Atropine

Class: Antimuscarinics/Antispasmodics
VA Class: AU350
CAS Number: 51-55-8
Brands: AtroPen, Sal-Tropine

• Pesticide and Chemical Warfare Agent Poisoning


• 
  

  Primary protection against exposure to chemical nerve agents and insecticide poisoning is the wearing of protective garments (e.g., specialized masks).¹⁰⁵

  
  


• 
  

  Do not rely solely on antidotes such as atropine and pralidoxime to provide complete protection from chemical nerve agents and insecticide poisoning.¹⁰⁵

  
  


• 
  

  Seek immediate medical attention after injection with an atropine auto-injector.¹⁰⁵

  
  

Introduction

Antimuscarinic; a naturally occurring tertiary amine.

Uses for Atropine

Surgery

To inhibit salivation and excessive secretions of the respiratory tract (antisialogogue).^{b f} However, current surgical practice (e.g., using general anesthetics that do not stimulate salivary and tracheobronchial secretions) has reduced the need to control excessive respiratory secretions during surgery.^b

To prevent other cholinergic effects during surgery (e.g., cardiac arrhythmias, hypotension, bradycardia) secondary to visceral or ocular traction (resultant vagal stimulation), carotid sinus stimulation, or concomitant drugs (e.g., succinylcholine).^{b f}

To block adverse muscarinic effects of anticholinesterase agents that are used after surgery to terminate curarization.^{b f}

Ineffective for preventing acid-aspiration pneumonitis† during surgery.^b

CPR and Cardiac Arrhythmias

For its anticholinergic positive chronotropic effect in ACLS during CPR.^{b 106 108}

Treatment of symptomatic sinus bradycardia (e.g., that accompanied by hemodynamic compromise or by frequent ventricular ectopic beats).^{b 106 108} Reverses cholinergically mediated decreases in heart rate, systemic vascular resistance, and BP.^{b 106 108}

Treatment of symptomatic bradycardia caused by AV block at the nodal level or by vagal stimulation (e.g., induced by suctioning or endotracheal intubation).^{106 108} Do not rely on atropine for AV block at or below the His-Purkinje level (type II 2nd-degree AV block or 3rd-degree AV block, including 3rd-degree AV block accompanied by new wide QRS complexes); do not delay pacing, these patients require immediate pacing.¹⁰⁶

In children, for treatment of bradycardia secondary to increased vagal activity or primary AV block, however, only if manifestations of hemodynamic compromise persist despite support of adequate oxygenation and ventilation and chest compressions (if indicated); bradycardia may respond to these latter measures alone.^{b 106 108}

In neonates, lack of evidence of usefulness in the acute phase of CPR; therefore, current guidelines for ACLS no longer include recommendations for such use.^{b 106 108} Drugs rarely are needed during resuscitation of neonates; establishing adequate ventilation is most important measure to correct bradycardia.^{106 108}

Treatment of asystole;^{b 106 108} efficacy in children is unclear.^{b 108}

Treatment of pulseless electrical activity (PEA) if PEA rate is slow.^{b 106 108}

Treatment of sustained bradycardia and hypotension associated with nitroglycerin use in MI and for nausea and vomiting associated with morphine use in MI.^b

Treatment of sudden-onset sinus node suppression complicated by hypotension or ventricular irritability.^b

Treatment of chronic symptomatic sinus node dysfunction when a permanent pacemaker is not implanted.^b

Cautiously in the presence of acute myocardial ischemia or MI because heart rate is a major determinant of myocardial oxygen requirements.^{b 106 108}

Cautiously and with appropriate monitoring following cardiac transplantation; may be ineffective due to lack of vagal innervation in transplanted heart.¹⁰⁶ Risk of paradoxical slowing of the heart rate and high-degree AV block in patients receiving atropine after cardiac transplantation.¹⁰⁶

VF and VT have occurred rarely following IV administration of atropine sulfate.^{b 108}

