Dosing & Uses
Dosage Forms & Strengths
intramuscular device
- 0.25mg/0.3mL
- 0.5mg/0.7mL
- 1mg/0.7mL
- 2mg/0.7mL
injectable solution
- 0.05mg/mL
- 0.1mg/mL
- 0.4mg/mL
- 0.8mg/mL
- 1mg/mL
Anesthesia Premedication
0.4-0.6 mg IV/IM/SC 30-60 minutes before anesthesia; repeat q4-6hr PRN
Sinus Bradycardia (ACLS)
0.5-1 mg or 0.04 mg/kg IV q5min, no more than 3 mg
ET: Some experts suggest 2-3 times IV dose diluted in3- 5 mL sterile water for injection/NS (sterile water for injection may facilitate absorption better than NS, but may produce more negative effect on arterial oxygen pressure)
Bronchospasm
0.025 mg/kg in 2.5 mL NS q6-8hr via nebulizer; no more than 2.5 mg/dose
Organophosphate or Carbamate (Cholinesterase Inhibitors) Poisoning
Symptoms of organophosphate and/or carbamate poisoning
-
Mild symptoms
- Blurred vision or miosis
- Unexplained excessive lacrimation
- Unexplained excessive nasopharyngeal secretions
- Increased salivation
- Chest tightness, difficulty breathing, wheezing, or coughing
- Tremors throughout the body or muscular twitching
- Nausea, vomiting, abdominal cramping, or diarrhea
- Tachycardia or bradycardia
-
Severe symptoms
- Altered mental status
- Loss of consciousness
- Respiratory distress
- Excessive secretions from the lungs/airway
- Severe muscular twitching, generalized weakness or paralysis
- Involuntary urination and/or defecation
- Convulsions or seizures
IM Autoinjector
Two or more mild symptoms of nerve agent (nerve gas) or insecticide exposure: Administer 1 injection (2 mg) IM
Wait 10-15 minutes for drug to take effect; if, after 10-15 minutes, patient does not develop any severe symptoms, no additional injections recommended
If after first dose, patient develops severe symptoms, administer 2 additional injections IM in rapid succession
If possible, a person other than patient should administer second and third 2 mg autoinjector
If patient is either unconscious or has any severe symptoms, immediately administer 3 injections intramuscularly into patient’s mid-lateral outer thigh in rapid succession
Antidotes should not be relied upon solely to provide complete protection from chemical nerve agents and insecticide poisoning
Dosage Forms & Strengths
intramuscular device
- 0.25mg/0.3mL
- 0.5mg/0.7mL
- 1mg/0.7mL
- 2mg/0.7mL
injectable solution
- 0.05mg/mL
- 0.1mg/mL
- 0.4mg/mL
- 0.8mg/mL
- 1mg/mL
Anesthesia Premedication
<5 kg: 0.02 mg/kg/dose 30-60 minutes preop; then q4-6hr PRN
>5 kg: 0.01-0.02 mg/kg IV/IM/SC; no more than 0.4 mg
Sinus Bradycardia
0.02 mg/kg IV/IO q5min for 2-3 doses PRN; single dose no less than: 0.1 no more than 0.5 mg (children), 1 mg (adolescents)
Total: No more than: 1 mg (children), 2 mg (adolescents)
ET: Some experts suggest 0.03 mg/kg, diluted in NS
Bronchospasm
0.025-0.05 mg/kg in 2.5 mL NS q6-8hr via nebulizer; no more than 2.5 mg/dose
Organophosphate or Carbamate (Cholinesterase Inhibitors) Poisoning
Symptoms of organophosphate and/or carbamate poisoning
-
Mild symptoms
- Blurred vision or miosis
- Unexplained excessive lacrimation
- Unexplained excessive nasopharyngeal secretions
- Increased salivation
- Chest tightness, difficulty breathing, wheezing, or coughing
- Tremors throughout the body or muscular twitching
- Nausea, vomiting, abdominal cramping, or diarrhea
- Tachycardia or bradycardia
-
Severe symptoms
- Altered mental status Loss of consciousness
- Respiratory distress
- Excessive secretions from the lungs/airway
- Severe muscular twitching, generalized weakness or paralysis
- Involuntary urination and/or defecation
- Convulsions or seizures
IV: 0.03-0.05 mg/kg IV/IM/IO/ET q10-20min PRN to effect; then q1-4hr for at least 24 hours
IM Autoinjector
Two or more mild symptoms of nerve agent (nerve gas) or insecticide exposure: Administer one 1 injection (2 mg) IM
Wait 10-15 minutes for drug to take effect; if, after 10-15 minutes, patient does not develop any severe symptoms, no additional injections recommended
If after first dose, patient develops severe symptoms, administer 2 additional injections IM in rapid succession
