Wednesday, May 20, 2009

Got Milk?

A 25 year old woman with a new diagnosis of schizophrenia is started on risperidone. She then presents complaining of galactorrhea.

Challenge: What is the mechanism by which risperidone causes galactorrhea?

Image shown under fair use.

3 comments:

tree said...

Dopamine antagonism "inhibits the inhibition" on prolactin secretion.

Stephanie said...

risperidone is antidopiminergic, therefore it suppresses dopamine, which normally suppresses prolactin. increased prolactin leads to galactorrhea.

Craig Chen said...

You guys know the basic science way better than I do :)
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Got Milk?

Risperidone is an atypical antipsychotic with mixed serotonin-dopamine antagonist activity. Dopamine in the CNS acts as an antagonist to prolactin secretion; thus, the anti-dopaminergic activity leads to increased prolactin and galactorrhea.

Sources: UpToDate; Wikipedia.