Levodopa-Induced Diphasic Dyskinesias Improved by Subcutaneous Apomorphine
To the Editor: Levodopa-induced dyskinesias frequently complicate chronic levodopa therapy in patients with Parkinson's disease (1-3). They can be categorized as "peak-dose" dyskinesias (2), "off-period dystonias" (4), and "onsetand end-of-dose dyskinesias" (2,4). The latter, also called "diphasic dyskinesias," are the least common but the most disabling, especially in young patients. They can last from a few minutes to >1 h. In some patients, increasing the levodopa dosage can lessen diphasic dyskinesias (9, but only during a short period, and with a risk of worsening "peak-dose dyskinesias." Interestingly, Duby et al. reported that single injections of apomorphine, a direct dopaminergic agonist of short duration, improved involuntary movements induced by levodopa, in some patients (6). Therefore, we tried to administer bolus subcutaneous injections of apomorphine as soon as a phase of "diphasic dyskinesias" occurred.
We studied three patients, all women ages 54, 36, and 59 years, who had Parkinson's disease for 12, 8, and 15 years, respectively, and who were treated by levodopa for 11, 5, and 14 years. They presented an akineto-rigid form of the disease, complicated by distressing "diphasic dyskinesias" with severe "onset-of-dose" mobile dystonia affecting the lower limbs. All attempts at drug rnodification had been unsuccessful. The usual oral dose of levodopa plus dopa-decarboxylase inhibitor and domperidone, and antiemetic, were given in the morning. As soon as dyskinesias appeared, a subcutaneous injection of either placebo or apomorphine 1% (Aguettant, Lyon, France) was administered in the abdominal wall. The study was carried out in a simple-blind design for patient 1 and double-blind design for patients 2 and 3. The dose of