++

An anticholinergic is a substance that antagonizes the action of the neurotransmitter acetylcholine. A large number of pharmaceuticals and substances found in plants possess anticholinergic activity (Table 196-1). Atropine (D,L-hyoscyamine), hyoscyamine, and scopolamine (L-hyoscine) are natural alkaloids that represent prototypical anticholinergic compounds. An important principle of anticholinergic toxicity is that many substances possess anticholinergic activity, either as a direct therapeutic effect or an adverse effect, in addition to their primary or predominant pharmacologic effect.

++
Table Graphic Jump Location
Table 196-1 Major Groups of Substances with Anticholinergic Activity 
++

Antihistamines (particularly diphenhydramine) are the most common overdose that produces anticholinergic toxicity. Young children may accidentally ingest a few pills, such as orphenadrine, that can cause toxicity from its anticholinergic properties.1 Other examples of pediatric exposures causing anticholinergic toxicity include hyoscyamine-containing agents to treat colic, the topical use of diphenhydramine-containing salves, and therapeutic application of a transdermal hyoscine patch.2–5 Conversely, in the elderly, therapeutic doses of one or multiple medications with anticholinergic properties may produce anticholinergic toxicity.6,7 In addition, ophthalmologic instillation of anticholinergic mydriatic agents can cause toxicity, especially in the elderly.8

++

Atropine is the antidote for a cholinergic syndrome produced from a nerve agent or an organophosphate insecticide.9 Use of high-dose atropine by someone who is not suffering from the effects of cholinesterase poisoning may result in anticholinergic toxicity. This occurred in Israel during the first Gulf War in 1991 when frightened civilians dosed themselves with atropine fearing an incoming Scud missile chemical weapon attack.

++

Plant poisonings may result in an anticholinergic toxidrome. In Taiwan, the anticholinergic toxidrome is most commonly associated with single-plant exposures.10 Belladonna alkaloid-containing plants have potent anticholinergic effects producing toxicity 1 to 4 hours postingestion or sooner if smoked. Alkaloid plants are abused for their hallucinogenic effects.11,12 Group anticholinergic plant ingestions are common in adolescents seeking these psychoactive hallucinogenic effects.13,14 Inadvertent poisoning from the ingestion of belladonna-contaminated ...

Want access to your institution's subscription?

Sign in to your MyAccess Account while you are actively authenticated on this website via your institution (you will be able to tell by looking in the top right corner of any page – if you see your institution’s name, you are authenticated). You will then be able to access your institute’s content/subscription for 90 days from any location, after which you must repeat this process for continued access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess account, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessMedicine Full Site: One-Year Subscription

Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessMedicine

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.