SFEBES2009 Poster Presentations Pituitary (65 abstracts)
Kings College Hospital, London, UK.
Introduction: Hyperprolactinaemia associated with antipsychotic drug use is a commonly encountered clinical problem, yet no decision-making tools exist to guide whether to scan the pituitary gland.
Methods: A 10-year data series was reviewed of 246 patients who were evaluated for prolactin excess with a cannulated prolactin study. All patients had a prolactin drawn immediately following the insertion of a forearm cannula (P1) and a second sample drawn after 120 min bed rest (P2).
Comparison was made between patients with a confirmed microprolactinoma (galactorhoea and/or oligomenorrohea with resting hyperprolactinaemia and microadenoma on MRI) against those on dopamine antagonists as well as normal controls.
The presence of macroprolactin was excluded in all samples.
Results: Sixteen patients out of 246 were on dopamine antagonists. In eight patients the prolactin normalised following discontinuation of the drug for at least 3 weeks.
Number of subjects | P1 (mU/l) | P2 (mU/l) | ΔP (%) | |
Normal controls | 25 | 703.4±35.2 | 347.3±22.7 | −47.2±4.7 |
Microprolactinoma | 54 | 1873.8±179.3‡ | 1718.7±163.9‡ | −4.4±1.6‡ |
Dopamine antagonist use and normal MRI | 6 | 2918.2±672.3‡ | 1588.0±257.5§ | −45.6±9.5*† |
Dopamine antagonist use and microadenoma | 2 | 1201.0±235.0 | 1229.5±270.5 | +1.6±2.4‡ |
*P≤0.001 versus microprolactinoma; †=0.04 versus dopamine antagonist and microadenoma; ‡P≤0.001 versus normal controls; §<0.05 versus normal controls. |
Conclusion: In our series, prolactin normalised after 2 weeks of cessation of dopamine antagonists, when treatment could safely be discontinued. A fall after 2 h rest predicted a normal MRI in patients continuing on dopamine antagonists.