Diagnostic Uses in Cardiac Disorders

Diagnosis of sinus node dysfunction†.^b

Evaluation of CAD during atrial pacing†.^b

Diagnosis of MI in Wolff-Parkinson-White syndrome†.^b

Pesticide Poisoning

Concomitantly with a cholinesterase reactivator (pralidoxime chloride) to reverse muscarinic effects associated with toxic exposure to organophosphate anticholinesterase pesticides.^{103 105 b}

Reversal of muscarinic effects associated with toxic exposure to carbamate anticholinesterase pesticides.^{105 b l} Concomitant cholinesterase reactivator (pralidoxime chloride) therapy may not be necessary.^{b l}

A challenge (test) dose of atropine may be useful in diagnosing cholinergic poisoning†.^l Failure of the challenge dose to elicit typical antimuscarinic effects (e.g., mydriasis, tachycardia, dry mucous membranes) strongly suggests the presence of organophosphate or carbamate poisoning.^l

Chemical Warfare Agent Poisoning

Concomitantly with a cholinesterase reactivator (pralidoxime chloride) to reverse muscarinic effects associated with toxic exposure to organophosphate anticholinesterase nerve agents (e.g., sarin, soman, tabun, VX [methylphosphonothioic acid]) in the context of chemical warfare or terrorism.^{b 101 102 103 104 105}

Initial management of nerve agent poisoning includes aggressive airway control and ventilation (administration of nebulized β-adrenergic agonist [e.g., albuterol] and antimuscarinics [e.g., ipratropium bromide] may be necessary), and administration of atropine and pralidoxime chloride;^{101 102 103} diazepam may be needed for seizure control.¹⁰¹

Mushroom Poisoning

Treatment of muscarinic effects associated with toxic ingestion of mushrooms containing muscarine^{f l} (e.g., certain members of the Clitocybe and Inocybe genera).^l However, substantial toxicity is uncommon, and supportive symptomatic care (e.g., atropine) rarely is necessary.^l

Although certain members of the Amanita genus also contain muscarine, the amount is limited.^l

Radiographic Uses

Facilitation of hypotonic duodenography^e by reducing motility and spasm; however, glucagon appears to be more effective and generally is preferred.^b

Facilitation of hypotonic contrast examination of the colon^e by reducing motility and spasm; however, glucagon appears to be more effective and generally is preferred in these examinations.^b

Has been used to increase visualization of the urinary tract in excretion urography.^{b e}

Bronchospasm

Has been used by oral inhalation as a quick-relief bronchodilator for the short-term symptomatic treatment of acute symptoms and exacerbations of reversible bronchospasm associated with bronchial asthma, bronchitis, and COPD; however, a solution of the drug for oral inhalation no longer is commercially available in the US.^b Ipratropium bromide currently is the anticholinergic of choice when such therapy is indicated.^{h i}

Has been used in a combined regimen of oral inhalation and IM injection to prevent bronchospasm.^{b c}

GI Disorders

Has been used as an adjunct in the treatment of peptic ulcer disease;^{b c} however, no conclusive data that it aids in the healing, decreases the rate of recurrence, or prevents complications of peptic ulcers.^b

With the advent of more effective therapies for the treatment of peptic ulcer disease, antimuscarinics have only limited usefulness in this condition.^b

Has been used in the treatment of functional disturbances of GI motility such as irritable bowel syndrome;^{b g} however, efficacy is limited.^b Use only if other measures (e.g., diet, sedation, counseling, amelioration of environmental factors) have been of little or no benefit.^b

GU Disorders

Adjunctive therapy in the management of hypermotility disorders of the lower urinary tract.^b May provide symptomatic relief, but the underlying cause should be determined and specifically treated.^b

With the exception of uninhibited or reflex neurogenic bladder, there is generally little evidence to support the use of antimuscarinics in the treatment of various GU disorders.^c

Biliary Disorders

Do not rely on for relief of biliary tract disorders (e.g., combined with opiates for biliary colic) because of weak biliary antispasmodic action.^b

Pancreatitis

Has been used to decrease gastric and pancreatic secretions in acute pancreatitis, but little evidence of benefit.^b

