Carbidopa dosage modifies L-dopa induced side effects and blood levels of L-dopa and other amino acids in advanced parkinsonism.
Thirty-four patients with advanced Parkinson's disease showing intolerance to therapeutic doses of L-DOPA were treated with L-DOPA plus carbidopa at two different proportions. Ten patients preferred medication containing 10% carbidopa while 24 preferred 25% carbidopa. The increase of carbidopa reduced gastrointestinal disturbances and psychiatric side effects related to L-DOPA, but improvement of disability when measured according to objective tests was modest. Higher doses of carbidopa reduced peripheral DOPA metabolism and increased blood levels of tryptophan, 3-OM-DOPA and DOPA in relation to the administered dose.
D000368:Aged; D002230:Carbidopa / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D005260:Female; D006719:Homovanillic Acid / Q000097:blood; D006801:Humans; D007700:Kinetics; D007980:Levodopa / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood / Q000188:drug therapy*; D014364:Tryptophan / Q000097:blood; D014443:Tyrosine / Q000097:blood
D014443:Tyrosine; D007980:Levodopa; D014364:Tryptophan; D002230:Carbidopa; D006719:Homovanillic Acid