Twelve patients with "brain fog" including difficulties in executive functions were treated with guanfacine (1mg, PO bedtime for the first month, increased to 2mg after 1 month, if well-tolerated) and 600 mg NAC daily. Guanfacine+NAC improved cognitive abilities in eight of the twelve patients; four patients discontinued therapy, two for unspecified reasons and two due to hypotension and/or dizziness, common side effects of guanfacine. Those who stayed on guanfacine+NAC reported improved working memory, concentration, and executive functions, including a resumption of normal workloads. One patient briefly stopped taking guanfacine due to a hypotensive episode and reported a return of cognitive deficits that abated with resumed guanfacine treatment.