Atropine Dosage and Administration

Administration

Administer by sub-Q, IM, or IV injection.^{105 106 108 b e f g}

For ACLS during CPR, may be administered via an endotracheal tube^{b 106 108 f} or by intraosseous infusion†^{b 106 108} when IV injection is not possible. Although endotracheal administration is possible, IV or intraosseous† drug administration is preferred because of more predictable drug delivery and pharmacologic effect.¹⁰⁶

For bronchodilation, has been administered via oral inhalation, via nebulization, or by injection.^b

IV Injection

CPR: When a vein has not been cannulated prior to the arrest, a peripheral vein is preferred because central venous access requires interruption of chest compressions.^{b 106}

If a central venous catheter is already in place at the time of arrest, it can be used because of more rapid onset (in adults), more secure access to circulation, and avoidance of tissue infiltration.^{b 106 108} Central venous line placement should be avoided in patients who are candidates for pharmacologic reperfusion (e.g., with thrombolytic therapy).^{b 106 108}

Because peak drug concentrations are lower and circulation times are increased with peripheral vein administration compared with central venous injection, inject rapidly IV during resuscitative efforts and follow by a 20-mL flush of IV fluid.^{b 106}

If injected IV in an extremity, elevate the extremity for 10–20 seconds; when injected peripherally, 1–2 minutes generally are required for a drug to reach central circulation.^{b 106}

Rate of Administration

Preferably give IV rapidly because slow injection may cause a paradoxical slowing of the heart rate.^b

IV Infusion

Occasionally, infused IV† for the management of muscarinic poisoning (e.g., organophosphate pesticides).^l

Rate of Administration

Children: Has been infused IV† at a rate of 0.025 mg/kg per hour for muscarinic poisoning.^l

Adults: Has been infused IV† at an initial rate of 0.5–1 mg/hour for muscarinic poisoning, increasing as needed according to response and tolerance.^l

IM Injection

For self-medication, instruct patients and their caregivers carefully in proper administration techniques using the auto-injector provided by the manufacturer.¹⁰⁵

Inject the weight-appropriate dose IM only into the anterolateral aspect of the thigh.¹⁰⁵

In very thin patients and small children, bunch up the thigh prior to injection to provide a thicker injection area.¹⁰⁵

AtroPen 0.5, 1, or 2 mg: Grasp the prefilled auto-injector with the green tip pointed downward; the yellow activation (safety) cap should be removed.¹⁰⁵ Point the green tip toward the outer thigh, swing and jab it firmly into the outer thigh so that the auto-injector is perpendicular (90° angle) to the thigh, and hold firmly in the thigh for at least 10 seconds until the dose is delivered.¹⁰⁵

AtroPen 0.25 mg: Grasp the prefilled auto-injector with the black tip pointed downward; the grey activation (safety) cap should be removed.¹⁰⁵ Point the black tip toward the outer thigh and jab it firmly into the outer thigh so that the auto-injector is perpendicular (90° angle) to the thigh, and hold firmly in the thigh for at least 10 seconds until the dose is delivered.¹⁰⁵

Administer through clothing if necessary.¹⁰⁵

Massage injection area for several seconds.¹⁰⁵

If the needle is not exposed, check that the safety cap was removed and repeat administration but press harder.¹⁰⁵

Do not remove the activation cap until ready to use.¹⁰⁵

The auto-injector cannot be refilled nor can the exposed needle be retracted.¹⁰⁵

After use, bend the needle back against a hard surface and dispose of properly.¹⁰⁵

Endotracheal Administration

When IV or intraosseous† access cannot be established, may administer by the endotracheal route.¹⁰⁶

Dilution

Adults: Dilute dose in 5–10 mL of 0.9% sodium chloride injection or sterile water.¹⁰⁶

Intraosseous Administration

When IV administration is not possible, may be given by intraosseous† administration for CPR.¹⁰⁶

Oral Inhalation

Has been administered via oral inhalation using a nebulizer, but a solution for oral inhalation no longer is commercially available in the US.^b

