Can Namenda (memantine) cause orthostatic hypotension?

Namenda (Memantine) and Orthostatic Hypotension

Namenda (memantine) is not strongly associated with orthostatic hypotension, and other medications should be considered as more likely culprits when evaluating a patient with orthostatic symptoms. 1

Medication Classes Associated with Orthostatic Hypotension

• Alpha-1 blockers (doxazosin, prazosin, terazosin) are strongly associated with orthostatic hypotension, especially in older adults 1
• Centrally-acting antihypertensives (clonidine, methyldopa, guanfacine) commonly cause orthostatic hypotension 1
• Diuretics, particularly when causing volume depletion, are frequent contributors to orthostatic symptoms 1
• Vasodilators such as hydralazine and minoxidil can significantly lower blood pressure upon standing 1

Memantine and Cardiovascular Effects

• In clinical trials of memantine for Alzheimer's disease and vascular dementia, the adverse event profile was generally comparable to placebo 2
• While dizziness was reported at a higher rate with memantine compared to placebo, this was not specifically attributed to orthostatic hypotension in the literature 2
• Unlike many psychotropic and neurologic medications, memantine has not been identified as a significant cause of orthostatic hypotension in major guidelines 1

Management of Drug-Induced Orthostatic Hypotension

When orthostatic hypotension is suspected to be medication-related:

1. Identify and discontinue medications that exacerbate postural symptoms as first-line treatment 1
2. Consider switching to medications with minimal impact on orthostatic blood pressure rather than simply reducing doses 1
3. For patients requiring antihypertensive therapy who have orthostatic hypotension:
   • Long-acting dihydropyridine calcium channel blockers should be considered first-line 1
   • RAS inhibitors (ACE inhibitors or ARBs) are also recommended as first-line agents with minimal orthostatic effects 1
   • Beta-blockers should be avoided unless there are compelling indications 1

Non-Pharmacological Management

• Gradual staged movements with postural change to minimize blood pressure drops 1
• Physical counter-maneuvers such as leg crossing and muscle tensing 1
• Increased fluid and salt intake to maintain adequate blood volume 1
• Abdominal binders can be particularly effective for managing orthostatic symptoms 3

Clinical Pearls

• When evaluating orthostatic hypotension in patients taking memantine, look for other more likely causes including other medications, volume depletion, or neurogenic causes 1
• Drug-induced autonomic failure is probably the most frequent cause of orthostatic hypotension, with diuretics and vasodilators being the most important agents in this setting 4
• Before starting or intensifying any medication in patients with suspected orthostatic hypotension, test for orthostatic changes by measuring blood pressure after 5 minutes of sitting/lying and then 1 and/or 3 minutes after standing 1

In conclusion, while memantine has been associated with dizziness in some patients, it is not prominently identified as a cause of orthostatic hypotension in clinical guidelines, and other medications should be considered as more likely culprits when evaluating orthostatic symptoms.