Can Namenda (memantine) cause somnolence?

Memantine (Namenda) Can Cause Somnolence

Yes, memantine can cause somnolence as a side effect, as documented in the FDA drug labeling information. 1

Evidence from Drug Labeling

• The FDA labeling for memantine specifically lists somnolence as a potential adverse effect that can occur with use of the medication 1
• In cases of memantine overdose, somnolence is among the reported symptoms, along with other neurological effects such as confusion, dizziness, and unsteady gait 1

Incidence and Risk

• Research studies have identified somnolence as one of the adverse effects associated with memantine treatment for Alzheimer's disease 2, 3
• A 2013 meta-analysis found that memantine treatment significantly increased the risk for somnolence compared to placebo in patients with Alzheimer's disease 2
• A 2015 meta-analysis of randomized controlled trials confirmed that memantine therapy increased the risk for somnolence in patients 3

Effect on Sleep Architecture

• Interestingly, a 2016 study examining memantine's effects on sleep architecture found that it actually improved total sleep time and sleep efficiency while decreasing nocturnal awakening in Alzheimer's patients 4
• This suggests that while somnolence is a reported side effect, memantine may have complex effects on sleep patterns that could be beneficial for some patients 4

Clinical Implications

• When prescribing memantine, healthcare providers should monitor patients for signs of somnolence, especially during the initial titration period 1
• Patients should be counseled about the potential for somnolence and advised to use caution when performing activities requiring alertness until they know how the medication affects them 1, 2
• The risk of somnolence should be weighed against the potential benefits of memantine in improving cognitive function and clinician's global impression in patients with Alzheimer's disease 2, 3

Other Common Side Effects

• Besides somnolence, other commonly reported adverse effects of memantine include dizziness, headache, confusion, and constipation 1
• In some cases, memantine has been associated with weight gain, hypertension, nervous system disorders, and increased risk of falling 2

Monitoring Recommendations

• Regular follow-up is recommended to assess both therapeutic response and potential adverse effects including somnolence 1
• If significant somnolence occurs, dosage adjustment or discontinuation may be necessary, especially in patients at high risk for falls or those who operate machinery 1, 2