Which baseline and follow‑up metabolic laboratory tests (e.g., fasting glucose, hemoglobin A1c, full lipid profile, BMI, blood pressure, serum prolactin, basic metabolic panel, liver function tests, renal function, and TSH) should be ordered for patients starting or receiving psychiatric medications that affect metabolism?

Metabolic Laboratory Panel for Psychiatric Medications

For patients starting or receiving psychiatric medications that affect metabolism, obtain the following baseline tests: BMI, waist circumference, blood pressure, HbA1c, glucose, lipids, prolactin, liver function tests, urea and electrolytes, full blood count, and electrocardiogram. 1

Baseline Assessment (Before Starting Antipsychotic Treatment)

The following measures must be obtained before initiating antipsychotic medication 1:

• Anthropometric measurements: BMI and waist circumference
• Cardiovascular: Blood pressure and electrocardiogram
• Glucose metabolism: HbA1c and glucose (fasting preferred, but random acceptable as initial screen)
• Lipid profile: Complete lipid panel
• Hormonal: Serum prolactin
• Hepatic: Liver function tests (ALT, AST, alkaline phosphatase, GGT)
• Renal: Urea and electrolytes (creatinine, BUN)
• Hematologic: Full blood count

Important Note on Fasting Requirements

Fasting is not routinely required for lipid profiles 2. Non-fasting samples are acceptable for initial screening, with maximal mean changes being clinically insignificant (triglycerides +26 mg/dL, total cholesterol -8 mg/dL, LDL -8 mg/dL). This improves patient compliance. However, if non-fasting triglycerides exceed 440 mg/dL (5 mmol/L), obtain a fasting sample 2.

For glucose testing, if a fasting sample cannot be obtained, use a random glucose as initial screening; if abnormal, prioritize obtaining a fasting measurement 1.

Follow-Up Monitoring Schedule

Early Monitoring (First 6 Weeks)

• Weekly for 6 weeks: BMI, waist circumference, and blood pressure 1
• At 4 weeks: Fasting glucose (or random if fasting not feasible) 1

Intermediate Monitoring (3 Months)

Repeat all baseline measures at 3 months after starting or switching antipsychotic medication 1. This includes:

• BMI, waist circumference, blood pressure
• HbA1c and glucose
• Complete lipid panel
• Prolactin
• Liver function tests
• Urea and electrolytes
• Full blood count

Long-Term Monitoring (Annual)

After the 3-month assessment, repeat all measures annually 1.

Special Considerations for HbA1c

HbA1c is a more stable parameter than fasting glucose for identifying patients with diabetes risk 3. In psychiatric patients on antipsychotics, HbA1c contributes significantly to prediabetes diagnosis (32% of cases) and shows lower conversion rates back to normal compared to fasting glucose-based diagnoses (18% vs 72%), indicating greater stability 3.

Metformin Monitoring (If Prescribed)

When metformin is used adjunctively with high-risk antipsychotics (olanzapine, clozapine), additional monitoring is required 1:

• Before starting: Assess renal function (avoid if renal failure present)
• Ongoing annual monitoring: Liver function, HbA1c, renal function, and vitamin B12

Common Pitfalls to Avoid

1. Don't skip baseline testing: Establishing baseline values is critical for detecting medication-induced metabolic changes
2. Don't rely solely on fasting glucose: HbA1c provides complementary and more stable information about glycemic status 3
3. Don't delay early monitoring: The first 4-6 weeks are critical for detecting rapid metabolic changes, particularly weight gain
4. Don't forget the ECG: Baseline ECG is essential before starting antipsychotics due to QTc prolongation risk 1

Frequency Adjustments

Monitoring frequency should increase based on:

• Presence of baseline risk factors (obesity, family history)
• Specific antipsychotic agent (higher risk with olanzapine, clozapine)
• Time since medication initiation (more frequent when recently started) 4