Oral: Used to relieve dry mouth after head and neck radiation
What are the actions of Cholinergic Blocking Agents (Parasympathomimetics)?
Inhibit the action of ACH receptors
What systems are affected by Cholinergic Blocking Agents (Parasympathomimetics) and by what action is this achieved?
Affects the heart, respiratory tract, GI tract, bladder, eye, and exocrine glands
By allowing the sympathetic nervous system to dominate
What are the effects of Cholinergic Blocking Agents (Parasympathomimetics)?
Decrease GI motility, decrease salivation, dilation of pupils, increase in pulse rate
Anticholinergics are widely used state some of the different uses:
Pre - op medications
Bradycardia
GI/Urinary antispasmodic
IBS
Motion sickness
Anticholinergics
What are different souces of Atropine?
Source (Alkaloid)
Atropa Belladona
Daktura Stramonium (jamestown weed)
True or False:
The blockade of Atropine is competitive and reversible. Give an explanation.
True
If the concentration of acetylcholine in the vicinity of the blocked receptor can be increased, acetylcholine will displace atropine and transmission will be restored
What are the actions of Atropine?
Inhibits ACH
Blocks vagal effects on SA node and AV node
Increases conduction and HR
What is the prototype blocker of muscarinic receptors?
Atropine
Hallucinatory effects of atropine and its relatives are often sought out by recreational drug users
Atropine Effects (5):
Mad as a hatter
Blind as a bat
Dry as a bone
Red as a beet
Hot as a pistol
Mad as a Hatter effect of Atropine:
Drug-induced delirium is one of the most dangerous aspects of atropine poisoning in adults
Result in self-destructive acts, such as leaping out of windows or pulling out intravenous tubing.
Blind as a Bat, the three effects Atropine has on vision:
Cholinergic tone to the sphincter iridis muscle of the iris tends to contract the pupil
Interruption of that tone leads to pupillary dilation (mydriasis)
Unrelenting mydriasis results in photophobia
Dry as a Bone effect of Atropine:
Manifested by a blockade of cholinergic tone to the salivary glands
Decreased salivation, dry mouth, intense thirst and difficulty in swallowing
Skin is also dry because of a blockade of sweating
Red as a Beet effect of Atropine:
Mechanism of this response is unknown
Flushing
Not attributed to blockade of muscarinic receptors
Hot as a Pistol effect of Atropine:
Elevated body temperature
May reach life-threatening levels
Atropine (Dosing)
Low Dose 0.5mg symptoms:
Slight decline in HR, inhibition of sweating, some dry mouth
Atropine (Dosing)
1 mg Dose symptoms:
Increased heart rate, definite dry mouth, thirst
Atropine (Dosing)
2 mg Dose symptoms:
Rapid heart rate, palpitations, dilated pupils, blurring of near vision
Atropine (Dosing)
5 mg Dose symptoms:
Rapid HR, palpitations, dilated pupils, blurring of near vision, difficulty speaking, headache, dry hot skin reduced intestinal peristalsis
Atropine (Dosing)
10 mg Dose symptoms:
Rapid HR, palpitations, dilated pupils, difficulty speaking, headache, dry hot skin reduced intestinal peristalsis, very blurred vision, ataxia, reslestness and hallucinations, possible coma
Anticholinergic
What is the method of action of Dicyclomine (Bentyl)?
Inhibits ACH on muscarinic receptors and decreases GI motility
Anticholinergic
What are the uses of Dicyclomine (Bentyl)?
Irritable Bowel Syndrome
Constipation, urinary retention and dry mouth
What is the dose for Dicyclomine (Bentyl)?
10-20 mg PO TID AC
PO-orally
TID-3 X Day
AC-before meals
Anticholinergic
What is the method of action of Glycoperalate (Robinul) and what are it's uses?
Similar to bentyl method of actio
inhibits ACH on muscarinic receptors and decreases GI motility
Uses: Pre-op to decrease secretions and GI disorders
What are the doses of Glycopralate (Robinul)?
IV and Oral (1-2 mg)
Also used when dislodging something stuck in the throat
Effect of a Scopolamine Patch:
Give examples:
ACH benefit the CNS and help for motion sickness
Dramamine and Bonine oral
Crosses the blood brain barrier
What are some side effects of Scopolamine Patch?
