Atropine (Systemic)

• Atropine Sulfate

• AtroPen

Antidote: Antidote for anticholinesterase poisoning (carbamate insecticides, nerve agents, organophosphate insecticides); antidote for muscarine-containing mushroom poisoning.

Adjuvant use with anticholinesterases (eg, edrophonium, neostigmine) to decrease their adverse effects during reversal of neuromuscular blockade.

Cardiovascular conditions: Treatment of symptomatic sinus bradycardia, atrioventricular (AV) nodal block.

Note: Likely not effective for type II second-degree or third-degree AV block (AHA [Hazinski 2015]). Use is no longer recommended in the management of asystole or pulseless electrical activity (PEA) (ACLS 2010).

Respiratory tract: Preoperative/preanesthetic medication to inhibit salivation and secretions.

Note: Doses <0.1 mg have been associated with paradoxical bradycardia.

Inhibit salivation and secretions (preanesthesia) (Nelson, 1996): Infants, Children, and Adolescents: IM, IV, SubQ: Administer dose 30 to 60 minutes preoperatively then every 4 to 6 hours as needed:

Infants <5 kg: 0.02 mg/kg/dose; use of a minimum dosage of 0.1 mg will result in dosages >0.02 mg/kg; there is no documented minimum dosage in this age group.

Infants and Children ≥5 kg: 0.01 to 0.02 mg/kg/dose; maximum single dose: 0.4 mg; minimum dose: 0.1 mg

Alternate dosing:

3 to 7 kg (7 to 16 lb): 0.1 mg

8 to 11 kg (17 to 24 lb): 0.15 mg

11 to 18 kg (24 to 40 lb): 0.2 mg

18 to 29 kg (40 to 65 lb): 0.3 mg

>30 kg (>65 lb): 0.4 mg

Bradycardia:

IV, I.O.: Infants, Children, and Adolescents: 0.02 mg/kg, minimum dose recommended by PALS: 0.1 mg; however, use of a minimum dosage of 0.1 mg in patients <5 kg will result in dosages >0.02 mg/kg and is not recommended (Barrington 2011); there is no documented minimum dosage in this age group; maximum single dose: 0.5 mg; may repeat once in 3 to 5 minutes; maximum total dose: 1 mg (PALS 2010).

Endotracheal (off-label route): Infants, Children, and Adolescents: 0.04 to 0.06 mg/kg; may repeat once if needed (PALS 2010)

Muscarine-containing mushroom poisoning (off-label dose): Infants, Children, and Adolescents: IV: 0.02 mg/kg/dose; minimum dose: 0.1 mg. Titrate and repeat as needed (Goldfrank 2015).

Organophosphate or carbamate insecticide or nerve agent poisoning: Infants, Children, and Adolescents: Note: The dose of atropine required varies considerably with the severity of poisoning. The total amount of atropine used for carbamate poisoning is usually less than with organophosphate insecticide or nerve agent poisoning. Severely poisoned patients may exhibit significant tolerance to atropine; ≥2 times the suggested doses may be needed. Titrate to pulmonary status (decreased bronchial secretions); consider administration of atropine via continuous IV infusion in patients requiring large doses of atropine. Once patient is stable for a period of time, the dose/dosing frequency may be decreased. Pralidoxime is a component of the management of organophosphate insecticide and nerve agent toxicity; refer to Pralidoxime monograph for the specific route and dose.

IV, IM (off-label dose): Initial: 0.05 to 0.1 mg/kg; repeat every 5 to 10 minutes as needed, doubling the dose if previous dose does not induce atropinization (Hegenbarth 2008; Rotenberg 2003). Maintain atropinization by administering repeat doses as needed for ≥2 to 12 hours based on recurrence of symptoms (Reigart, 1999).

IV infusion (off-label dose): Following atropinization, administer 10% to 20% of the total loading dose required to induce atropinization as a continuous IV infusion per hour; adjust as needed to maintain adequate atropinization without atropine toxicity (Eddleston 2004b; Roberts 2007).

IM (AtroPen):

Mild symptoms (≥2 mild symptoms): Administer the weight-based dose listed below as soon as an exposure is known or strongly suspected. If severe symptoms develop after the first dose, 2 additional doses should be repeated in rapid succession 10 minutes after the first dose; do not administer more than 3 doses. If profound anticholinergic effects occur in the absence of excessive bronchial secretions, further doses of atropine should be withheld.

Severe symptoms (≥1 severe symptoms): Immediately administer three weight-based doses in rapid succession.

Weight-based dosing:

<6.8 kg (15 lb): 0.25 mg/dose

6.8 to 18 kg (15 to 40 lb): 0.5 mg/dose

18 to 41 kg (40 to 90 lb): 1 mg/dose

>41 kg (>90 lb): 2 mg/dose

Symptoms of insecticide or nerve agent poisoning, as provided by manufacturer in the AtroPen product labeling, to guide therapy:

Mild symptoms: Blurred vision, bradycardia, breathing difficulties, chest tightness, coughing, drooling, miosis, muscular twitching, nausea, runny nose, salivation increased, stomach cramps, tachycardia, teary eyes, tremor, vomiting, or wheezing

Severe symptoms: Breathing difficulties (severe), confused/strange behavior, defecation (involuntary), muscular twitching/generalized weakness (severe), respiratory secretions (severe), seizure, unconsciousness, urination (involuntary); Note: Infants may become drowsy or unconscious with muscle floppiness as opposed to muscle twitching.

