What baseline labs should be ordered when initiating Invega (paliperidone) injection?

Baseline Laboratory Testing for Invega (Paliperidone) Injection

Before initiating Invega injection, obtain a complete blood count (CBC) with differential and a comprehensive metabolic panel (CMP) including liver function tests (ALT, AST, alkaline phosphatase, bilirubin) to establish baseline hematologic and hepatic parameters. 1

Essential Baseline Laboratory Tests

Core Metabolic and Hematologic Assessment

• Complete Blood Count (CBC) with differential is required to establish baseline hematologic parameters before starting paliperidone 1
• Comprehensive Metabolic Panel (CMP) should be obtained, including:
  • Liver function tests (ALT, AST, alkaline phosphatase, bilirubin) to screen for pre-existing liver disease 1
  • Electrolytes, blood urea nitrogen, and creatinine to assess renal function 2
  • Glucose level for metabolic screening 2

Additional Recommended Baseline Tests

• Fasting lipid profile (total cholesterol, LDL, HDL, triglycerides) should be obtained to assess baseline cardiovascular risk, as antipsychotics can affect lipid metabolism 2
• Hemoglobin A1C is recommended to screen for diabetes and prediabetes, particularly important given the metabolic effects of antipsychotics 2
• Pregnancy testing in individuals of childbearing potential before starting treatment 3

Critical Pre-Treatment Clinical Assessment

Physical Examination Requirements

• Baseline physical examination to document any pre-existing abnormal movements is essential before starting antipsychotics to avoid later mislabeling them as medication side effects 1
• This documentation is crucial because paliperidone can cause extrapyramidal symptoms, and distinguishing pre-existing from treatment-emergent movement disorders is clinically important 4, 5

Cardiovascular Considerations

• Baseline ECG should be considered, as paliperidone is associated with modest QTc interval prolongation 4, 5
• Blood pressure measurement at baseline is recommended 2

Important Clinical Context

Why These Tests Matter

Unlike some other psychiatric medications, paliperidone does not require as extensive baseline laboratory testing as immunosuppressants or other high-risk medications 1. However, the tests listed above are critical because:

• Metabolic monitoring is essential: Paliperidone, like other atypical antipsychotics, can affect glucose and lipid metabolism 5
• Hepatic function matters: While paliperidone undergoes minimal hepatic metabolism compared to risperidone, baseline liver function helps interpret any subsequent abnormalities 1, 6
• Movement disorder documentation prevents misattribution: Extrapyramidal symptoms are dose-related with paliperidone, and baseline documentation is your medicolegal protection 4, 5

Common Pitfalls to Avoid

• Failure to obtain baseline laboratory tests leads to difficulty interpreting subsequent abnormalities 1
• Neglecting to document pre-existing movement disorders results in these being misattributed to medication side effects later 1
• Missing baseline prolactin levels: While not universally required, consider baseline prolactin in patients at risk for prolactin-related complications, as paliperidone significantly elevates prolactin levels 4, 5

What You Don't Need at Baseline

Paliperidone does not require the extensive monitoring needed for medications like clozapine (no mandatory ANC monitoring), lithium (no thyroid/renal baseline required unless clinically indicated), or valproate (no platelet count required) 1. The streamlined approach reflects paliperidone's relatively favorable safety profile compared to first-generation antipsychotics and some other second-generation agents.