Brocresine, an aromatic L-amino acid decarboxylase inhibitor with both a peripheral and central action was shown to potentiate the therapeutic effect of levodopa in Parkinson's disease.

Budipine is an antiparkinsonian drug, which was developed by Byk Gulden (now Takeda) for the treatment of Parkinson's disease. The drug has multiple mechanisms of action: it was found to interfere with dopamine biosynthesis, mainly by inhibiting MAO-B enzyme and stimulating aromatic L-amino acid decarboxylase. Also the drug inhibits the dopamine re-uptake and has weak affinity to NMDA and muscarinic receptors. Budipine passes the blood-brain barrier, is metabolized by hydroxylation, and is excreted by both in urine and feces within 24 h.

Oxitriptan is an aromatic amino acid with antidepressant activity. In vivo, oxitriptan is converted into 5-hydroxytryptamine (serotonin) as well as other neurotransmitters. Oxitriptan may exert its antidepressant activity via conversion to serotonin or directly by binding to serotonin receptors within the central nervous system. It is used as an antiepileptic and antidepressant. Oxitriptan is a worthwhile addition to the limited treatments available for obsessive-compulsive disorder and panic disorder, two psychiatric disorders which have previously been difficult to manage pharmacologically. Possible gastrointestinal side effects are: nausea, vomiting, abdominal pain, constipation or flatulence, which tend to disappear with continued treatment or, in any case, dose reduction. Other undesirable effects such as anorexia, xerostomia, tachycardia, extrasystoles, dizziness, headache, lightheadedness, tremor or myalgia may occur.

Budipine is an antiparkinsonian drug, which was developed by Byk Gulden (now Takeda) for the treatment of Parkinson's disease. The drug has multiple mechanisms of action: it was found to interfere with dopamine biosynthesis, mainly by inhibiting MAO-B enzyme and stimulating aromatic L-amino acid decarboxylase. Also the drug inhibits the dopamine re-uptake and has weak affinity to NMDA and muscarinic receptors. Budipine passes the blood-brain barrier, is metabolized by hydroxylation, and is excreted by both in urine and feces within 24 h.