SUBLINGUAL APOMORPHINE - A NEW PHARMACOLOGICAL APPROACH IN PARKINSONS-DISEASE

Apomorphine; a potent dopamine agonist with mixed D1 and D2 properties , has long been recognized to have antiparkinsonian effect. Its oral a dministration is limited by both its hepatic first pass metabolism and adverse side effects (nausea, vomiting, azotemia). It is now widely u sed by subcutaneous route for the treatment of severe ''off'' periods seen with levodopa treatment. However, the use of penjects can be diff icult in some patients with severe tremor or akineto-rigid symptoms du ring ''off'' periods. Our group has recently investigated the effect o f sublingual administration of apomorphine in patients suffering from Parkinson's disease. Sublingual apomorphine was shown to reduce extrap yramidal symptoms. The main characteristics of the pharmacodynamic eff ects of sublingual apomorphine in parkinsonians and the relationship b etween pharmacodynamic and pharmacokinetic effects are discussed. Subl ingual apomorphine has the advantage of being easier to administer tha n subcutaneous injection. For the moment, the long-term use of subling ual apomorphine is limited by two major problems: first, time for diss olution and switch ''on'' (which is longer than after subcutanous rout e) and secondly, the occurrence of local side effects (stomatitis). Fu rther clinical studies using either more efficient (tablets with faste r dissolution) and better tolerated sublingual formulations or other d opamine agonists should be carried on before recommending this approac h in the treatment of Parkinson's disease.