My MIL recently started memantine to control delusional behaviour. She has completed the increasing dose regime with minimal side effects, and so far no episodes of delusions! So we are very pleased. However yesterday she complained of palpitations and dizziness which she thinks is because she started a new pack of tablets. But they are exactly the same as the last pack except the box us a different colour!! Anyone else know of this side effect? Or is it likely to be something else? Palpitations are not listed as a known effect on the drug leaflet. I told her to carry on taking it and ring the GP if she's no better.