Mechanism of action of amantadine?

How does amantadine work?

Amantadine’s best-known mechanism is that it blocks the viral M2 ion channel found in influenza A. By inhibiting this proton channel, it prevents acidification inside the virus (endosomal/uncoating step), which the virus needs to release its genetic material and start replication.

Does amantadine have any other mechanisms besides the M2 channel?

Yes. Amantadine also has effects on the nervous system that are relevant to its use in neurologic conditions. It increases dopaminergic activity and also affects glutamatergic signaling by antagonizing NMDA (N-methyl-D-aspartate) receptors. These actions help explain its clinical benefits in disorders involving dopamine/neuronal overactivity and excitatory transmission.

How do those actions relate to its clinical uses?

For infectious disease use targeting influenza A, the key effect is M2 channel blockade. For neurologic uses (for example, movement disorders), the dopaminergic and NMDA-antagonist effects are the main contributors to symptom improvement rather than antiviral channel inhibition.

What does amantadine not do?

Amantadine does not inhibit influenza B, because influenza B does not have the M2 ion channel target present in influenza A.