[Pharmacodynamics and pharmacokinetics of memantine]

The adamantane derivative memantine (1-amino-3,5-dimethylaminoadamantane, D-145, Akatinol) is clinically used as well in the therapy of neurogenic motor diseases (e.g. spasticity) as in the treatment of cerebral disorders like coma, cerebrovascular and geronto-psychiatric disturbances. The aim of the paper is to summarize experimental evidences that may help to explain the clinical observations. Biochemical, pharmacological, and electrophysiological studies show that memantine interferes with the metabolism of the transmitters dopamine, noradrenaline (norepinephrine), and serotonin and modulates synaptic transMission. In order to explain the antispastic activity of memantine, a spinal action must be assumed in addition to the supraspinal effect on transmitter systems. Since memantine reduces the membrane resistance as well as the membrane conductance of sodium, potassium, and chloride ions, it is very likely that memantine Is directly involved in the generation of action potentials.