Positives

• Donepezil is among the medications cited in current Long COVID brain-fog reviews as worth a trial in selected patients, alongside methylphenidate, modafinil, luteolin, nicotinamide riboside, and vitamin C Psychiatric Times.
  
  

Negatives

• Patients with post-COVID memory impairment given donepezil 5 mg for 12 weeks commonly report no meaningful change in their memory complaints, with only narrow improvements showing up on a few subtests PubMed.
• Off-label cholinesterase inhibitor use for mild cognitive impairment can pose cardiac risks in some patients, and donepezil is widely associated with nausea, diarrhea, and decreased appetite that often forces discontinuation UCLA Health.

Hurdles & Side Effects

• Off-label prescribing for Long COVID is uncommon outside academic clinics, so most patients seeking it need to find a neurologist willing to write the trial and document baseline cognitive testing Yale School of Medicine.