Symptoms of anticholinergic syndrome
| Description | Mechanism |
|---|---|
| Red as a beet | Compensating for the loss of sweat leads to excessive vasodilation of the skin to maximise heat loss |
| Dry as a bone | Muscarinic action causes sweat glands to activate, therefore, anticholinergics cause anhidrosis (absence of sweat) |
| Hot as a hare | The removal of the normal thermal haemostasis mechanisms often results in high fever |
| Blind as a bat | Pupillary constriction and accommodation rely on muscarinic receptors, therefore, anticholinergics cause pupillary dilation and blurry vision |
| Mad as a hatter | The loss of central nervous system muscarinic receptor action can lead to a range of symptoms from anxiety, delirium, visual hallucinations through to seizures and coma |
| Full as a drum | Both the detrusor muscle and urinary sphincter are under muscarinic control and therefore anticholinergics will lead to a decreased signal to urinate and an increase in urinary retention |
| Non-mnemonic | Loss of muscarinic receptors means there is unopposed sympathetic action on the heart, giving tachycardia. There is also slowing (or complete absence) of bowel sounds |