Adverse drug reaction suggested by a clinical vignette

Abstract

I had a three-lobe pneumonia and toxic encephalopathy in 2004. A lumbar puncture did not show meningitis. Magnetic resonance imaging showed a macroadenoma of the pituitary gland. Prolactin level was significantly elevated, making the diagnosis a functioning prolactinoma requiring treatment. Initially, I was treated with the dopamine agonist cabergoline, which is also used in much larger doses to treat Parkinsonism. Recent reports have indicated heart valve damage in Parkinsonism patients treated with ergot-derived dopamine-receptor agonists.1,2 In his monumental book The Pituitary, Shlomo Melmed states that patients with this clinical problem who are taking cabergoline should be informed of the potential risk of heart valve damage and have a cardiac echo if they have an audible heart murmur. They can then continue their current medication or switch to bromocriptine, which has a lower risk.3 Norprolac (quinagolide), which can be obtained from England via Canada, is a well-tolerated alternative that controls the prolactin level and does not have the same risks as dopamine-receptor agonists. I am a retired geriatrician, with considerable experience in restless legs syndrome. This syndrome is not uncommon in the elderly, although it is not noted in the index of Hazzard’s Geriatric Medicine and Gerontology under this category nor under sleep disorders.4 The problem is treated with the dopamine agonists ripinirole and prampexole. Is it possible that lurking in this treatment is the potential for heart valve damage?