First used as a treatment for Parkinson's disease as early as 1951,[4] its clinical use was first reported in 1970 by Cotzias et al.,[5] although its emetic properties and short half-life made oral use impractical. A later study found that combining the drug with the antiemetic domperidone improved results significantly.[6] The commercialization of apomorphine for Parkinson's disease followed its successful use in patients with refractory motor fluctuations using intermittent rescue injections and continuous infusions.[7]
Therapeutic use in Parkinson's disease is effective because of the drug's strong dopaminergic action. When administered subcutaneously, apomorphine is the most effective dopamine agonist. Within 3–20 minutes of injection apomorphine demonstrates a magnitude of effect (ability to convert the patient with Parkinson's disease to the "on" state) that is comparable to l-dopa. A single subcutaneous injection lasts for up to 90 minutes.[8] While apomorphine can be used in combination with l-dopa, the intention is usually to reduce the l-dopa dosing, as by this stage the patient with Parkinson's disease will probably be experiencing a great deal of dopa-induced dyskinesias and "off" periods.[8] Following a successful apomorphine challenge, training of patient and caregiver, and careful dose titration, the patient can be maintained in the "on" state by the use of an apomorphine pump as an effective monotherapy.[8]