Dry mouth, visual disturbances, and pupil dilation
Contraindications to the Anticholinergics:
Narrow angle glaucoma
Hypertrophy of the prostate
Atony of the bladder
Atony of the GI tract
Careful in elderly
Other Drugs with Anticholinergic Effects (other classes):
Tricyclic antidepressants
Phenothiazine antipsychotics
Dibenzoxaoine antipsychotic agents
H1 receptor blocking agents
What drugs can be used to alleviate the symptoms associated with anticholinergic effects?
Muscanrinic agonists:
Pilocarpine
Bethanechol
NMB
Neuromuscular-Blocking Agent
Cholinergic receptors are close to the enzyme _______________.
acetylcholinesterase
Acetylcholinesterase is an enzyme that is responsible for rapid hydrolysis of ACH to __________ and _________.
acetic acid
choline
True or False:
Choline re-enters motor nerve endings to again participate in the synthesis of new acetylcholine.
True
Rapid hydrolysis of ______ prevents sustained depolarization.
ACH
Nicotinic Acetylcholine Receptor (nAChR)
Up-regulation can cause:
Succinylcholine (Quelicin)
Onset of action?
Duration of action?
Short acting
Onset of action: 30-60 seconds
Duration of action: 5-8 minutes
What is the dosage of Succinylcholine (Quelicin) when used in Rapid sequence Intubation (RSI)?
Intermittent?
Continuous?
Rapid Sequence Intubation (RSI): 1mg/kg
Intermittent I.V. dose: 0.6mg/kg over 10-30 seconds, max dose 150mg
Continuous I.V. dose: 2.5mg/min; not routinely done
What are adverse effects of Succinylcholine?
Respiratory Depression
Anaphylaxis (rare) - less than 1%
Cardiac Arrest
Bradycardia
Hypotension
Hyperkalemia
Non-Depolarizing NMBs
Rocuronium (Zemuron)
Mivacurium ( Mivacrom)
Cisatracurium (Nimbex)
Vecuronium (Norcuron)
Pancuronium (Pavulon)
Atracurium Besylate (Tracurium)
Rocuronium
Usage:
Type of acting:
Onset:
Duration of action:
Usage:I.V. use
Type of acting: Short acting
Onset: 1-3 minutes
Duration of action: 31 minutes
Used in Rapid Sequence Intubation (RSI)
Precautions when using Rocuronium:
Pulmonary disease
Hepatic impairment
Rocuronium
Dose:
Diluents:
Adverse Effects:
Dose: RSI: 0.6-1.2 mg/kg - usually a bolus
Continuous IV infusion: .01-.012 mg/kg/min - Not routine
Diluents: NS, D5W
Adverse Effects: Hypotension, HTN
Primary use of Mivacurium (Mivacrom):
Induction of neuromuscular blockade, During surgery as an adjunct to general anesthesia and to facilitate tracheal intubation or mechanical ventilation
Intial Dose of Mivacurium used for intubation:
initial, for intubation, 0.15 mg/kg IV bolus over 5-15 sec OR 0.2 mg/kg IV bolus over 30 sec OR 0.25 mg/kg IV bolus in divided doses (0.15 mg/kg followed in 30 sec by 0.1 mg/kg)
Not used in patients with cardiac issues (arrythmias)
Maintenance dosage of Mivacurium:
maintenance, 0.1 mg/kg IV bolus 15-25 min after initial dose
maintenance, 9-10 mcg/kg/min continuous IV infusion after initial dose, upon early evidence of spontaneous recovery
maintenance, 4 mcg/kg/min continuous IV infusion if initiated simultaneously with administration of initial dose
Cisatracurium (Nimbex)
Type of use
Quikness of action:
Onset of action:
Duration of action:
I.V. use only
Intermediate acting
Onset of action: 2-3minutes
Duration of action: 30-40 minutes
What is the drug of choice when dealing with:
Significant renal dysfunction (CrCl <30m/min)
Hepatic Failure
Concurrent corticosteroid administration (>72 hours)
History of asthma or bronchospasm?