title: Positive prolactin response to bromocriptine in 2 patients with cabergoline-resistant prolactinomas.
abstract: OBJECTIVE
  To describe a positive prolactin response to bromocriptine treatment in 2 patients with cabergoline-resistant prolactinomas.
  
  
  METHODS
  We report the patients' clinical presentations, laboratory test results, imaging findings, and clinical courses.
  
  
  RESULTS
  Patient 1 had a 5-mm pituitary microadenoma that was initially diagnosed at age 30 years. After initial diagnosis, she was treated with transvaginal bromocriptine for 9 years and then subsequently went untreated for 2 years. After developing symptoms of amenorrhea, decreased libido, and hyperprolactinemia, oral cabergoline, 0.5 mg twice weekly, was initiated. Her prolactin concentration remained elevated at 80 ng/mL while taking cabergoline. Her prolactin concentration decreased to 13 ng/mL after her regimen was switched to bromocriptine, 5 mg daily. Patient 2 had a 17-mm pituitary macroadenoma that was initially diagnosed at age 15 years. Oral cabergoline was started at 0.5 mg twice weekly and increased to 1 mg 3 times weekly when prolactin levels continued to rise to 340 ng/mL over 18 months. After visual field defects developed, transsphenoidal surgery was performed. One year after surgery, magnetic resonance imaging showed a 6- to 7-mm pituitary adenoma, and there was a gradual rise in serum prolactin. Her serum prolactin concentration continued to rise to 212 ng/mL with increasing tumor size over 3 years. Cabergoline was discontinued and oral bromocriptine was initiated at a dosage of 10 mg daily. After 4.5 months of bromocriptine therapy, her serum prolactin concentration decreased to 133 ng/mL. However, after 2 months, the macroadenoma continued to increase in size and a visual field defect developed, so another transsphenoidal operation was performed.
  
  
  CONCLUSIONS
  Although cabergoline is generally preferred to bromocriptine for the treatment of patients with prolactinomas because of its better tolerance profile and greater effectiveness, in patients with cabergoline-resistant prolactinomas, a bromocriptine trial should be considered a safe, relatively inexpensive, and well-tolerated alternative.
authors.affiliation: Department of Pediatrics, Diabetes, and Metabolism, University of South Florida, Tampa, FL, USA. iyerp@allkids.org
authors.forename: Pallavi
authors.initials: P
authors.lastname: Iyer
authors.forename: Mark E
authors.initials: ME
authors.lastname: Molitch
mesh_terms: D000293:Adolescent; D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001971:Bromocriptine / Q000627:therapeutic use*; D000077465:Cabergoline; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004873:Ergolines / Q000627:therapeutic use*; D005260:Female; D006727:Hormone Antagonists / Q000627:therapeutic use; D006801:Humans; D010911:Pituitary Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D015175:Prolactinoma / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D004873:Ergolines; D006727:Hormone Antagonists; D001971:Bromocriptine; D011388:Prolactin; D000077465:Cabergoline