[Apomorphine in the treatment of Parkinson's Disease].

Apomorphine has long been used in many medical specialties. It is a highly potent D2-, D3- and D4-dopamine receptor agonist with a particularly high D1-dopamine receptor affinity. Due to its almost complete inactivation during liver passage it is usually applied subcutaneously. After rapid onset its effect is waning after about one hour. Apomorphine's action is not dependent on enteral dopamine resorption and on praesynaptic dopamine storage and dopamine secretion mechanisms. When applied subcutaneously its most common side effect is cutaneous nodules at the injection sites. Peripheral dopaminergic side effects, such as nausea and orthostatic hypotension, usually occur only during therapy initiation and respond well to domperidone. Hallucinations occur less frequently than with other dopamine receptor agonists. The apomorphine test determines the levodopasensitivity of a parkinsonian syndrome by application of an apomorphine bolus to distinguish between idiopathic Parkinson's disease and atypical parkinsonian syndromes. It indicates a levodopasensitivity in about 90% of the patients tested. False-negative results can occur in mild parkinsonian syndromes. A meta analysis indicates that intermittent subutaneous apomorphine applications (intermittent apomorphine therapy) with a self application device can reduce the daily duration of unpredictable off-phases by 48.8+/-8.7%. For this an average of 3.7+/-1.1 x 2.9+/-0.8 mg apomorphine has to be applied per day. Continuous subcutaneous apomorphine application with an extracorporal pump (continuous apomorhine therapy) during the wake phase reduces the duration of daily off-phases by 64.8+/-13.5% and the additional levodopa dose by 30.3+/-31.1%. 24-hour application reduces the daily duration of the off-phases by 63.5+/-19.1% and the additional levodopa dose by 65.5+/-21.9%. Levodopa-induced dyskinesias are also substantially reduced. A gradual conversion to an apomorphine monotherapy is possible. Even after prolonged treatment times no significant loss of efficacy occurs. With this profile apomorphine is a highly successful treatment option for off-phases and levodopa-induced dyskinesias in advanced cases of idiopathic Parkinson's disease which should be used before more invasive approaches are considered.