Combination Therapy with Intravitreal Triamcinolone Acetonide and Oral Levodopa for the Treatment of Nonarteritic Anterior Ischemic Optic Neuropathy: A Pilot Study

Purpose: To determine the clinical effectiveness of combination therapy with intravitreal injection of triamcinolone acetonide (IVITA) and oral levodopa in eyes affected by nonarteritic anterior ischemic optic neuropathy (NAION). Methods: Longitudinal study involving 45 eyes of 45 patients with NAION who were evaluated within 14 days of NAION onset. The treatment group received an IVITA 4 mg/0.1 mL followed by 25 mg carbidopa/100 mg levodopa (Sinemet 25-100) 3 times daily for 12 weeks and the control group was untreated. Best-corrected visual acuity (BCVA) converted to logarithmic minimum angle of resolution (logMAR), visual field (VF) grades based on automated or Goldman perimetry, and mean retinal nerve fiber layer (RNFL) thickness measured on optical coherence tomography were assessed at the initial visit, 1, 3, and 6 months after NAION attack. Results: At the first visit and 6 months after NAION onset, the mean logMAR BCVA in the treatment group was significantly better than the control group (P < 0.05). BCVA was not significantly different between onset and the 6-month visit for both the control and the treatment group; however, the change in BCVA after 6 months was significantly greater in the treatment group compared with the control group (P = 0.007). Concomitant systemic disease, the changes in VF grades, and RNFL thickness from initial to 6 months after NAION onset were not significantly different between 2 groups. Conclusions: Combination therapy with IVITA and oral levodopa/carbidopa appears to be effective in the treatment of recent-onset NAION.

Pharmacokinetics of Rytary®, An Extended-Release Capsule Formulation of Carbidopa-Levodopa

Parkinson's disease (PD) is a chronic progressive neurological disorder characterized by resting tremor, rigidity, bradykinesia, gait disturbance, and postural instability. Levodopa, the precursor to dopamine, coadministered with carbidopa or benserazide, aromatic amino acid decarboxylase inhibitors, is the most effective and widely used therapeutic agent in the treatment of PD. With continued levodopa treatment, a majority of patients develop motor complications such as dyskinesia and motor 'on-off' fluctuations, which are, in part, related to the fluctuations in plasma concentrations of levodopa. A new extended-release (ER) carbidopa-levodopa capsule product (also referred to as IPX066) was developed and approved in the US as Rytary^® and in the EU as Numient^®. The capsule formulation is designed to provide an initial rapid absorption of levodopa comparable to immediate-release (IR) carbidopa-levodopa, and to subsequently provide stable levodopa concentrations with reduced peak-to-trough excursions in plasma concentrations in order to reduce motor fluctuations associated with pulsatile stimulation of dopamine receptors and to minimize dyskinesia. Phase III studies of this ER carbidopa-levodopa capsule formulation in patients with PD have shown a significant reduction in 'off' time compared with IR carbidopa-levodopa and carbidopa-levodopa-entacapone. We present a review of the clinical pharmacokinetics and pharmacodynamics of this ER product of carbidopa-levodopa in healthy subjects and in patients with PD.