A reader contacted me because she was concerned about cognitive issues after she started Dramamine. It is a microbiome modifier.

IMHO Brain Fog should be a condition that should result in de-prescribing or stopping any of the following.

From healthline, we have the following list

Over the counter anticholinergics

• diphenhydramine (Benadryl, Tylenol PM, Advil PM, Unisom SleepGels, Dimedrol, Daedalon, and Nytol.)
• brompheniramine (Dimetappm, Dimetapp, Bromfenex, Dimetane, and Lodrane)
• dimenhydrinate (Dramamine or Gravol)
  Dimenhydrinate is marketed under many brand names: in the U.S., Mexico, Turkey and Thailand as Dramamine; in Serbia as Dimigal; in Ukraine as Driminate; in Canada, Costa Rica, and India as Gravol; in Iceland as Gravamin; in Russia and Croatia as Dramina; in South Africa and Germany as Vomex; in Australia and Austria as Vertirosan; in Brazil as Dramin; in Colombia as Mareol; in Ecuador as Anautin; in Hungary as Daedalon; in Indonesia as Antimo; in Italy as Xamamina or Valontan; in Peru as Gravicoll; in Poland and Slovakia as Aviomarin;^[18] in Portugal as Viabom, Vomidrine, and Enjomin; in Spain as Biodramina; in Israel as Travamin; and in Pakistan as Gravinate.^[19]
• doxylamine (Unisom SleepTabs, Diclectin, Diclegis)

Prescription anticholinergics

• atropine (Atropen)
• belladonna alkaloids
• benztropine mesylate (Cogentin)
• clidinium
• cyclopentolate (Cyclogyl)
• darifenacin (Enablex)
• dicylomine
• fesoterodine (Toviaz)
• flavoxate (Urispas)
• glycopyrrolate
• homatropine hydrobromide
• hyoscyamine (Levsinex)
• ipratropium (Atrovent)
• orphenadrine
• oxybutynin (Ditropan XL)
• propantheline (Pro-banthine)
• scopolamine
• methscopolamine
• solifenacin (VESIcare)
• tiotropium (Spiriva)
• tolterodine (Detrol)
• trihexphenidyl
• trospium

For more, from Drugs.com: Anticholinergic Drugs to Avoid in the Elderly

Some Literature

The amount of literature is HUGE, I will just cite back to September 2023….

• Association of systemic anticholinergic medication use and accelerated decrease in lung function in older adults [2024]
• Oxybutynin-Associated Cognitive Impairment: Evidence and Implications for Overactive Bladder Treatment [2024] “a first-generation anticholinergic, accounts for more than half of all OAB medication prescriptions” “associated with adverse cognitive outcomes”
• Increased anticholinergic medication use in middle-aged and older autistic adults and its associations with self-reported memory difficulties and cognitive decline [2023]
  “Among older adults, anticholinergic medications are associated with cognitive impairment and risk for cognitive disorders, including Alzheimer’s disease.”
• Clinical pharmacist-led assessment and management of anticholinergic burden and fall risk in geriatric patients [2023] “Risk of falls increased 2.50 times in patients with high anticholinergic burden”
• Anticholinergic deprescribing interventions for reducing risk of cognitive decline or dementia in older adults with and without prior cognitive impairment [2023] “There is insufficient evidence to reach any conclusions on the effects of anticholinergic burden reduction interventions on cognitive outcomes in older adults with or without prior cognitive impairment. ” — that is, stopping may not reverse it effects.
• Drugs with a negative impact on cognitive functions (Part 2):… [2023]
• Association of anticholinergic drug exposure with the risk of dementia among older adults in Japan: The LIFE Study [2023] “Several types of anticholinergic drugs used by older adults in Japan are associated with an increased risk of dementia. “
• Low-Income Older Adults’ Vulnerability to Anticholinergic Medication-Associated Frailty [2023]
• Association between recently raised anticholinergic burden and risk of acute cardiovascular events: nationwide case-case-time-control study [2023] “An association was found between recently raised anticholinergic burden and increased risk of acute cardiovascular events. Furthermore, a greater increase in anticholinergic burden was associated with a higher risk of acute cardiovascular events.”
  

Which Bacteria may be causing the Cognitive Declines?

Many of the drugs above are in the Microbiome Prescription database. Many of them impacts the same bacteria [ DECREASING] — implying that the cognitive loss may be connected with microbiome alteration.

The obvious way to improve recovery appears to be the following probiotics:

• Escherichia coli (Mutaflor, Symbioflor 2)
• Akkermansia muciniphila (Pendulum)
• Bifidobacterium adolescentis
• Bifidobacterium longum
• Lactobacillus casei group

In Common Across Drugs	Bacteria
19	Enterobacteriaceae
18	Escherichia
18	Escherichia coli
18	Kluyvera
18	Streptococcaceae
18	Streptococcus
18	Streptococcus parasanguinis
17	Akkermansia
17	Akkermansia muciniphila
17	Bacteroidaceae
17	Bacteroides
17	Bacteroides caccae
17	Bacteroides fragilis
17	Bacteroides ovatus
17	Bacteroides thetaiotaomicron
17	Bacteroides uniformis
17	Bacteroides xylanisolvens
17	Bifidobacteriaceae
17	Bifidobacterium
17	Bifidobacterium adolescentis
17	Bifidobacterium longum
17	Bilophila
17	Bilophila wadsworthia
17	Blautia
17	Clostridiaceae
17	Clostridioides
17	Clostridioides difficile
17	Clostridium
17	Collinsella
17	Collinsella aerofaciens
17	Coprococcus
17	Coriobacteriaceae
17	Desulfovibrionaceae
17	Dorea
17	Dorea formicigenerans
17	Eggerthella
17	Eggerthella lenta
17	Eubacteriaceae
17	Eubacterium
17	Fusobacteriaceae
17	Fusobacterium
17	Fusobacterium nucleatum
17	Lachnospiraceae
17	Lacticaseibacillus paracasei
17	Lactobacillus
17	Lactobacillus casei group
17	Odoribacter
17	Odoribacter splanchnicus
17	Parabacteroides
17	Parabacteroides distasonis
17	Parabacteroides merdae
17	Peptoclostridium
17	Peptostreptococcaceae
17	Phocaeicola vulgatus
17	Porphyromonadaceae
17	Prevotella
17	Prevotellaceae
17	Roseburia
17	Roseburia hominis
17	Roseburia intestinalis
17	Ruminococcaceae
17	Ruminococcus
17	Streptococcus salivarius
17	Veillonella
17	Veillonella parvula
17	Veillonellaceae
17	Verrucomicrobiaceae

Post Script:

A comment on this post wrote “I take Huperzine A and always wonder if that helps me out a little. (I can’t take any of those strong central anticholinergics anyway though!)“.

Huperzine A, the active ingredient derived from the traditional Chinese herb, is an efficacious, selective, and reversible acetylcholinesterase inhibitor (AChEI) 

So, does it impact cognitive issues in these groups? There is no clear evidence (mixed results in most reviews)

• Effect of Huperzine A on Cognitive Function and Perception of Effort during Exercise: A Randomized Double-Blind Crossover Trial [2021] “Huperzine A does not enhance cognitive function during exercise despite it being marketed as a cognitive enhancer”