What is levodopa?

Given oral, increase DA synthesis, absorbed in GI and crosses BBB, converted to DA in brain. Effects: at periphery conversion to DA leads to GI irritation, stimulation of CTZ, leading to gastric upset w/nausea and vomit. Activation of peripheral Rs also causes orthostatic Hypotension, renal vasodilation, cardiac arrythmias. Dyskinesia (peak L-DOPA concentration leads to abnormal involuntary mvmnt) To increase its crossing to brain we combine it with carbidopa blocks peripheral metabolism. Drug-Drugs interaction: Vit B6, MAI-I cause HTA crisis