How long will it take for memantine (generic name) to suppress my appetite again after resuming the 20mg dose?

Memantine and Appetite Suppression: Timeline for Effect Resumption

When you resume memantine 20 mg after briefly dropping to 15 mg, appetite suppression should return within 1-3 days, as memantine reaches peak plasma levels 1-3 hours after ingestion and achieves steady-state concentrations within approximately 3-7 days.

Pharmacokinetic Considerations

The rapid return of appetite suppression you may experience is consistent with memantine's pharmacological profile:

• Memantine reaches peak plasma concentrations 3-7 hours after oral administration 1
• Steady-state levels are typically achieved within 3-7 days of consistent dosing 1
• The drug has a relatively long elimination half-life (60-80 hours), meaning some drug remains in your system even after dose reduction 1

Why You Felt Hungry at 15 mg

Your experience of increased hunger when dropping to 15 mg is plausible:

• Appetite suppression is a recognized effect of memantine, though it's more commonly reported as an adverse effect (decreased appetite/anorexia) rather than a therapeutic benefit 2, 3
• The dose-response relationship suggests that the 5 mg difference between 15 mg and 20 mg was sufficient to reduce the appetite-suppressing effect below your threshold 4, 5
• Your hunger likely emerged within 24-48 hours of dose reduction as plasma levels decreased 1

Expected Timeline for Appetite Suppression Return

When you resumed 20 mg:

• Day 1: Peak levels return within hours, you may notice some appetite suppression the same day or next day 1
• Days 2-3: Plasma concentrations approach previous steady-state levels, appetite suppression should become more consistent 1
• Days 3-7: Full steady-state is re-established, appetite suppression should return to baseline effect 1

Important Clinical Caveats

Memantine is not FDA-approved for appetite suppression or weight management 2, 3. The primary indications are:

• Moderate to severe Alzheimer's disease 2, 5
• Parkinson's disease dementia, dementia with Lewy bodies, or vascular dementia 2

Common adverse effects of memantine include nausea (4-18%), diarrhea (4-18%), and agitation (4-18%) 3. While decreased appetite can occur, using memantine specifically for appetite suppression is off-label and not supported by guidelines 2, 3.

If you are taking memantine for an approved indication (such as dementia), the appetite suppression is a side effect that happens to be beneficial for you. However, if appetite suppression is your primary goal, FDA-approved weight management medications would be more appropriate 1.

Monitoring Recommendations

• Track your appetite daily for the first week after resuming 20 mg to document when suppression returns 2
• Be aware that tolerance to side effects (including appetite changes) can develop over time 3, 5
• Ensure you're taking memantine as prescribed for its intended indication, not solely for appetite control 2