Repeated-Dose Oral N-Acetylcysteine in Parkinson's Disease: Pharmacokinetics and Effect on Brain Glutathione and Oxidative Stress.
ncbi.nlm.nih.gov/pubmed/289...
To characterize the pharmacokinetics of repeated high oral doses of NAC and their effect on brain and blood oxidative stress measures, we conducted a 4-week open-label prospective study of oral NAC in individuals with PD (n = 5) and in healthy controls (n = 3).
Brain GSH was measured in the occipital cortex using 1 H-MRS at 3 and 7 tesla before and after 28 days of 6000 mg NAC/day.
Blood was collected prior to dosing and at predetermined collection times before and after the last dose to assess NAC, cysteine, GSH, catalase, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) concentrations and the reduced-to-oxidized GSH ratio (GSH/ glutathione disulfide [GSSG]).
Symptomatic adverse events were reported by 3 of the 5 subjects with PD. NAC plasma concentration-time profiles were described by a first-order absorption, 1-compartment pharmacokinetic model.
Although peripheral antioxidant measures (catalase and GSH/GSSG) increased significantly relative to baseline, indicators of oxidative damage, that is, measures of lipid peroxidation (4-HNE and MDA) were unchanged.
There were no significant increases in brain GSH, which may be related to low oral NAC bioavailability and small fractional GSH/GSSG blood responses.
Additional studies are needed to further characterize side effects and explore the differential effects of NAC on measures of antioxidant defense and oxidative damage.