Background: Acetylcholinesterase inhibitors (AChEIs) and the N-methyl d-aspartate-antagonist memantine are indicated for the symptomatic treatment of Alzheimer’s disease (AD). Objectives: Our aims were to describe the baseline characteristics of patients with AD according to prescription of these treatments after the diagnostic work-up to describe long-term trends in the use of these medications and to identify baseline characteristics associated with the frequency of use of each treatment. Methods: This was a cohort study with a sample of 2992 patients with AD recorded in the Registry of Dementias of Girona (ReDeGi) between 2007 and 2014. Consumption of AChEIs and memantine was assessed using the Pharmacy Unit database from the Public Catalan Healthcare Service. We used generalized estimating equation analyses to identify the baseline characteristics associated with the consumption of AChEIs and memantine over time. Results: Most of the patients (70.4%; 95% confidence interval [CI] 68.7–72.0) were prescribed antidementia medication at the time of diagnosis. Of these, 75.0% (95% CI 73.1–76.8) were prescribed AChEIs, 14.7% (95% CI 13.2–16.3) were prescribed an AChEI plus memantine, and 10.3% (95% CI 9.0–11.6) were prescribed memantine. Advanced age reduced the likelihood of AChEI consumption. Mild dementia severity increased the use of AChEIs, and moderate–advanced dementia increased the likelihood of memantine consumption. After diagnosis, the likelihood of AChEI consumption decreased from the first year until the fifth, whereas the likelihood of memantine consumption, either alone or in combination with AChEIs, increased. Conclusions: Antidementia drug use in this study showed the initial use of AChEIs alone with later use of AChEIs in combination with memantine and memantine alone in older patients with severe AD. Our findings are in agreement with current clinical practice guidelines for the pharmacological treatment of AD.