Toxicology Flashcards
Learn about drugs, don't do drugs. -Mike 2022
What is the generalized mechanism of direct-action cholinergic drugs?
Bind to cholinergic receptors, stimulating the organ in a similar way as ACh
What is the generalized mechanism of indirect-action cholinergic drugs?
Inhibit the enzyme ‘acetylcholinesterase,’ resulting in more ACh available at the receptors
Between direct and indirect-action cholinergic drugs, which category is best suited for treating Alzheimer’s?
Indirect-action:
More sustained levels of ACh in the nervous system leads to improved neurotransmission
What does the “S” in “SLUDGE M” stand for?
Salivation
What does the “L” in “SLUDGE M” stand for?
Lacrimation
What does the “U” in “SLUDGE M” stand for?
Urination
What does the “D” in “SLUDGE M” stand for?
Diaphoresis
What does the “G” in “SLUDGE M” stand for?
Gastrointestinal Discomfort
What does the “E” in “SLUDGE M” stand for?
Emesis
What does the “M” in “SLUDGE M” stand for?
Miosis (Pupil constriction)
Three FDA-approved cholinergic drugs for treating Alzheimer’s
Donepezil, Rivastigmine, Galantamine
Common causes of cholinergic toxicity
Exposure to insecticides or military nerve agents
Why does cholinergic toxicity cause sweating (a sympathetic response)?
ACh acts on muscarinic receptors of sweat glands
What is ACh?
Neurotransmitter for PNS and SNS
What are some treatments for cholinergic toxicity as per ALS PCS?
Atropine, Pralidoxime, Diazepam
(Pralidoxime is the main antidote used in definitive care)
Why is seizure activity/muscle twitching common in cholinergic toxicity?
Increased ACh in synapses means increased nervous system excitability
What is the mechanism of action of anticholinergic drugs?
Anticholinergic drugs block the muscarinic and nicotinic receptors so that ACh cannot act on them
What toxidrome causes a “wet” patient?
Cholinergic
What toxidrome causes a “dry” patient?
Anticholinergic
What are the key signs of anticholinergic toxicity?
-Red, hot, dry skin
-Tachycardia
-Dry mouth
-Constipation
-Mydriasis (Pupil dilation)
-Blurred vision
-Altered LOA
What are some examples of anticholinergic drugs?
-Diphenhydramine (Allergic reactions, sleep aid)
-Dimenhydrinate (N/V, motion sickness)
-Atropine (Given by ACPs to treat bradycardia)
-Atrovent (Bronchodilator used to treat COPD)
-Scopolamine (N/V, motion sickness, commonly used by SCUBA divers thru transdermal patches to aid with seasickness)
-TCAs (Uncommon anti-depressant, stupid easy to OD on)
-Antipsychotics (It lives in my drywall)
-Jimson Weed (silly flower that is smoked for hallucinogenic properties)
What is considered a lethal dose of TCAs?
10-20mg/kg
What is the mechanism of action found in a TCA overdose?
Loss of vascular tone following muscarinic and alpha receptor blockage. Sodium channel is also blocked, leading to signature prolonged QT intervals.
What are the signs and symptoms of a TCA overdose?
- Hx of TCA use
- Red, hot, dry skin
- Tachycardia
- Loss of bowel sounds (If you insist, Mike)
- Prolonged QT intervals with risk of lethal arrhythmia