Brand Name
AtroPen
Class and Category
Chemical class: Belladonna alkaloid
Therapeutic class: Anticholinergic, antimuscarinic
Pregnancy category: C
Indications and Dosages
To reduce respiratory tract secretions related to
anesthesia
TABLETS (ATROPINE SULFATE)
Adults. 0.4 to 0.6 mg preoperatively.
Children. 0.01 mg/kg up to total of 0.4 mg preoperatively
and repeated every 4 to 6 hr, p.r.n.
I.V.,I.M., OR SUBCUTANEOUS INJECTION
Adults. 0.4 to 0.6 mg preoperatively.
Children. 0.01 mg/kg up to total of 0.4 mg preoperatively
and repeated every 4 to 6 hr, p.r.n.
To correct bradycardia
I.V. INJECTION (ATROPINE SULFATE)
Adults. 0.4 to 1 mg. If no response to first dose,
repeat once after 5 min.
Children. 0.01 to 0.02 mg/kg with a minimum dose
of 0.1 mg and a maximum dose of 0.5 mg. If no response to first dose, repeat
once after 5 min.
To treat cholinesterase inhibitor (such as neostigmine,
pilocarpine, and methacholine) toxicity
I.V. INJECTION (ATROPINE SULFATE)
Adults. 2 to 4 mg. Then 2 mg every 5 to 10 min
until muscarinic signs (bradycardia, vasodilation, and pupil dilation)
disappear or signs of atropine intoxication develop.
I.V. OR I.M. INJECTION (ATROPINE
SULFATE)
Children. 1 mg. Then 0.5 to 1 mg every 5 to 10
min until muscarinic signs disappear or signs of atropine intoxication develop.
To treat mushroom (muscarine) toxicity
I.V. OR I.M. INJECTION (ATROPINE
SULFATE)
Adults. 1 to 2 mg every hr until respiratory signs
and symptoms subside.
To treat pesticide (organophosphate) toxicity
I.V. OR I.M. INJECTION (ATROPINE
SULFATE)
Adults. 1 to 2 mg, repeated in 20 to 30 min as
soon as cyanosis has cleared. Then continued until definite improvement is
maintained, possibly for 2 or more days.
To treat known or suspected exposure to chemical
nerve agent or insecticide
I.M. INJECTION (ATROPEN)
Adults and children weighing over 41 kg
(90 lb) with two or more mild symptoms.
2 mg. If severe symptoms develop
after injection, two or more 2-mg injections given in rapid
succession 10 min after initial injection.
Adults and children weighing over 41 kg
who are unconscious or have other severe symptoms. 2 mg given immediately 3 times in
rapid succession.
Children weighing 18 to 41 kg (40 to 90
lb) with two or more mild symptoms. 1 mg. If severe symptoms develop after injection, two
more 1-mg injections given in rapid succession 10 min after initial
injection.
Children weighing 18 to 41 kg who are unconscious
or exhibit any other severe symptoms. 1 mg given immediately 3 times in rapid succession.
Children weighing 7 to 18 kg (15 to 40
lb) with two or more mild symptoms. 0.5 mg. If severe symptoms develop after injection,
two more 0.5-mg injections given in rapid succession 10 min after
initial injection.
Children weighing 7 to 18 kg who are unconscious
or exhibit any other severe symptoms. 0.5 mg given immediately 3 times in rapid succession.
Mechanism of Action
Inhibits acetylcholine’s muscarinic action at the neuroeffector
junctions of smooth muscles, cardiac muscles, exocrine glands, SA and AV nodes,
and the urinary bladder. In small doses, atropine inhibits salivary and bronchial
secretions and diaphoresis. In moderate doses, it increases impulse conduction through
the AV node and increases heart rate. In large doses, it decreases GI and
urinary tract motility and gastric acid secretion.
