Safety and tolerability of rivastigmine capsule with memantine in patients with probable Alzheimer's disease: a 26-week, open-label, prospective trial (Study ENA713B US32)

Abstract

Objective: Rivastigmine, a dual cholinesterase inhibitor (ChEI), is widely approved for the symptomatic treatment of both mild-to-moderate Alzheimer's disease (AD) and Parkinson's disease dementia. Orally administered ChEIs may be associated with gastrointestinal (GI) side effects and add-on therapy with memantine, an N-methyl-d-aspartate receptor antagonist, approved for moderate-to-severe AD, may ameliorate such side effects. This was a 26-week, prospective, multicenter, single-arm, open-label pilot study to assess the safety and tolerability of rivastigmine capsules plus memantine in patients with moderate AD.

Methods: The primary objective was to assess the safety and tolerability of rivastigmine capsules 6-12 mg/day plus memantine (5-20 mg/day) as measured by the incidences of vomiting and nausea compared with those reported in the rivastigmine United States Prescribing Information (US PI). A total of 117 patients were enrolled with 116 receiving at least one dose of study medication.

Results: The incidences of nausea and vomiting (30% and 13%, respectively) observed in patients who received 6-12 mg/day rivastigmine plus memantine were lower than those stated in the US PI for rivastigmine monotherapy 6-12 mg/day (47% and 31%, respectively). The most common adverse events were nausea, vomiting, and dizziness.

Conclusion: Results from this study suggest the combination of rivastigmine capsule and memantine in patients with moderate AD is safe and tolerable. A greater reduction in the GI tolerability of rivastigmine has been established with rivastigmine transdermal patch.