL in total cholesterol or ≥50 mg/dL in triglycerides warrant intervention 3
Hyperprolactinemia Monitoring
Haloperidol and first-generation antipsychotics cause significant prolactin elevation 2:
- Monitor prolactin levels at baseline and periodically
- Assess for symptoms: galactorrhea, amenorrhea, sexual dysfunction, gynecomastia
- Consider switching to a D2 partial agonist (aripiprazole) if symptomatic 1
Common Pitfalls to Avoid
- Do not rely solely on periodic lab monitoring to detect adverse effects—educate patients about presenting symptoms of metabolic complications, as abnormalities may develop between scheduled tests 1
- Do not use non-fasting lipid panels as sole screening tool, as postprandial testing may reveal abnormalities not apparent in fasting samples 2
- Do not forget pregnancy testing in women of childbearing age before initiating antipsychotics 1, 2
- Do not initiate clozapine without ensuring routine laboratory monitoring is available and sustainable 1
- Do not combine multiple QTc-prolonging medications without careful ECG monitoring and electrolyte management 1, 3