Dilution

For administration via a nebulizer, the dose as a 0.2 or 0.5% solution has been diluted with 3–5 mL of 0.45 or 0.9% sodium chloride solution.^b

Dosage

Higher than recommended dosage sometimes has been required for therapeutic effect.^b Dosage should be titrated until therapeutic effect is achieved or adverse effects become intolerable (using the lowest possible effective dosage).^b

Pediatric Patients

Usual Dosage

Oral

Usual oral dosage is 0.01 mg/kg^f or 0.3 mg/m², but generally not exceeding 0.4 mg, every 4–6 hours.^b

IV, IM, or Sub-Q

Usual IV, IM, or sub-Q dose is 0.01 mg/kg^f or 0.3 mg/m², but generally not exceeding 0.4 mg^b ; if necessary, this dose may be repeated every 4–6 hours.^{b k}

Surgery

Preoperatively to Decrease Secretions and Block Cardiac Vagal Reflexes

IV, IM, or Sub-Q

Children weighing >20 kg: 0.4 mg given 30–60 minutes before anesthesia.^{PDH b} Higher doses (e.g., 0.5–0.6 mg) occasionally have been used in larger children (e.g., 32–41 kg).^{e j}

Children weighing <20 kg: 0.1 mg for 3 kg, 0.2 mg for 7–9 kg, or 0.3 mg for 12–16 kg given 30–60 minutes before anesthesia.^{PDH b}

Muscarinic Blockade during Anticholinesterase Reversal of Curariform Neuromuscular Blockade

Administer concurrently with (but in a separate syringe) or a few minutes before the anticholinesterase agent.^b

If bradycardia is present, administer before the anticholinesterase agent to increase pulse to about 80 bpm.^b

IV

Neonates and infants: 0.02-mg/kg dose of atropine sulfate concomitantly with each 0.04-mg/kg dose of neostigmine methylsulfate.^b

Children: 0.01- to 0.04-mg/kg dose of atropine sulfate concomitantly with each 0.025- to 0.08-mg/kg dose of neostigmine methylsulfate.^k

CPR and Cardiac Arrhythmias

Bradycardia and Pediatric Advanced Life Support

Current guidelines for ACLS no longer include recommendations for use in neonates.^{b 106} (See CPR and Cardiac Arrhythmias under Uses.)

Bradycardia may respond to adequate oxygenation and ventilation alone.¹⁰⁶

IV or Intraosseous†

Children and adolescents: 0.02 mg/kg, repeat once if needed; minimum pediatric dose is 0.1 mg and maximum single dose is 0.5 mg in children and 1 mg in adolescents.¹⁰⁶

Endotracheal

Children and adolescents: 0.03 mg/kg; repeat once if needed.¹⁰⁶

Follow each dose with a 5-mL flush of 0.9% sodium chloride injection; thereafter, apply 5 manual ventilations to promote absorption.¹⁰⁶

Pesticide Poisoning

Organophosphate Anticholinesterase Pesticides

Preferably should be administered IV, especially the initial dose.^b

A cholinesterase reactivator (pralidoxime) is administered concomitantly.^{b l m}

Some degree of atropinism should be maintained for at least 48 hours; prolonged therapy (e.g., for several weeks) may be necessary in severe cases.^{l m}

IV or IM

Children: 0.05 mg/kg IV (preferable) or IM up to an adult dose, repeated every 2–30 minutes until muscarinic signs and symptoms disappear.^{b l}

Alternatively, infuse IV† at a rate of 0.025 mg/kg per hour; continuous infusions have been maintained for up to several weeks in severe cases.^l

Adolescents: 1–2 mg IV (preferable) or IM, repeated every 2–60 minutes until muscarinic symptoms disappear.^{b e f l}

For severe cases, 2–6 mg may be given initially, repeating doses every 2–60 minutes.^{b e f l}

IM Self-administration

For self-administration using a prefilled auto-injector (e.g., AtroPen), dose is based on body weight and symptom severity.¹⁰⁵

