Atropine |

Atropine

Class:	Parasympathetic blocking agent (blocks muscarinic receptor sites)
Actions:	Blocks parasympathetic stimulation of SA node Increases automaticity of SA node (*positive chronotropic*) Decreases AV conduction time
Indications:	Symptomatic sinus bradycardia (1^st line drug of choice according to ACLS) Asystole (2nd line drug of choice after epinephrine according to ACLS) 1^st degree or 2^nd degree (Mobitz type I) AV blocks–only if symptomatic Organophosphate poisoning (antidote) Ophthalmic agent to produce mydriasis and paralysis of ciliary muscle (responsible for accommodation) Intestinal hypertonicity & hypermotility Preoperative agent to decrease body secretions and intestinal motility during surgery
Pharmacokinetics:	Peak: 2 – 4 minutes IV Half-Life: 2 – 3 hours
Adverse Effects:	ANTICHOLINERGIC AGENT! Dry mouth, thirst, dysphagia, nausea, vomiting, constipation, paralytic ileus Tachycardia Dry mucous membranes, flushing of skin (red, dry) Urinary retention Mydriasis, blurred vision, photophobia Headache, dizziness, ataxia, irritability, drowsiness, confusion, disorientation Drying and thickening of bronchial secretions
Signs of Toxicity:	Fever, convulsions, ventricular tachycardia
Contraindications:	Avoid in hypothermic bradycardias! Not useful in Mobitz Type II or 3^rd degree AV blocks (wide QRS's) Hypersensitivity to belladona alkaloids Angle closure glaucoma Obstructive uropathies (prostatic hypertrophy) Paralytic ileus GI bowel obstruction Use cautiously in patients with asthma or COPD Use cautiously in patients with myocardial ischemia or infarction. Safety during pregnancy or lactation not established (Category C).
Dosages & Routes:	IV bolus: (for bradycardias or heart blocks) 0.5 mg IV push, repeated every 3-5 minutes until maximum dose of 3 mg. IV bolus: (for *asystole) 1 mg IV or IO every 3-5 minutes for maximum of 3 doses (3 mg). IV bolus:* (for organophosphate poisoning) 2 – 4 mg or higher (may need to be repeated periodically)
Nursing Implications:	Drug Interactions: 1) Significant potentiation of anticholinergic effects with amantadine, antihistamines, tricyclic antidepressants, quinidine, disopyramide; 2) Atropine decreases the effects of levo-dopa; 3) Atropine enhances extrapyramidal effects with methotrimeprazine; 4) Antipsychotic effects of phenothiazines are decreased due to decreased absorption. Monitor apical pulse prior to administration. Cardiac monitor should be used on patients receiving atropine IV boluses. Doses of 0.5 mg or less may result in paradoxical slowing of heart rate. Eye preparations generally used only for procedures and have only localized effects on optic muscles. Chronic use of eye preparations may result in systemic anticholinergic symptoms which may be hazardous in infants and children. Atropine can be administered via endotracheal tube in dose of 2-3 mg diluted in 10 ml H₂O, but intraosseous route is preferred over endotracheal tube if IV access cannot be achieved. Older adults and debilitated patients may be more vulnerable to CNS disturbances from atropine. Monitor temperature in infants and children for "atropine fever". Measures to relieve dry mouth: adequate fluid hydration, oral hygiene (don't use alcohol based mouthwashes), ice chips, sugarless gum, or hard candies to suck on. Avoid driving or operating heavy machinery while under the influence of atropine. Reduce lighting to decrease photophobia. Monitor GI motility (BMs and flatus) and urine output while patient is receiving atropine. Atropine is a common pre-operative agent, and can be given IM, SC, PO, or IV.

References:

American Heart Association. (2006). Handbook of Emergency Cardiac Care (p. 46). Salem, MA: AHA.

Lehne, R.A. (2010). Pharmacology for nursing care (7th ed., pp. 123-125). St. Louis: Saunders Elsevier.

Wilson, B.A., Shannon, M.T., Shields, K.M., & Stang, C.L. (2007). Prentice Hall Nurse's Drug Guide 2007 (pp. 139-142). Upper Saddle River, NJ: Pearson Prentice Hall.

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