| Drug | Approved Indication | Suggested Dosage | Side Effects | Additional Notes/Caution |
|---|---|---|---|---|
| Cholinesterase inhibitors | ||||
| Donepezil (Aricept) | Mild to moderate AD | Once daily, beginning with 5 mg/day, which can be increased to 10 mg/day (maximum dosage) after 4 weeks | AEs are mild and include nausea, vomiting, and diarrhea | Gastrointestinal-related AEs can be reduced if medication taken with food Some patients exhibit an initial increase in agitation, which subsides after first few weeks of therapy |
| Severe AD | ||||
| Rivastigmine (Exelon) | Mild to moderate AD | Oral: Twice daily, beginning with 1.5 mg Transdermal patch: Once daily, 4.6 or 9.5 mg The target dose is 9.5 mg/24 hr per patch (a 10 cm2 patch) and requires a simple one-step dose titration to the therapeutic dose There is a higher-dose patch (20 cm2) available, delivering 17.4 mg/24 hr; however, it is currently an unapproved treatment in the United States. Lack of approval was based on it having similar efficacy to the 10 cm2 patch, but with a tolerability profile comparable to that of the capsule formulation | AEs include nausea, vomiting, diarrhea, weight loss, headaches, abdominal pain, fatigue, anxiety, and agitation Gastrointestinal-related AEs are less prominent with the patch: the 9.5 mg/24 hr patch provides efficacy similar to that of the highest dose of capsules, with 3 times fewer reports of nausea and vomiting | Higher dosages are more efficacious than lower dosages No laboratory monitoring is required |
| Galantamine (Razadyne) | Mild to moderate AD | Twice daily, beginning with 4 mg After 4 weeks, dosage is increased to 8 mg twice daily An increase to 12 mg twice daily can be considered on an individual basis after assessment of clinical benefit and tolerability Also available in an extended-release formulation that can be taken once daily | Most common side effects are nausea, vomiting, and diarrhea | Gastrointestinal-related AEs can be minimized by titrating the dosage gradually and taking the medication with meals |
| NMDA antagonist | ||||
| Memantine (Namenda) | Moderate to severe AD | Twice daily, beginning with 5 mg, increasing the dose to 10 mg twice daily over 3 weeks | AEs include fatigue, pain, hypertension, headache, constipation, vomiting, back pain, somnolence, dizziness | Moderate to severe AD may respond better with memantine/donepezil combination versus donepezil alone |
AE, adverse event; NMDA, N-methyl D-aspartate.