Atropine
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More Specific Terms
Indications
-
- pre-operative medication to reduce salivation & excessive secretions of the respiratory tract
- used to prevent cholinergic effects during surgery
-
- treatment of choice for symptomatic bradycardia (class I)
- may be beneficial (class IIa) for treatment of AV block at the nodal level or ventricular asystole
- ophthalmic agent ( mydriatic & cycloplegic agent) for examination of the retina & optic disc
- diarrhea: used in combination with diphenoxylate in Lomotil
Contraindications
- asthma
- narrow angle glaucoma ( ophthalmic)
- atropine is no longer recommended for pulseless electrical activity ( PEA)
- atropine may be best avoided in patients with
- type II second degree heart block
- new onset type III heart block with wide QRS complexes,
- these rhythms are frequently secondary to anteroseptal myocardial infarction, resulting in a conduction system defect at the His-Purkinje level
- diminished vagal tone will not help these patients
- pregnancy category = c
- safety in lactation = -
- safety in lactation = ?
Dosage
- 0.4-0.6 mg PO, SC, IM, IV every 4-6 hours
- pre-operative: give 30-60 minutes prior to induction of anesthesia
- ACLS: 1 mg IV, repeat in 3-5 minutes, max 0.03 mg/kg
- endotracheal: 2-2.5 x the IV dose in 10 ms of normal saline
- Tradenames: Isopto Atropine, Atropair, Atropine-Care. Mydriasis: 1 drop QD- TID for 7-14 days Cycloplegia: 1 drop QD- TID for 5-10 days
- 0.5 % 1.2%
Pharmacokinetics
- well absorbed throught the GI tract:
- absorbed in upper small intestine
- peak plasma levels in 1 hour
- IM injection: peak plasma levels in 30 min
- endotrachial administration:
- absorbed well through the endotracheal route
- peak plasma concentrations in 1.5-4 hours
- a total dose of 3 mg produces total vagal block in humans
- limited amounts cross the blood-brain barrier
- maximal mydriasis in 30-40 minutes with duration of action of 7-12 days
- maximal cycloplegia in several hours with duration of action of 2 weeks
Adverse-effects
- common (> 10%)
- dry, hot skin
- impaired GI motility
- constipation
- dry mouth & throat
- irritation at site of injection
- dry nose
- decreased sweating
- not common (1-10%)
- photophobia, decreased flow of breast milk, dysphagia
- uncommon (< 1%)
- orthostatic hypotension, tachycardia, palpitations, ventricular fibrillation, confusion, drowsiness, ataxia, fatigue, delirium, headache, memory impairment, restlessness, rash, nausea/vomiting, difficulty urinating, tremor, weakness, intraocular pain, blurred vision, mydriasis
- other [1]
- toxicity
Drug-interactions
- additive effects when co-administered with other anticholinergic agents
- may alter absorption of other drugs
Mechanism-of-action
- antimuscarinic agent that competitively inhibits action of acetylcholine
- dose-dependent anti- muscarinic activity
- relative degree of sensitivity
- secretions of salivary, bronchial & sweat glands
- pupillary dilatation
- ocular accomodation
- increased heart rate
- contraction of the detrussor muscle of the bladder & smooth muscle of the GI tract
- gastric acid secretion & motility
- blocks action of acetylcholine at muscarinic receptor sites in the smooth muscle of the iris
More General Terms
- belladonna alkaloid
- parasympatholytic (anticholinergic, antimuscarinic agent)
- mydriatic agent
- cycloplegic agent
- antidote
Additional Terms
Internet Database
References
- Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- Kaiser Permanente Northern California Regional Drug Formulary, 1998
- Prescriber's Letter 9(5):28 2002
- Medical Knowledge Self Assessment Program (MKSAP) 14, American College of Physicians, Philadelphia 2006
- American Heart Association Guidelines for CPR and Emergency Cardiovascular Care Oct. 18, 2010 Comparison Chart of Key Changes [1]
