Expansion
Many drugs each contribute a little, and the total predicts harm
Expansion
The peripheral toxidrome, remembered as: “blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bone, and the bowel and bladder lose their tone.”
- Blind: blurred vision, dilated pupils
- Mad: confusion, agitation, hallucinations
- Red: flushed skin
- Hot: hyperthermia
- Dry: dry mouth and skin, no sweating, which distinguishes it from sympathomimetic toxicity
- Bowel and bladder: urinary retention, constipation, ileus
Drugs contributing, often unrecognised because each seems minor:
- Tricyclic antidepressants: amitriptyline
- Bladder antimuscarinics: oxybutynin, tolterodine, solifenacin
- Antihistamines: chlorphenamine, promethazine
- Antipsychotics: olanzapine, quetiapine, chlorpromazine
- Antiemetics: cyclizine, prochlorperazine, hyoscine
- Antispasmodics, some antiparkinsonian agents, and codeine
“It is the total that matters, not any single drug.” Scoring tools such as the ACB scale give each drug a score, and a total of 3 or more is associated with cognitive impairment, falls, and increased mortality in older people.
Deprescribing is the intervention: it is among the most reversible causes of confusion and falls, and it directly opposes cholinesterase inhibitors in dementia.