Cholinesterase inhibitors are used for the symptomatic treatment of patients with Alzheimer's disease. This population often has numerous comorbidities and receives treatment with multiple medications. The astute clinician should remain mindful of possible drug interactions, both pharmacokinetic and pharmacodynamic, that may occur with concomitant treatment. Although pharmacokinetic interactions have been reported, pharmacodynamic interactions play a far greater role in the significance of drug interactions, with anticholinergic medications being most concerning. Commonly prescribed medications, such as antihistamines and tricyclic antidepressants, often have anticholinergic properties that alone or in combination with one another can antagonise the effects of cholinesterase inhibitors. Other medication classes such as antipsychotics and cholinergic agents may also result in pharmacodynamic interactions. However, for the most part, cholinesterase inhibitors can be used safely in combination with other medications.