A drug combination therapy useful in the treatment of dementia associated with disorders of the central nervous system, e.g. to delay the onset or progression of Alzheimers disease, cerebrovascular disease or Downs syndrome, comprises a combination of a 1-aminocyclohexane derivative such as memantine or neramexane and an acetylcholinesterase inhibitor such as galantamine, tacrine, donepezil or rivastigmine.