Mild symptoms include miosis, blurred vision, tearing, runny nose, hypersalivation, drooling, wheezing, muscle fasciculations, nausea/vomiting.¹⁰⁵

Severe symptoms include behavioral changes, severe breathing difficulty, severe respiratory secretions, severe muscle twitching, involuntary defecation or urination, seizures, unconsciousness.¹⁰⁵

Children <7 kg: Inject 0.25 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 0.25-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children <7 kg who present with severe symptoms or are unconscious: Inject three 0.25-mg IM doses in rapid succession.¹⁰⁵

Children <7 kg: Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Children 7–18 kg: Inject 0.5 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 0.5-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children 7–18 kg who present with severe symptoms or are unconscious: Inject three 0.5-mg IM doses in rapid succession.¹⁰⁵

Children 7–18 kg: Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Children 18–41 kg: Inject 1 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 1-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children 18–41 kg who present with severe symptoms or are unconscious: Inject three 1-mg IM doses in rapid succession.¹⁰⁵

Children 18–41 kg: Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Children >41 kg: Inject 2 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 2-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children >41 kg who present with severe symptoms or are unconscious: Inject three 2-mg IM doses in rapid succession.¹⁰⁵

Children >41 kg: Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Carbamate Anticholinesterase Pesticides

Carbamate poisoning is treated with the same doses of atropine sulfate as for organophosphate poisoning and IM self-administration can be employed when necessary.^{105 l} (See Organophosphate Anticholinesterase Pesticides under Dosage.)

Concomitant cholinesterase reactivator (pralidoxime chloride) therapy may not be necessary and atropine therapy generally is less prolonged (e.g., only 1 or 2 days) and symptoms usually do not recur once asymptomatic.^l

Chemical Warfare Agent Poisoning

Organophosphate Anticholinesterase Nerve Agents

Administer IM in out-of-hospital setting or emergency department.^{101 105 b}

A cholinesterase reactivator (pralidoxime chloride) is administered concomitantly.^{b l m}

Give diazepam for seizure control.¹⁰¹

Total atropine sulfate doses usually are much less than those required for organophosphate anticholinesterase pesticide poisoning.^l

IM

Minimum dose in children is 0.1 mg.^l

Children 0–2 years of age with mild to moderate symptoms: Usual initial IM dose is 0.05 mg/kg.^{101 b}

Children 0–2 years of age with severe symptoms: Usual initial IM dose is 0.1 mg/kg.^{101 b}

Children 2–10 years of age with mild to moderate symptoms: Usual initial IM dose is 1 mg.^{101 b}

Children 2–10 years of age with severe symptoms: Usual initial IM dose is 2 mg.^{101 b}

Children older than 10 years of age with mild to moderate symptoms: Usual initial IM dose is 2 mg.^{101 b}

Children older than 10 years of age with severe symptoms: Usual initial IM dose is 4 mg.^{101 b}

Repeat doses every 2–10 minutes as needed until muscarinic toxicity resolves (e.g., secretions have diminished and breathing is comfortable or airway resistance has returned to near normal).^{101 b l}

IM Self-administration

For self-administration using a prefilled auto-injector (e.g., AtroPen), dose is based on body weight and symptom severity.¹⁰⁵

Mild symptoms include miosis, blurred vision, tearing, runny nose, hypersalivation, drooling, wheezing, muscle fasciculations, nausea/vomiting.¹⁰⁵

Severe symptoms include behavioral changes, severe breathing difficulty, severe respiratory secretions, severe muscle twitching, involuntary defecation or urination, seizures, unconsciousness.¹⁰⁵

Children <7 kg: Inject 0.25 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 0.25-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children <7 kg who present with severe symptoms or are unconscious: Inject three 0.25-mg IM doses in rapid succession.¹⁰⁵

Children <7 kg: Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Children 7–18 kg: Inject 0.5 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 0.5-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children 7–18 kg who present with severe symptoms or are unconscious: Inject three 0.5-mg IM doses in rapid succession.¹⁰⁵

