Too much glutamate is damaging or toxic to the nerve cell. NMDA antagonists work very differently from cholinesterase inhibitors. The dosage is based on how well a patient tolerates the drug. The recommended effective final dosage of Memantine is 20 mg/day after the patient has successfully tolerated lower doses. Memantine is the first drug for people in the later stages of the disease. A number of other treatments, including Vitamin E, estrogen and anti-inflammatory drugs have shown some promising associations, but are not yet proven for routine use. Plants like Ginkgo biloba are available in many countries,yet underinvest-igated. Ginkgo extract seems to improve cerebral blood flow, but consistent benefits with it have not been demonstrated.