- On L-dopa treatment. Patient must be on oral L-dopa treatment - with or without dopamine agonist including Apomorphine, MAO-B inhibitor, COMT inhibitor, Amantadine, Beta blocker, anticholinergic treatment History of wearing off phenomena- duration of action of single dose of L-dopa < 6 hours Stable PD medication for preceding 3 months- i.e. no change in medication type or dose.