Children 7–18 kg: Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Children 18–41 kg: Inject 1 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 1-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children 18–41 kg who present with severe symptoms or are unconscious: Inject three 1-mg IM doses in rapid succession.¹⁰⁵

Children 18–41 kg: Additional doses (i.e., >3) may be given every 5–10 minutes^l but only under the supervision of trained medical personnel.¹⁰⁵

Children >41 kg: Inject 2 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 2-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Children >41 kg who present with severe symptoms or are unconscious: Inject three 2-mg IM doses in rapid succession.¹⁰⁵

Children >41 kg: Additional doses (i.e., >3) may be given every 5–10 minutes^l but only under the supervision of trained medical personnel.¹⁰⁵

IV

Children 0–2 years of age with mild, moderate, or severe symptoms: May receive 0.02 mg/kg IV, if treated in an emergency department.^{101 b}

Mushroom Poisoning

Muscarine-containing Clitocybes and Inocybes

IV

If needed for severe symptoms, 0.02 mg/kg IV (minimum of 0.1 mg), repeated and titrated as needed according to response.^l

Bronchospasm

Treatment of Acute Exacerbations of Asthma

Oral Inhalation

Children: 0.05 mg/kg 3 or 4 times daily via nebulization;^b individual dose may be based on the patient’s weight as suggested in the following table, and may be adjusted according to the patient’s response and tolerance.^b

Weight	Pediatric Dose
15–25.8 kg	1 mg
25.9–37.6 kg	1.5 mg
37.7–63.2 kg	2.5 mg

Adults

Usual Dosage

Oral

Usual oral dosage is 0.4–0.6 mg (range: 0.1–1.2 mg) every 4–6 hours.^b

IV, IM, or Sub-Q

Usual IV, IM, or sub-Q dose is 0.4–0.6 mg (range: 0.3–1.2 mg); if necessary, this dose may be repeated every 4–6 hours.^b

Surgery

Preoperatively to Decrease Secretions and Block Cardiac Vagal Reflexes

IV, IM, or Sub-Q

0.4 mg (range: 0.2–1 mg) given 30–60 minutes before anesthesia.^{b e f}

Muscarinic Blockade during Anticholinesterase Reversal of Curariform Neuromuscular Blockade

IV

0.6–1.2 mg for each 0.5–2.5 mg of neostigmine methylsulfate or 10–20 mg of pyridostigmine bromide given.^b

Administer concurrently with (but in a separate syringe) or a few minutes before the anticholinesterase agent.

If bradycardia is present, administer before the anticholinesterase agent to increase pulse to 80 bpm.^b

CPR and Cardiac Arrhythmias

Selection of dosing interval (3–5 minutes) requires the clinician’s judgment about the severity of the patient’s symptoms; the shorter dosing intervals should be used in the more distressed patients (e.g., those with ventricular asystole).^{108 b f}

Endotracheal

Can administer via an endotracheal tube when atropine cannot be administered IV for bradycardia or ACLS during CPR.^{b 106 j}

Optimum dose for bradycardia and ACLS not established.¹⁰⁶ Doses 2–2.5 times usual IV doses have been recommended.^{b 106}

One manufacturer recommends a dose of 1–2 mg.^f

Intraosseous†

Can administer by intraosseous† infusion when atropine cannot be administered IV for ACLS during CPR.^{b 106}

Intraosseous doses usually have been the same as those administered IV, although some evidence suggests that intraosseous doses should be higher than those administered IV.^b

Asystole

IV

Usually, 1 mg; the dose may be repeated in 3–5 minutes if asystole persists up to a total of 3 doses (or up to 3 mg).¹⁰⁶

Slow Pulseless Electrical Activity

IV

Usually, 1 mg; the dose may be repeated in 3–5 minutes if necessary up to a total of 3 doses (or up to 3 mg).¹⁰⁶

Bradycardia

IV

0.5 mg; may repeat dose at 3- to 5-minute intervals up to a total dose of 3 mg.¹⁰⁶

