Piroheptine is an antagonist of muscarinic acetylcholine receptors. The drug was used for the treatment of Parkinson's disease, however, it is no longer marketed.

Roxindole (EMD-49,980) is a dopaminergic and serotonergic drug which was originally developed for the treatment of schizophrenia. Roxindole has also been investigated as a therapy for the major depressive disorder, Parkinson's disease, and prolactinoma. Roxindole is dopamine autoreceptor-selective agonistic drug with high affinity to D2-like receptors and with much lower affinities to D1-like, % and ol2, muscarinic and 5HT 2 receptors. Additionally, Roxindole exerts 5HT uptake inhibition and 5HT1A agonistic effects. The bioavailability of Roxindole has been estimated at 5% due to a high first-pass metabolization. On the other hand, in 14C distribution studies, Roxindole has crossed the blood-brain barrier readily and the brain concentrations at all intervals have been much higher than corresponding plasma levels. In clinical trials, Roxindole ‘s antipsychotic efficacy was only modest but it was unexpectedly found to produce potent and rapid antidepressant and anxiolytic effects. However, the clinical development of Roxindole was discontinued.

ARUNDIC ACID (ONO-2506) is an enantiomeric, three carbon atom homolog of valproic acid under development by ONO Pharmaceutical for the potential treatment of stroke, as well as Amyotrophic Lateral Sclerosis and Parkinson's disease. The injectable formulation (Proglia) is finished phase III trials for acute-phase cerebral infarction, and the oral formulation (Cereact) is finished phase II trials in the UK for Alzheimer's disease (AD) and Parkinson's disease (PD). ARUNDIC ACID restores normal astrocyte functions after brain damage by preventing reactive astrocytosis, by activating astrocytic GABAA receptors and suppressing GABA transferase. ARUNDIC ACID inhibits S-100β synthesis in activated cultured astrocytes. This agent has additional antiglutamate and antiinflammatory COX-2 inhibitor properties

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.

Gastrodin is the main bioactive component of Gastrodia elata Blume (G. elata). Tian Ma Su Zhu She Ye (contains Gastrodin) It is an extensively used in the clinical practice of traditional Chinese medicine, to treat neurasthenia, neurasthenia syndrome, angioneurotic headache disorder, traumatic brain syndrome, vertigo meniere disease, medicinal with dizziness, vertigo, sudden deafness, vestibular neuronitis, vertebral basilar artery blood supply deficiency, etc. Apart from traditional claims, scientific reports support the antioxidative, anticonvulsive, antiinflammatory, antiepileptic, antiobesity, anxiolytic, and learning and memory improvements in activities of gastrodin

Piribedil is an antiparkinsonian agent which acts as D2 and D3 receptor agonist. In European countries and worldwide it is used as a monotherapy or in combination with dopatherapy for treatment of Parkinson's disease, cognitive impairment and obliterating arteriopathy.

Lisuride (DOPERGIN®), a highly active dopaminergic ergot derivative with prolactin-lowering properties, has a pronounced affinity for dopamine receptors. It may also act as an agonist at some serotonin receptors. Lisuride (DOPERGIN®) is concentrated within the pituitary where it acts on dopamine receptors which inhibit prolactin release. It can be used in the clinical conditions where a dopaminergic or prolactin-lowering effect is needed.

Acetylcysteine amide (NACA) is a novel thiol-containing antioxidant. NACA is a modified form of its parent compound N-acetylcysteine (NAC) that is a precursor of the most abundant endogenous antioxidant, glutathione (GSH). NACA demonstrated the multiple therapeutic abilities, including antioxidant, anti-apoptotic, and anti-inflammatory properties with greater efficacy compared to its parent compound. NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following spinal cord injury. It is a new neuroprotective drug, that might be effective at slowing down nigral neuronal degeneration and illness progression in patients with Parkinson's disease.

Exifone, a drug recently proposed for the treatment of cognitive deficiencies of old age, has been marketed in France beginning in April 1988. It demonstrated remarkable anti-radical properties, but was withdrawal, because of the hepatotoxicity.

Pitolisant (INN) or tiprolisant (USAN) is a histamine receptor inverse agonist/antagonist selective for the H3 subtype. It has stimulant and nootropic effects in animal studies and may have several medical applications, having been researched for the treatment of narcolepsy, for which it has been granted orphan drug status in the EU and US. It is currently in clinical trials for schizophrenia and Parkinson’s disease. Pitolisant hydrochloride was approved by European Medicine Agency (EMA) on Mar 31, 2016. It was developed and marketed as Wakix® by Bioprojet in EU. Wakix® is available as the tablet for oral use, containing 4.5 mg and 18 mg of Pitolisant hydrochloride. The initial dose of 9 mg (two 4.5 mg, tablets) per day, and it should be used at the lowest effective dose, depending on individual patient response and tolerance, according to an up-titration scheme, without exceeding the dose of 36 mg/day. Pitolisant was the first clinically used H3 receptor inverse agonist.