Atropine Flashcards
What is the mechanism of action of atropine?
Muscarinic acetylcholine antagonist that blocks vagal input to SA and AV nodes
How does atropine counteract bradycardia?
By increasing cardiac conduction
What effect can atropine have on the AV block?
It can reverse AV block and restore normal sinus rhythm
How long is the effect of atropine?
Short-lived
Why is the effect of atropine short lived?
Due to short half life
What are the routes of delivery of atropine?
PO
IV
IM
Who should administer IV atropine?
Only those trained in its use
What are the indications for the use of atropine?
- Bradycardia
- Organophosphorus poisoning
- GI smooth muscle spasm
What dose of atropine is used for bradycardia following beta-blocker overdose?
3mg IV
What does of atropine is used for intra-operative bradycardia?
300-600mcg IV, larger in emergency
What dose of atropine is used for bradycardia following MI?
500mcg IV
When is atropine contraindicated?
- Myasthenia gravis
- Narrow-angle glaucoma
- Pyloric stenosis
- Prostatic hypertrophy
Who should atropine be avoided in?
- Children
- Elderly
- Down syndrome
Who should atropine be used with caution in?
- Cardiovascular disease
- Arrhythmias
- Autonomic neuropathy
- Individuals susceptible to angle-closure glaucoma and hypertension
What might atropine interact with?
- SSRIs
- TCAs
- Haloperidol
- Other anti-muscarinic agents
- Codeine
- Levodopa
What might happen if atropine is given with SSRIs?
Increased antimuscarinic side effects of atropine
What might happen if atropine is given with TCAs?
Increased antimuscarinic side effects of atropine
What might happen if atropine is given with haloperidol?
Increased antimuscarinic side effects of atropine
What might happen if atropine is given with other anti-muscarinic agents?
Increased antimuscarinic side effects of atropine
What might happen if atropine is given with codeine?
Increased antimuscarinic side effects of atropine
What might happen if atropine is given with levodopa?
Reduced absorption of atropine
What monitoring is required with atropine?
Close monitoring of vital signs and ECG in emergency use of atropine during bradycardia
Why is close monitoring required when atropine is being used for bradycardia?
The effects of atropine wear off quickly due to its short half life
What are the common side effects of atropine?
- Increased HR
- Reduction in secretions, e.g. dry mouth
- Urinary retention
- Dilated pupils resulting in blurred vision
- Constipation
Why is patient counselling sometimes not possible in atropine?
As the drug is given in emergency situations, e.g. life threatening bradycardia
What counselling should be given to patients started on atropine in a non-emergency setting?
Inform patient atropine tablets should be swallowed whole, and warn patients about the anti-muscarinic side-effects
