[Apomorphine in off state--clinical experience].Neurol Neurochir Pol. 2007 Mar-Apr; 41(2 Suppl 1):S40-8.NN
Apomorphine, a non-ergot derivative, is a potent, directly acting dopamine receptor agonist with high affinity to D4, lower to D2, D3, D5, the lowest to D1-like dopamine receptors as well as to serotonin and adrenoreceptors. Subcutaneous apomorphine is currently used in Parkinson's disease as an add-on to levodopa therapy or monotherapy for management of sudden, unexpected and refractory to levodopa-induced off state and fluctuation in advanced stage of illness. Many clinical trials have shown markedly (about 50-72%) reduced time of off phases. Other indications include the challenge test for determining the dopaminergic responsiveness. Apomorphine is used subcutaneously either as intermittent rescue injections or continuous infusions. Several other routes - transdermal, sublingual, intranasal, rectal and intravenous infusion - have been tried. Oral administration is not recommended. Apomorphine has rapid onset of antiparkinsonian action, qualitatively comparable to that of levodopa, short duration of action and stable efficacy with usually mild adverse events similar to other dopamine agonists. Domperidone or trimethobenzamide should be introduced before starting apomorphine treatment to reduce occurrence of peripheral adverse events (nausea, vomiting, orthostatic hypotension). Dyskinesias, sleep disturbances, hallucinations, delusion, oedema and yawning can occur, but some side effects are connected only with a specific route (for example skin nodules appearing during subcutaneous administration). Despite its long history, apomorphine is registered and used in only a few countries. Apomorphine warrants wider application in treatment of advanced Parkinson disease but the high cost of the drug, the necessity of concomitant treatment for prevention of side effects and subcutaneous administration restrict its use.