Aripiprazole Reduces Serum Prolactin in a Woman with Prolactinoma and Acute Psychosis

Hyperprolactinemia is a common side effect when treating schizophrenic patients with conventional as well as second generation antipsychotics. Highly potent dopamine D₂-receptor antagonistic antipsychotics such as risperodone [4] can cause severe serum prolactin elevations [1] by reversing dopaminergic inhibition and may be associated with a higher rate of pituitary gland tumours [5]. Aripiprazole as a partial D₂-receptor agonist [2] could be useful in the treatment of antipsychotic-induced prolactinemia as it has been shown to produce significant reductions of serum prolactin levels [3].

Ms. K., a 39-year-old, single woman from Kazakhstan, was admitted to the hospital with acute psychotic symptoms including auditory hallucinations, paranoid delusions, psychomotor agitation, sleeplessness and disorganized thoughts. There had been no history of psychiatric illness to this date. She denied thoughts of suicide. Ms K. had noticed a decline of sight of her left eye and left visual field three years prior to admission. The MRI of her brain in 2003 reported a pituitary gland adenoma with a degree of optic chiasm compression. She had been treated with the dopamine agonist bromocriptine (2.5 mg) but ceased to take her medicine two months before the psychotic episode. On admittance, laboratory results revealed a serum prolactin level of 39160 mU/L. An additional MRI showed no progression of the tumour. Ms K. did not have galactorrhea or mastopathy but reported missing her menses for a couple of weeks. Risperidone (2 mg) was administered for one week but then switched to aripiprazole because of the contraindication.

Under risperidone and bromocriptine, which had been continued on admission, serum prolactin was still elevated to 9400 mU/L. The treatment with aripiprazole (15 mg) and bromocriptine (2.5 mg) daily led to a complete remission of psychotic symptoms and better sleep. On discharge four weeks after admission, the serum prolactin level was normalized to 159 mU/L.

This case is not conclusive in part because of the use of bromocriptine. However, the rapidity and degree of serum prolactin reduction weigh in favour of a strong role for aripiprazole. On the basis of this case report, further use of aripiprazole may be warranted in the treatment of patients with pituitary gland tumours suffering from psychosis and patients with antipsychotic-induced hyperprolactinemia.

References

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