Endotracheal (off-label route): Increase the recommended dose by 2 to 3 times the usual IV dose. Mix with 3 to 5 mL of NS and administer. Flush with 3 to 5 mL of NS and follow with 5 assisted manual ventilations (Rotenberg 2003).

No dosage adjustment provided in manufacturer’s labeling.

IM: AtroPen: Administer to the outer thigh. Firmly grasp the autoinjector with the green tip (0.5 mg, 1 mg, and 2 mg autoinjector) or black tip (0.25 mg autoinjector) pointed down; remove the yellow safety release (0.5 mg, 1 mg, and 2 mg autoinjector) or gray safety release (0.25 autoinjector). Jab the green tip at a 90° angle against the outer thigh; may be administered through clothing as long as pockets at the injection site are empty. In thin patients or patients <6.8 kg (15 lb), bunch up the thigh prior to injection. Hold the autoinjector in place for 10 seconds following the injection; remove the autoinjector and massage the injection site. After administration, the needle will be visible; if the needle is not visible, repeat the above steps. After use, bend the needle against a hard surface (needle does not retract) to avoid accidental injury.

IV: Administer undiluted by rapid IV injection; slow injection may result in paradoxical bradycardia. In bradycardia, atropine administration should not delay treatment with external pacing.

Endotracheal: Dilute in NS or sterile water. Absorption may be greater with sterile water. Stop compressions (if using for cardiac arrest), spray the drug quickly down the tube. Follow immediately with several quick insufflations and continue chest compressions.

Store injection at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F); avoid freezing. In addition, AtroPen should be protected from light. Preparation of bulk atropine solution for mass chemical terrorism at a concentration of 1 mg/mL is stable for 72 hours at 4°C to 8°C (39°F to 46°F); 20°C to 25°C (68°F to 77°F); 32°C to 36°C (90°F to 97°F) (Dix 2003).

Frequency not always defined. Severity and frequency of adverse reactions are dose related.

Cardiovascular: Asystole, atrial arrhythmia, atrial fibrillation, atrioventricular dissociation (transient), bigeminy, bradycardia, chest pain, decreased blood pressure, ECG changes (prolonged P wave, shortened PR segment, R on T phenomenon, shortened RT duration, prolonged QT interval, widening of QRS Complex, flattened T wave, repolarization abnormalities, ST segment elevation, retrograde conduction), ectopic beats (atrial), extrasystoles (nodal, ventricular, superventricular), flushing, increased blood pressure, left heart failure, myocardial infarction, nodal arrhythmia (no P wave on ECG), palpitations, sinus tachycardia, supraventricular tachycardia (including junctional tachycardia), tachycardia, trigeminy, ventricular arrhythmia (including flutter), ventricular fibrillation, ventricular flutter, ventricular premature contractions, ventricular tachycardia, weak pulse (or impalpable peripheral pulses)

Central nervous system: Abnormal electroencephalogram (runs of alpha waves, increase in photic stimulation, and signs of drowsiness), agitation (children), amnesia, anxiety, ataxia, behavioral changes, coma, confusion, decreased deep tendon reflex, delirium, dizziness, drowsiness, dysarthria, dysmetria, emotional disturbance, excitement, feeling hot, hallucination (visual or aural), headache, hyperpyrexia, hyperreflexia, hypertonia, insomnia, intoxicated feeling, irritability (children), lack of concentration, lethargy (children), mania, myoclonus, neurologic abnormality, nocturnal enuresis, opisthotonus, paranoia, positive Babinski sign, restlessness, seizure (generally tonic-clonic), stupor, vertigo

Dermatologic: Anhidrosis, cold skin, dermatitis, dry and hot skin, erythematous rash, hyperhidrosis, macular eruption, maculopapular rash, papular rash, scarlatiniform rash, skin rash

Endocrine & metabolic: Dehydration, hyperglycemia, hypoglycemia, hypokalemia, hyponatremia, increased thirst, loss of libido

Gastrointestinal: Abdominal and bladder distension, abdominal pain, constipation, delayed gastric emptying, diminished bowel sounds, dry mucous membranes, dysphagia, malabsorption, nausea, oral lesion, paralytic ileus, salivation, vomiting, xerostomia

Genitourinary: Difficulty in micturition, impotence, urinary hesitancy, urinary retention, urinary urgency

Hematologic & oncologic: Abnormal erythrocytes (increased), decreased hemoglobin, increased hemoglobin, leukocytosis, petechiae

Hypersensitivity: Hypersensitivity reaction

Local: Injection site reaction

Neuromuscular & skeletal: Laryngospasm, muscle twitching, weakness

Ophthalmic: Abnormal eye movements (cyclophoria and heterophoria), angle-closure glaucoma (acute), blepharitis, blindness, blurred vision, conjunctivitis, crusted of eyelid, cycloplegia, decreased accommodation, decreased visual acuity, dry eye syndrome, eye irritation, keratoconjunctivitis sicca, lacrimation, mydriasis, photophobia, strabismus

Renal: Increased blood urea nitrogen

Respiratory: Bradypnea, changes in respiration (labored respiration), cyanosis, dyspnea, laryngitis, pulmonary edema, respiratory failure, stridor (inspiratory), tachypnea

Miscellaneous: Failure to thrive, fever (secondary to decreased sweat gland activity), swelling (children)