Pesticide Poisoning

Organophosphate Anticholinesterase Pesticides

Preferably should be administered IV, especially the initial dose.^b

A cholinesterase reactivator (pralidoxime chloride) is administered concomitantly.^{b l m}

Some degree of atropinism should be maintained for at least 48 hours; prolonged therapy (e.g., for several weeks) may be necessary in severe cases.^{l m}

IV or IM

1–2 mg IV (preferable) or IM, repeated every 2–60 minutes until muscarinic symptoms disappear.^{b e f l} For severe cases, 2–6 mg may be given initially, repeating doses every 2–60 minutes.^{b e f l}

Alternatively, infuse IV at an initial rate of 0.5–1 mg/hour, adjusting rate according to response.^l

Mildly symptomatic poisoning may respond to 1–2 mg for reversal of muscarinic toxicity whereas moderate poisoning commonly requires total doses up to 40 mg.^l

For severe poisoning, 5-mg doses may be repeated every 2–3 minutes for stabilization.^l

Cumulative doses up to 1 g in 24 hours or 11 g over a course of treatment have been used.^l

IM Self-administration

For self-administration using a prefilled auto-injector (e.g., AtroPen), dose is based on body weight and symptom severity.¹⁰⁵

Mild symptoms include miosis, blurred vision, tearing, runny nose, hypersalivation, drooling, wheezing, muscle fasciculations, nausea/vomiting.¹⁰⁵

Severe symptoms include behavioral changes, severe breathing difficulty, severe respiratory secretions, severe muscle twitching, involuntary defecation or urination, seizures, unconsciousness.¹⁰⁵

Adults >41 kg: Inject 2 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 2-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Adults >41 kg who present with severe symptoms or are unconscious: Inject three 2-mg IM doses in rapid succession.¹⁰⁵

Additional doses (i.e., >3) should only be administered under the supervision of trained medical personnel.¹⁰⁵

Adults <41 kg: Pediatric doses can be used.¹⁰⁵ (See Pediatric Patients: Pesticide Poisoning, under Dosage.)

Oral

Oral therapy can replace parenteral therapy for maintenance as needed.^b

0.5–1 mg may be administered orally at intervals of several hours as maintenance therapy until signs and symptoms completely subside.^b

Carbamate Anticholinesterase Pesticides

Carbamate poisoning is treated with the same doses of atropine sulfate as for organophosphate poisoning and IM self-administration can be employed when necessary.^{105 l} (See Organophosphate Anticholinesterase Pesticides under Dosage.)

Concomitant cholinesterase reactivator (pralidoxime chloride) therapy may not be necessary and atropine therapy generally is less prolonged (e.g., only 1 or 2 days) and symptoms usually do not recur once asymptomatic.^l

Chemical Warfare Agent Poisoning

Organophosphate Anticholinesterase Nerve Agents

Administered IM in out-of-hospital setting or emergency department.^{101 105 b}

A cholinesterase reactivator (pralidoxime chloride) is administered concomitantly.^{b l m}

Give diazepam for seizure control.¹⁰¹

Total atropine sulfate doses usually are much less than those required for organophosphate anticholinesterase pesticide poisoning.^l

IM or IV

Mild to moderate symptoms: Usual initial IM dose is 2–4 mg.^{101 b l}

Severe symptoms: 5–6 mg.^{101 b l}

Frail geriatric patients with mild to moderate symptoms: 1 mg.^{101 b}

Frail geriatric patients with severe symptoms: 2–4 mg.^{101 b}

Repeat doses every 2–10 minutes as needed until muscarinic toxicity resolves (e.g., secretions have diminished and breathing is comfortable or airway resistance has returned to near normal).^{101 b l}

Up to 15–20 mg may be required within the first 3 hours,¹⁰⁴ but most patients respond to <20 mg usually during the initial 24 hours.^l In a report of sarin poisoning, <20% of moderately symptomatic patients required more than 2 mg.^l Pralidoxime chloride is administered concomitantly with atropine.¹⁰¹

IM Self-administration

For self-administration using a prefilled auto-injector (e.g., AtroPen), dose is based on body weight and symptom severity.¹⁰⁵

