Which parameter is routinely monitored for patients on olanzapine?

• A. Blood pressure
• B. Creatinine clearance
• C. Liver enzymes
• D. Prolactin

Answer: (D)

Prolactin is monitored because antipsychotics block dopamine D2 receptors, and a key effect of this blockade is increased prolactin release from the pituitary. Olanzapine can cause hyperprolactinemia, though the effect is typically less pronounced than with some other antipsychotics, it can still occur, especially at higher doses. Detecting elevated prolactin helps identify potential clinical consequences such as menstrual disturbances, galactorrhea, sexual dysfunction, and bone health implications. While metabolic monitoring (weight, glucose, lipids) is also important with olanzapine, prolactin specifically reflects the drug’s endocrine impact and is why it is routinely considered in safety monitoring.