Diagnostic and therapeutic value of apomorphine in Parkinsonian patients

Abstract

Apomorphine is a dopamine agonist administered subcutaneously for the management of motor symptoms of Parkinson's disease (PD). Patients with Parkinsonian syndrome underwent an apomorphine challenge for therapeutic efficacy, a positive response being a reduction of > 15% score on motor unified PD rating scale. Of the 42 patients, aged 37-81, disease duration 12 months to 20 years, 36 had a positive response. Six non-responders were later diagnosed as non-PD as compared with only two of the 36 responders. Tremor-predominant patients obtained higher motor response. Few patients demonstrated a delayed positive response. Seven (three idiopathic PD (iPD), four non-PD) suffered adverse reactions of nausea, vomiting or ill-sustained symptomatic fall in BP. Majority of the patients who continued with apomorphine therapy were able to reduce levodopa and achieved an improvement in dyskinesia and motor symptoms. Thirteen responding patients were managed by increasing dopamine agonists. Five patients, intolerant of oral dopamine agonists, were able to beneficially tolerate apomorphine. Age and disease duration did not influence tolerability or efficacy. The patients treated with apomorphine were able to significantly reduce the dose of levodopa, and there was a reduction in dyskinesia, hallucinations and fluctuations (all p < 0.05). In some patients, apomorphine prevented admission to institutions. We also describe the use of apomorphine in acutely ill patients unable to ingest oral medication. Apomorphine seems to have a diagnostic element for iPD. Its use leads to a reduction in dyskinesia, improvement in motor symptoms and prevention of institutional care. Apomorphine test also identifies patients likely to benefit with an increase in oral medication. Age and disease duration should not prevent the use of this valuable drug. Apomorphine also has a role in acutely ill PD patients.