Trichlorfon (Metrifonate), the organophosphorous cholinesterase inhibitor, O,O-dimethylhydroxy-2,2,2-trichlorethyl-phosphonate, has been used sporadically in the treatment of human schistosomiasis for a decade. It has selective and variable schistosomicidal activity against S. haematobium that results from its partial metabolism to a highly active anti-cholinesterase, dichlorvos. Schistosomal cholinesterase is more susceptible to this metabolite than that of the human host, but transient reductions in both plasma and erythrocyte cholinesterase activity are demonstrable at therapeutic dosage. However, despite early concerns about its potential toxicity, metrifonate is well tolerated and has been used effectively and extensively in large-scale control programmes. Its potential to enhance central nervous system cholinergic neurotransmission led to clinical trials for the treatment of people with Alzheimer's disease (AD).

Trichlorfon (Metrifonate), the organophosphorous cholinesterase inhibitor, O,O-dimethylhydroxy-2,2,2-trichlorethyl-phosphonate, has been used sporadically in the treatment of human schistosomiasis for a decade. It has selective and variable schistosomicidal activity against S. haematobium that results from its partial metabolism to a highly active anti-cholinesterase, dichlorvos. Schistosomal cholinesterase is more susceptible to this metabolite than that of the human host, but transient reductions in both plasma and erythrocyte cholinesterase activity are demonstrable at therapeutic dosage. However, despite early concerns about its potential toxicity, metrifonate is well tolerated and has been used effectively and extensively in large-scale control programmes. Its potential to enhance central nervous system cholinergic neurotransmission led to clinical trials for the treatment of people with Alzheimer's disease (AD).

Velnacrine (9-amino-1,2,3,4-tetrahydroacridin-1-ol) is an inhibitor of acetylcholinesterase. It was studied for the treatment of Alzheimer's disease however development was discontinued. There has been no research into the use of velnacrine as a cognitive enhancer in the treatment of Alzheimer's disease since 1994. The FDA peripheral and CNS drug advisory board voted unanimously against recommending approval. This review shows the toxic nature of velnacrine, and provides no evidence of efficacy.

Velnacrine (9-amino-1,2,3,4-tetrahydroacridin-1-ol) is an inhibitor of acetylcholinesterase. It was studied for the treatment of Alzheimer's disease however development was discontinued. There has been no research into the use of velnacrine as a cognitive enhancer in the treatment of Alzheimer's disease since 1994. The FDA peripheral and CNS drug advisory board voted unanimously against recommending approval. This review shows the toxic nature of velnacrine, and provides no evidence of efficacy.

Velnacrine (9-amino-1,2,3,4-tetrahydroacridin-1-ol) is an inhibitor of acetylcholinesterase. It was studied for the treatment of Alzheimer's disease however development was discontinued. There has been no research into the use of velnacrine as a cognitive enhancer in the treatment of Alzheimer's disease since 1994. The FDA peripheral and CNS drug advisory board voted unanimously against recommending approval. This review shows the toxic nature of velnacrine, and provides no evidence of efficacy.

Velnacrine (9-amino-1,2,3,4-tetrahydroacridin-1-ol) is an inhibitor of acetylcholinesterase. It was studied for the treatment of Alzheimer's disease however development was discontinued. There has been no research into the use of velnacrine as a cognitive enhancer in the treatment of Alzheimer's disease since 1994. The FDA peripheral and CNS drug advisory board voted unanimously against recommending approval. This review shows the toxic nature of velnacrine, and provides no evidence of efficacy.

Velnacrine (9-amino-1,2,3,4-tetrahydroacridin-1-ol) is an inhibitor of acetylcholinesterase. It was studied for the treatment of Alzheimer's disease however development was discontinued. There has been no research into the use of velnacrine as a cognitive enhancer in the treatment of Alzheimer's disease since 1994. The FDA peripheral and CNS drug advisory board voted unanimously against recommending approval. This review shows the toxic nature of velnacrine, and provides no evidence of efficacy.

Nicergoline is a semisynthetic ergoline derivative that has been used as a cerebral vasodilator and in peripheral vascular disease. Nicergoline seems to have an action: (i) as an alpha1-adrenoceptor antagonist, it induces vasodilation and increases arterial blood flow; (ii) it enhances cholinergic and catecholaminergic neurotransmitter function; (iii) it inhibits platelet aggregation; (iv) it promotes metabolic activity, resulting in increased utilization of oxygen and glucose; and (v) it has neurotrophic and antioxidant properties. Nicergoline has been suggested to ameliorate cognitive deficits in cerebrovascular disease.

Zanapezil (TAK-147) is a selective reversible acetylcholine (ACh) esterase inhibitor that was designed as a drug for Alzheimer's disease (AD) treatment. The development of the drug was discontinued due to a lack of a dose-dependent effect in the trials.

Pyritinol is a semi natural analogue of water soluble vitamin B6. Pyritinol was synthetized way back in 1961 by Merck Laboratories. After years of research, it entered the market in the 1970s, where it was used for clinical applications – including treating stroke patients and those with Alzheimer’s. Since the 1990s, it has been sold as a nootropic dietary supplement in the United States and many other parts of the world. Pyritinol, unlike many other nootropics, has been approved for use as a medical treatment in countries around the world. Doctors in many European countries use Pyritinol to treat patients with chronic degenerative brain disorders – like dementia. Countries where Pyritinol is an approved treatment include Austria, Germany, France, Greece, Italy, and Portugal. France has approved the use of Pyritinol – but only as a treatment for rheumatoid arthritis. Pyritinol is not currently licensed for use in the United Kingdom, but in most other countries, it’s available online or through drug stores as an over the counter substance. Pyritinol is marketed under the brand names Encephabol, Encefabol and Cerbon 6. One of the known mechanisms of action of Pyritinol involves increasing choline uptake into your neurons and thereby increasing acetylcholine levels. Pyritinol is also a great effective precursor to dopamine, which is one of the neurotransmitter mood-boosters in the brain. Pyritinol has better conversion into the neurochemical. This drug increases dopamine, which can keep the brain from anxiety because a lower dopamine level is connected to mood disorders and depression.