Table 1.
The main current therapies and their mechanisms, effects, and limitations for neurodegenerative diseases.
| Drugs | Mechanisms | Main effects | Main limitations | Diseases |
|---|---|---|---|---|
| Donepezil, Ralantamine, Rivastigmine | Inhibiting acetylcholinesterase | Increasing levels of synaptic acetylcholine | Increasing cognitive impairment; low CNS selectivity; gastrointestinal toxicity (nausea, vomiting, and diarrhea) | AD [18–24] |
| Memantine | Antagonizing N-methyl-D-aspartate-receptor (NMDAR) | Blocking glutamate from accessing NMDA receptors | Inability to slow down the progression of the disease | |
| Aducanumab | Human, immunoglobulin gamma 1 (IgG1) monoclonal antibody | Reducing aggregated soluble and insoluble forms of Aβ | High cost and failure to show definite effect in clinical trials | |
| Levodopa+Carbidopa | Inhibiting DA precursor and DOPA decarboxylase | Increasing DA levels in SNc | Wearing and movement disorders; dizziness and gastrointestinal upset | PD [25–28] |
| Pramipexole and Apomorphine | Agitating DA | Activating DA receptors | Less effective than levodopa; worsen dyskinesia | |
| Selegiline, Rasagiline, and Safinamide | Inhibiting monoamine oxidase B (MAO-B) | Preventing DA metabolism | Mild efficacy in monotherapy | |
| Gocovri (Amantadine) | Antivirus | Reducing levodopa-induced dyskinesia | Several side effects including psychosis, edema, constipation, and livedo reticularis | |
| Trihexyphenidyl | Antagonizing muscarinic acetylcholine receptor | Reducing tremor | Serious side effects including memory impairment, confusion, and hallucinations | |
| Levodopa+Carbidopa+Istradefylline | Inhibiting DA precursor, DOPA decarboxylase, and antagonizing A2A receptor | Reducing the “off” episodes | Higher incidence of treatment-emergent adverse events (TEAEs) and dyskinesia | |
| Levodopa+Carbidopa+Opicapone | Inhibiting DA precursor, DOPA decarboxylase, and catechol-o-methyl transferase (COMT) | Reducing the “off” episodes | Higher incidence of TEAEs and worsen dyskinesia than istradefylline | |
| Tetrabenazine (TBZ; Xenazine™) and deutetrabenazine (AUSTEDO™) | Inhibiting vesicular monoamine transporter type 2 (VMAT2) | Treating chorea associated with HD and tardive dyskinesia | Inability to slow down the progression of the disease | HD [29] |
| Riluzole | Blocking the presynaptic release of glutamate | Inhibiting the excitotoxicity | High cost and modest efficacy | ALS [30–33] |
| Edaravone (RADICAVATM) | Antioxidant | Protecting neuronal cells from oxidative stress, ameliorating motor dysfunction | Limited patient population |