Causes of High Prolactin Levels
Causes of high prolactin levels (known as hyperprolactinemia) include such things as pregnancy, breastfeeding, and a prolactinoma or other type of pituitary tumor. Certain medications (such as trifluoperazine) and hypothyroidism are also possible causes of high prolactin levels.
There are a number of possible causes of high prolactin levels (also known as hyperprolactinemia). Some common causes of high prolactin levels include:
- Pregnancy and breastfeeding
- Certain medicines (such as trifluoperazine and haloperidol)
- Other pituitary tumors
- Breast stimulation.
Prolactin stimulates the breast to produce milk during pregnancy. After delivery of the baby, a mother's prolactin levels fall unless she breastfeeds her infant. Each time the baby nurses, prolactin levels rise to maintain milk production.
A prolactinoma is a benign (non-cancerous) tumor of the pituitary gland that produces prolactin. A prolactinoma is the most common type of pituitary tumor. Symptoms of prolactinoma are caused by too much prolactin in the blood (hyperprolactinemia) or by pressure of the tumor on surrounding tissues.
Prolactin secretion in the pituitary is normally suppressed by the brain chemical, dopamine. Drugs that block the effects of dopamine at the pituitary or that deplete dopamine stores in the brain may cause the pituitary to secrete prolactin.
These medicines include:
- The major tranquilizers trifluoperazine (Stelazine®) and haloperidol (Haldol®)
- Metoclopramide (Reglan®), used to treat gastroesophageal reflux disease (GERD) and the nausea caused by certain cancer drugs