Mild symptoms include miosis, blurred vision, tearing, runny nose, hypersalivation, drooling, wheezing, muscle fasciculations, nausea/vomiting.¹⁰⁵

Severe symptoms include behavioral changes, severe breathing difficulty, severe respiratory secretions, severe muscle twitching, involuntary defecation or urination, seizures, unconsciousness.¹⁰⁵

Adults >41 kg: Inject 2 mg IM initially for mild symptoms.¹⁰⁵ If severe symptoms develop, inject 2 additional 2-mg IM doses in rapid succession 10 minutes after the initial dose.¹⁰⁵

Adults >41 kg who present with severe symptoms or are unconscious: Inject three 2-mg IM doses in rapid succession.¹⁰⁵

Additional doses (i.e., >3) may be given every 5–10 minutes^l but only under the supervision of trained medical personnel.¹⁰⁵

Adults <41 kg: Pediatric doses can be used.¹⁰⁵ (See Pediatric Patients: Pesticide Poisoning, under Dosage.)

Mushroom Poisoning

Muscarine-containing Clitocybes and Inocybes

IV

If needed for severe symptoms, 1–2 mg IV (minimum of 0.1 mg), repeated and titrated as needed according to response.^l

Radiographic Uses

Hypotonic Radiograph of the GI Tract

IM

1 mg IM.^{b e}

Bronchospasm

Treatment of Acute Exacerbations of Asthma

Oral Inhalation

0.025 mg/kg (usually up to 2.5 mg) 3 or 4 times daily via nebulization;^b individual dose may be based on the patient’s weight as suggested in the following table, and may be adjusted according to the patient’s response and tolerance.^b

Adult Weight	Adult Dose
30.5–50.8 kg	1 mg
50.9–75.8 kg	1.5 mg
75.9–126.4 kg	2.5 mg

Prescribing Limits

Pediatric Patients

CPR and Cardiac Arrhythmias

Bradycardia and Pediatric Advanced Life Support

IV or Intraosseous†

Children: Maximum single dose is 0.5 mg; maximum total dose is 1 mg.^{b 106}

Adolescents: Maximum single dose is 1 mg; maximum total dose is 2 mg.^{b 106}

Other Uses

Oral

Generally, not exceeding 0.4 mg.^b

IV

Generally, not exceeding 0.4 mg.^b

IM

Generally, not exceeding 0.4 mg.^b

Adults

CPR and Cardiac Arrhythmias

Asystole, Slow Pulseless Electrical Activity, and Bradycardia

IV

Total dose usually should not exceed 3 mg (0.04 mg/kg) in asystole, slow pulseless electrical activity, or bradycardia because complete vagal blockade (total vagolytic dose) generally occurs.^{b f 106}

Pesticide Poisoning

Organophosphate Anticholinesterase Pesticides

Maximum up to 1 g in 24 hours (with a cholinesterase activator [pralidoxime chloride]), depending on muscarinic severity.^l

Total cumulative doses up to 11 g (with a cholinesterase activator [pralidoxime chloride]) during a course of treatment, depending on muscarinic severity.^l

Chemical Warfare Agent Poisoning

Organophosphate Anticholinesterase Nerve Agents

IM or IV

Total atropine sulfate doses usually are much less than those required for organophosphate anticholinesterase pesticide poisoning.^l

Up to 15–20 mg may be required within the first 3 hours,¹⁰⁴ but most patients respond to <20 mg during the initial 24 hours.^l

Bronchospasm

Treatment of Acute Exacerbations of Asthma

Oral Inhalation

Usually, up to 2.5 mg per dose via nebulization;^b minimally increased efficacy but increased adverse effects with higher doses.^b

Special Populations

Hepatic Impairment

No specific hepatic dosage recommendations.^{105 e g}

Renal Impairment

No specific renal dosage recommendations.^{105 e g}

Geriatric Patients

Similar response between geriatric and younger patients.^f 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.^{101 f}

Cautions for Atropine

Contraindications

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  No absolute contraindications