Atropine Flashcards
What are the indications for atropine?
In cardiology
Bradycardia due to overdose of beta-blockers or adenosine
Useful in treating Mobitz Type 1 and a 3rd degree heart block with a high purkinje or AV-nodal escape rhythm
Bradycardia following an MI
In ophthalmology
- cycloplegia
- anterior uveitis
See BNF for more
What is the typical dose when it is being used to treat symptomatic bradycardia due to beta blocker overdose?
0.5-1.2 mg (in adults)
0.02mg/kg - max 1.2mg (in children)
What is the typical dose when it is being used to treat excessive bradycardia due to beta blocker overdose?
0.6-2.4mg in divided doses (max. per dose 600 micrograms) - ADULTS
What is the pharmacodynamic of atropine?
Ach antagonists
Inhibits M1, 2, 3, 4, 5 receptors
Causes increased firing of the SAN
What is the pharmacokinetic of atropine?
Rapidly and well absorbed after IM injection
Protein binding = 14 to 44%
Half life = 2-4 hours
Metabolised in liver via enzyme hydrolysis
13 to 50% is excreted unchanged in the urine
What are the contraindications for atropine?
-Myasthenia gravis
-Paralytic ileus
-Angle-closure glaucoma
-Severe UC
-GI obstruction
-Toxic megacolon
What are the specific side effects for atropine?
-dizziness
-abdominal distention
-arrythmias
-tachycardia
-anxiety
-photophobia
-hallucinations
-skin reactions
-mydriasis
-taste loss
-thirst
Is any monitoring required for atropine?
Yes
Shorter duration of action than neostigmine
Late unopposed bradycardia may result
Close monitoring of the patient is necessary.
What advice should patients who have just received an atropine injection be given about driving?
They should not drive as it may cause confusion or blurred vision
What are the significant interactions for atropine?
Atropine + phenylephrine = increased risk of severe HTN
Atropine + clozapine = increased risk of constipation - concurrent use that increase risk of intestinal obstruction
What can high doses of atropine cause?
Palpitation
Dilated pupils (mydriasis)
Thirst
Difficulty swallowing
Hot dry skin
Dizziness
Restlessness
Tremor
Fatigue
What can toxic doses of atropine cause?
Restlessness and excitement
Hallucinations
Delirium
Coma
What can severe intoxication of atropine cause?
Circulatory collapse, leading to a decline in blood pressure and respiratory failure that may ensue in death following paralysis and coma
Sources
https://www.medicines.org.uk/emc/files/pil.5000.pdf
https://go.drugbank.com/drugs/DB00572
https://bnf.nice.org.uk/drugs/atropine-sulfate/#indications-and-dose
