Serum/plasma concentration of chlorpromazine (antipsychotic drug level)

Why Is This Test Done?

Your doctor may order this test if you’re taking chlorpromazine to manage symptoms like psychosis, aggression, or sleep disturbances. It’s also used to monitor levels in people with certain conditions, such as schizophrenia or bipolar disorder, to avoid side effects like dizziness, weight gain, or movement disorders.

What to Expect Before the Test

No special preparation is needed unless instructed by your doctor. You may have a small needle inserted into your arm or hand to draw blood. If you’re on a long-term medication like chlorpromazine, your doctor might check levels periodically to adjust your dose.

What the Results Mean

Results are typically reported as a concentration in micrograms per milliliter (mcg/mL). While reference ranges vary by lab, low levels may indicate insufficient medication, while very high levels could signal toxicity or improper metabolism.

Common Reasons for Testing

Doctors may order this test if you’re new to chlorpromazine, experiencing unusual symptoms (like confusion or rapid heartbeat), or if your dose needs adjustment. It’s also used in cases of suspected overdose or drug interactions.