Anticholinergic Toxicity

Dr. Cynthia M. Griffin D.O., NREMT‐P UW MedFlight Fellow @CMGrffn CMGriffin@Medicine.Wisc.edu

Trauma Symposium –The Dells, Wisconsin Anticholinergics = 3 Groups

• 1. Antimuscarinics Affect muscarinic ACh receptors • 2. Neuromuscular blocking Blocking nicotinic ACh receptors • 3. Ganglionic blockers Affecting ACh sympathetic & parasympathetic ganglia Anticholinergic Medications • Antihistamines: Diphenhydramine (Benadryl) • Atropine (Belladona), Scopolamine, Glycopyrrolate • TriCyclic Antidepressants ‐ Amytriptyline • Antispasmotics ‐ Dicyclomine • Amanita, Jimson Weed • Flexeril • Antiparkinsonian drugs – Benztropine, Cogentin • Ophthalmic Cyclopegics –mydriatics • Asthma Rx ‐ Ipratropium Classes: • Antihistamines function as inverse agonists on histamine receptors & inhibit muscarinic receptors

– H1 –CNS, heart, vasculature, airways, sensory nerves, GI smooth muscle, immune cells, and adrenal medulla

– H2 –gastric mucosa, heart, lung, uterus and immune cells Clinical Effects

• Central anticholinergic: – AMS, agitation, coma, psychosis, sz, fever • Peripheral Anticholinergic: – ilieus, dry skin & MM, fever, tachycardia, urinary retention, mydriasis, HTN, wide QRS complexes, dystonia • Na+ Channel Effects: – When sodium channels are blocked in the ♥ it manifests itself as a prolonged QRS interval on ECG • K+ Channel Effects: – When potassium channels are blocked in the ♥ it manifests itself as a prolonged QTc interval on ECG Anticholinergic s/s

• Pupil size –mydriasis–large / photophobia • Absence of bowel sounds, NV– intestinal motility slows • Temp ↑–concern for hyperthermia, inhibits sweat lands • HR↑ –tachycardia • Skin & MM – flushed & dry, decrease in capillary tone, glandular cells inhibited • Mental status – agitated delirium, visual hallucinations, seizure, coma • Urinary retention – contributes to agitation • Special –picking at air • Anticholinergic drugs are usually considered the least enjoyable by experienced recreational drug users, • Due to the lack of euphoria caused by them. • In terms of recreational use, these drugs are commonly referred to as deliriants. • Because most users do not enjoy the experience, they do not use it again, or do so very rarely. • The risk of addiction is low in the anticholinergic class. Hot as a Hare Blind as a Bat Dry as a Bone Red as a Beet Mad as a Hatter The Bowel & Bladder Lose their Tone And the Heart goes on Alone Mnemonic

Hot as a hare (hyperthermia) Blind as a bat (dilated pupils) Dry as a bone (dry skin) Red as a beet (vasodilation) Mad as a hatter (hallucinations/agitation) The bowel and bladder lose their tone and the heart goes on alone (ileus, urinary retention, tachycardia) PreHospital Treatment Airway, gag reflex, mental status, are they protecting their airway & secretions

Breathing, RR, pulse ox, ETCO2, place on O2 PRN

Circulation, skin temp & color, HR, rhythm, BP, cap refill, place on monitor (bc of possible dysrhythmias), dry pits, low BP  admin fluids Disability / neuro – mental status, check blood glucose, pupils

Expose –temperature , skin temp, color –actively cool if needed – evaporative cooling Timing and Hx of Exposure are important to document Diphenhydramine • Reaches plasma peak conentrations in 2‐3 hrs • Can see significant dermal absorption, especially with prolonged exposure or application on abraded skin • Can last 3‐24 hrs • Hepatic metabolism, any Asian pts can metabolize 2x as fast as Caucasian pts (making them less sensitive to psychomotor & sedating effects. • Well absorbed following oral administration Transport Considerations

• Any evidence of rhabdo, co‐ingestion, other bottles, self harm, heat or cool in home • Give activated charcoal if w in the hr and controlling airway and secretions • (if they looked bummed bc they know that have to drink this stuff then give) • Physostigmine ‐ controls agitation & delirium better than benzos • Sodium Bicarb – admin for QRS > 120 & hypotension • Can always call Poison Control THE END

• Questions… ? • Comments… ? • Snide Remarks… ?