If possible, a person other than patient should administer second and third 2 mg autoinjector
If patient is either unconscious or has any severe symptoms, immediately administer 3 injections intramuscularly into patient’s mid-lateral outer thigh in rapid succession
Antidotes should not be relied upon solely to provide complete protection from chemical nerve agents and insecticide poisoning
See specific dose for weight below
Severe symptoms
- 3 AtroPen doses in rapid succession
- >41 kg: 2 mg/dose IM
- 18-41 kg: 1 mg/dose IM
- 6.8-18 kg: 0.5 mg/dose IM
- <6.8 kg: AtroPen formulation not recommended; administer atropine 0.05 mg/kg bradyarrhythmias
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
Frequency Not Defined
Anticholinergic symptoms (mydriasis, hyperthermia, tachycardia, cardiac arrhythmia, delayed gastric emptying)
Ataxia
Fever
Headache
Insomnia
Dry mouth
Anhidrosis
Urticaria
Urinary hesitancy
Dry skin
Blurred vision
Cycloplegia
Photophobia
Anhidrosis
Palpitation
Dyspnea
Paralytic ileus
Pulmonary edema
Nasal dryness
Xerophthalmia
Constipation
May increase IOP in predisposed patients
May cause CNS disturbances (especially in pediatric patients)
Warnings
Contraindications
No absolute contraindications for ACLS
- Ineffective in hypothermic bradycardia
Narrow-angle glaucoma, tachycardia, asthma, GI obstruction, severe ulcerative colitis, toxic megacolon, bladder outlet obstruction
Cautions
Caution in hepatic/renal impairment, BPH, CHF
Not for effective treatment of type II second or third-degree AV block with or without a new wide QRS complex
Use caution in autonomic neuropathy, myocardial ischemia, heart failure, paralytic ileus, hepatic impairment, hiatal hernia associated with reflux esophagitis, hyperthyroidism, myasthenia gravis, and renal impairment
May inhibit sweating which, in a warm environment or with excessive exercise, can lead to hyperthermia and heat injury; to the extent feasible, avoid excessive exercise and heat exposure
Psychosis reported in sensitive individuals and with excessive doses
When recurrent use of atropine is essential in patients with coronary artery disease, total dose should be restricted to 2 to 3 mg (maximum 0.03 to 0.04 mg/kg) to avoid detrimental effects of atropine-induced tachycardia on myocardial oxygen demand
May cause acute glaucoma; administer with caution in patients at risk for acute glaucoma or who have severe narrow angle glaucoma; monitor for signs and symptoms of intraocular pressure, as appropriate
May convert partial organic pyloric stenosis into complete obstruction; patients should be monitored for gastrointestinal symptoms following administration of
May cause urinary retention; administer with caution to patients with clinically significant bladder outflow obstruction
May cause thickening of bronchial secretions and formation of dangerous viscid plugs in individuals with chronic lung disease; respiratory status should be monitored in individuals with chronic lung disease following administration of therapy
Drug can cause hypersensitivity reactions, including anaphylactic reactions; medical supervision necessary in patients who have had previous anaphylactic reactions to drug and require treatment for organophosphorus or nerve agent poisoning
Cardiovascular risks
- Cardiovascular adverse reactions reported include, but are not limited to, sinus tachycardia, palpitations, premature ventricular contractions, atrial flutter, atrial fibrillation, ventricular flutter, ventricular fibrillation, cardiac syncope, asystole, and myocardial infarction
- In patients with a recent myocardial infarction and/or severe coronary artery disease, there is possibility that atropine-induced tachycardia may cause ischemia, extend or initiate myocardial infarcts, and stimulate ventricular ectopy and fibrillation
- Use with caution in patients with known cardiovascular disease or cardiac conduction problems
Pregnancy & Lactation
Pregnancy
