Atropine
Atropine Sulfate
Atropine is commonly classified as an anticholinergic or antiparasympathetic (parasympatholytic) drug. Atropine can be used as a diagnostic aid in radiologic examination of the gastrointestinal tract. Atropine relaxes bronchial and lower esophageal sphincter muscle tone, reduces salivary, respiratory, and gastrointestinal secretions and slows the movement of the gastrointestinal tract. It is also used to temporarily increase heart rate in the bradycardia associated with vagal stimulation from pain or distention.
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Atropine Dosing for Endoscopy Adult - Initial dose: 0.4-0.6 mg
- Additional doses: 0.4-0.6 mg
- Onset of action: 45-60 seconds
- Peak effect: 2 minutes
- Duration of effect: 1-2 hours
Pediatric* *Dosing information for atropine in pediatric populations has not been well studied. |
- The fatal adult dose of atropine is not known; 200 mg doses have been used and doses as high as 1000 mg have been given.
- In pediatric populations, 10 mg or less may be fatal.
- With a dose as low as 0.5 mg, undesirable minimal symptoms or responses of overdosage may occur. These increase in severity and extent with larger doses of the drug (excitement, hallucinations, delirium and coma with a dose of 10 mg or more).
Symptoms- Toxic doses lead to palpitations, restlessness and excitement, hallucinations, delirium and coma.
- Depression and circulatory collapse occur only with severe intoxication. In such cases, blood pressure declines and death due to respiratory failure may ensue following paralysis and coma.
Treatment
- A short acting barbiturate or diazepam may be given as needed to control marked excitement and convulsions. Large doses for sedation should be avoided because central depressant action may coincide with the depression occurring late in atropine poisoning.
- Physostigmine, given as an atropine antidote by slow intravenous injection of 1 to 4 mg (0.5 to 1 mg in pediatric populations), rapidly abolishes delirium and coma caused by large doses of atropine. Since physostigmine is rapidly destroyed, the patient may again lapse into coma after one to two hours, and repeated doses may be required.
- Artificial respiration with oxygen may be necessary.
- Ice bags and alcohol sponges help to reduce fever, especially in pediatric populations.
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- Carcinogenesis, mutagenesis, impairment of fertility: Studies have not been performed to evaluate the carcinogenic or mutagenic potential of Atropine or its potential to adversely affect fertility.
- Use in pregnancy: Pregnancy Category C. Animal reproduction studies have not been conducted with atropine. It also is not known whether atropine can cause fetal harm when given to a pregnant woman or can affect reproduction capacity. Atropine should be given to a pregnant woman only if clearly needed.
- Use in pediatric patients: Safety and effectiveness in pediatric populations have not been established.
- Use in geriatric patients: There is no clinical experience identifying differences in response between elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
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- Most of the side effects of atropine are directly related to its antimuscarinic action. Dryness of the mouth, blurred vision, photophobia and tachycardia commonly occur with chronic administration of therapeutic doses.
- Anhidrosis may occur and produce heat intolerance or impair temperature regulation in persons living in a hot environment.
- Constipation and difficulty in micturition may occur in elderly patients .
- Occasional hypersensitivity reactions have been observed, especially skin rashes which in some instances progressed to exfoliation.
- Adverse effects following single or repeated injections of atropine are most often the result of excessive dosage. These include palpitation, dilated pupils, difficulty in swallowing, hot dry skin, thirst, dizziness, restlessness, tremor, fatigue and ataxia.
- Toxic doses lead to marked palpitation, restlessness and excitement, hallucinations, delirium and coma.
- Depression and circulatory collapse occur only with severe intoxication. In such cases, blood pressure declines and death due to respiratory failure may ensue following paralysis and coma.
- Atropine should be used with caution in all individuals over 40 years of age.
- Conventional systemic doses may precipitate acute glaucoma in susceptible patients, convert partial organic pyloric stenosis into complete obstruction, lead to complete urinary retention in patients with prostatic hypertrophy or cause inspissation of bronchial secretions and formation of dangerous viscid plugs in patients with chronic lung disease.
- Systemic doses slightly raise systolic and lower diastolic pressures and can produce significant postural hypotension. Such doses also slightly increase cardiac output and decrease central venous pressure.
- Occasionally, therapeutic doses dilate cutaneous blood vessels, particularly in the "blush" area (atropine flush), and may cause atropine "fever" due to suppression of sweat gland activity in infants and small children.
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- Atropine is a highly potent drug and caution is essential to avoid overdose, especially with intravenous administration.
- Pediatric populations are more susceptible than adults to the toxic effects of anticholinergic agents.
- Atropine I.V. decreased the rate of mexiletine (Class IB anti-arrhythmic) absorption without altering the relative oral bioavailability; this delay in mexiletine absorption was reversed by the combination of atropine and intravenous metoclopramide during pretreatment for anesthesia.
- Atropine is not removed by dialysis.
- Do not administer unless solution is clear and seal is intact. Discard unused portion.
- Glucagon has been shown to be as effective as anticholinergic drugs (e.g. atropine) in inhibiting the movement of the gastrointestinal tract prior to endoscopic examination.
- The use of the two agents together may result in increased side effects.
- Buscopan may also be used as an alternative medication, although its use is more common in Europe than in the U.S.
- Atropine generally is contraindicated in patients with glaucoma, pyloric stenosis or prostatic hypertrophy, except in doses ordinarily used for preanesthetic medication.
- Extreme care must be used in patients with tachyarrhythimia
SourcesAtropine Sulfate Injection, Solution [package insert], Hospira, Inc., September 2006.
http://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?id=1628&type=display Glucagon for Injection: Information for the Physician, Eli Lilly, 2003.
Kost M. Moderate Sedation/Analgesia: Core Competencies for Practice, 2nd Ed. St. Louis, MO: Saunders, St. Louis; 2004:120-1.
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Last Updated October 9, 2008