APOMORPHINE HYDROCHLORIDE, HAS BEEN KNOWN SINCE THE 1960S TO BE EFFECTIVE IN PARKINSON'S DISEASE.
Apomorphine is currently the only approved acute, intermittent treatment to turn patients ON and provide rapid relief from OFF episodes (Apokyn® in the United States and ApoGo®, ApokinON® or Apomin® outside the United States). Apomorphine is the most potent and fast-acting of all the dopamine agonists, which are used to stimulate dopamine receptors in place of naturally released dopamine, with similar efficacy to levodopa. No other dopamine agonist is potent enough to turn a levodopa-requiring patient from the OFF state to the ON state in which normal motor function is restored. Apomorphine is currently only available in the United States as a subcutaneous injection. Injectable apomorphine is painful to use, and administration is complex and inconvenient, requiring in excess of 15 steps. It is difficult for a PD patient to use injectable apomorphine while they are in the OFF state, and often requires administration by a caregiver. The injection may also cause scarring (nodules), irritation and injection site reactions. As a result, despite its highly efficacious profile, the adoption of injectable apomorphine has been limited.