Drug readily crosses the placental barrier and enters fetal circulation; there are no adequate data on developmental risk associated with use of atropine in pregnant women; adequate animal reproduction studies have not been conducted with atropine
Lactation
Drug reported to be excreted in human milk; there are no data on effects of atropine on breastfed infant or effects on milk production; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from therapy or from underlying maternal condition
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Competitively inhibits action of ACh on autonomic effectors innervated by postganglionic nerves; reverses muscarinic effects of cholinergic poisoning caused by agents with cholinesterase inhibitor activity by acting as a competitive antagonist of acetylcholine ast muscarinic receptors; blocks action of acetylcholiine at parsympathetic sites in secretory glands, and CNS; inhibits salivation, tracheobronchial secretions, bradycardia, hypotension
Antimuscarinic agent
Pharmacokinetics
Half-life: 2-3 hr (>2 years and adults); 7 hr (<2 years); 10 hr (65-75 years)
Peak plasma time: 3 min (IM)
Onset: Rapid (IV/IM)
Bronchodilation: Within 15 min; max within 15 min-1.5 hr (oral inhalation)
Distribution: Throughout the body; crosses blood brain barrier
Absorption: Principally from the upper small intestine
Metabolites: Tropic acid, tropine, and possibly esters of tropic acid and glucuronide conjugates
Metabolism: Liver via enzymatic hydrolysis
Excretion: Urine (30-50%); small amounts may also be eliminated in expired air as carbon dioxide and in feces
Administration
IV Incompatibilities
Additive: floxacillin
Syringe: cimetidine with pentobarbital
Y-site: thiopental
Not spec: ampicillin, diazepam, epinephrine, norepinephrine
IV Compatibilities
Additive: dobutamine, furosemide, meropenem, netilmicin, Na bicarb, verapamil
Syringe: (partial list) cimetidine, fentanyl, glycopyrrolate, heparin, hydroxyzine, meperidine, morphine, pentobarbital
Y-site: abciximab, amiodarone, argatroban, etomidate, famotidine, fenoldopam, fentanyl, heparin, hydrocortisone, hydromorphone, inamrinone, meropenem, methadone, morphine, nafcillin, KCl, propofol, sufentanil, tirofiban, vit B/C
IV Administration
Give into large vein or IV tubing over 1-2 min
Autoinjector
Should have available three (3) autoinjectors, one for mild symptoms plus 2 for severe symptoms, for use in each patient at risk for nerve agent or organophosphate insecticide poisoning
Only administer to patients experiencing symptoms of organophosphorus poisoning in a situation where exposure is known or suspected
The autoinjector is intended as an initial treatment of muscarinic symptoms of insecticide or nerve agent poisonings as soon as symptoms appear; definitive medical care should be sought immediately
Not to be administered until cyanosis has been overcome; atropine may produce ventricular fibrillation and possible seizures in presence of hypoxia
To be used by persons who have had adequate training in recognition and treatment of nerve agent or insecticide intoxication; may be administered by a caregiver or by self-administration if a trained provider is not available
Close supervision of all treated patients indicated for at least 48 to 72 hours
In severe poisonings, concurrent administration of an anticonvulsant (preferably a benzodiazepine) may be warranted if seizure is suspected in the unconscious individual because overt jerking may not be apparent because of the effects of the poison
In poisonings caused by organophosphorous nerve agents and insecticides it may also be helpful to concurrently administer a cholinesterase reactivator such as pralidoxime chloride
The injection site is the mid-lateral thigh area; the autoinjector can inject through clothing; however, make sure pockets at the injection site are empty; people who may not have a lot of fat at injection site should also be injected in mid-lateral outer thigh; before giving the injection, bunch up the thigh to provide a thicker area for injection.
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Formulary
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