Route Onset Peak Duration
P.O. 30–120 1–2 hr 4–6 hr min
I.V. Immediate 2–4 min Brief
I.M. 5–40 min 20–60 min Brief
SubQ Unknown Unknown Brief
Contraindications
Angle-closure glaucoma, asthma, GI obstructive disease
(achalasia, pyloric obstruction, pyloroduodenal stenosis), hepatic
disease, hypersensitivity to atropine or its components, ileus,
intestinal atony, myasthenia gravis, myocardial ischemia, obstructive
uropathy, renal disease, severe ulcerative colitis, tachycardia, toxic
megacolon, unstable cardiovascular status in acute hemorrhage
Interactions
DRUGS
adsorbent antidiarrheals, antacids: Decreased atropine absorption
amantadine, anticholinergics, antidyskinetics, glutethimide,
meperidine, muscle relaxants, phenothiazines, tricyclic antidepressants and other
drugs with anticholinergic properties, including antiarrhythmics (disopyramide,
procainamide, quinidine), antihistamines, buclizine, meclizine: Increased atropine effects antimyasthenics:
Reduced intestinal motility
cyclopropane: Risk of ventricular arrhythmias
haloperidol: Decreased antipsychotic effect
ketoconazole: Decreased ketoconazole absorption
metoclopramide: Decreased effect on GI motility
opioid analgesics: Increased risk of ileus, severe constipation, and
urine retention
potassium chloride, especially wax-matrix forms: Possibly GI ulcers
urinary alkalizers (calcium or magnesium antacids,
carbonic anhydrase inhibitors, citrates, sodium bicarbonate): Delayed excretion, increased risk of adverse
atropine effects
Adverse Reactions
CNS: Agitation, amnesia, anxiety, ataxia, Babinski’s or Chaddock’s reflex,
behavioral changes, CNS stimulation (at high doses), coma, confusion, decreased
concentration, decreased tendon reflexes, delirium, dizziness, drowsiness,
fever, hallucinations, headache, hyperreflexia, insomnia, lethargy, mania,
mental disorders, nervousness, paranoia, restlessness, seizures, somnolence,
stupor, syncope, vertigo, weakness
CV: Arrhythmias, bradycardia (at low doses), cardiac dilation, chest pain,
hypertension, hypotension, left ventricular failure, MI, palpitations,
tachycardia (at high doses), weak or impalpable peripheral pulses
EENT: Acute angle-closure glaucoma, altered taste, blepharitis, blindness,
blurred vision, conjunctivitis, cyclophoria, cycloplegia, decreased visual
acuity or accommodation, dry eyes or conjunctiva, dry mucous membranes, dry
mouth, eye irritation, eyelid crusting, heterophoria, increased intraocular
pressure, keratoconjunctivitis, lacrimation, laryngitis, laryngospasm, mydriasis,
nasal congestion, oral lesions, photophobia, pupils poorly reactive to light, strabismus,
tongue chewing
GI: Abdominal distention, abdominal pain, bloating, constipation, decreased
bowel sounds or food absorption, delayed gastric emptying, dysphagia,
heartburn, ileus, nausea, vomiting
GU: Bladder distention, enuresis, impotence, urinary hesitancy, urinary
urgency, urine retention
MS: Dysarthria, hypertonia, muscle twitching
RESP: Bradypnea, dyspnea, inspiratory stridor, pulmonary edema, respiratory
failure, shallow breathing, subcostal recession, tachypnea
SKIN: Cold skin, cyanosis, decreased sweating, dermatitis, flushing, rash,
urticaria
Other: Anaphylaxis, dehydration, injection site reaction, polydipsia,
sensations of warmth
Nursing Considerations
WARNING For patient prescribed AtroPen for
suspected nerve gas or insecticide exposure, dosage is determined by severity of
symptoms.
Mild symptoms include blurred vision, miosis, excessive
unexplained teary eyes or runny nose, increased salivation, chest tightness,
difficulty breathing, tremors, muscle twitching, nausea, vomiting, unexplained
wheezing or coughing, acute onset of stomach cramps, tachycardia, and
bradycardia.
Severe symptoms include confusion or other strange
behavior, severe difficulty breathing, extreme secretions from airway or lungs,
severe muscle twitching and general weakness, involuntary urination and defecation,
seizures, and unconsciousness.
• Avoid using high-dose atropine sulfate in patients with
ulcerative colitis because of risk of toxic megacolon or in patients with hiatal
hernia and reflux esophagitis because of risk of esophagitis
• AtroPen has no absolute contraindications when used to
treat life-threatening nerve gas or insecticide exposure.
WARNING Assess for symptoms of toxic doses of
atropine, such as excitement, agitation, drowsiness, and confusion, which are
likely to affect elderly patients even with low doses. If symptoms occur, take safety
precautions to prevent injury.
• Assess bowel and bladder elimination. Notify prescriber of
diarrhea, constipation, urinary hesitancy, or urine retention.
PATIENT TEACHING
• For patient prescribed an AtroPen to carry because of risk
of nerve gas or insecticide exposure, explain when and how to selfadminister the
drug.
• Instruct patient to take atropine sulfate 30 to 60 minutes
before meals.
• Advise patient to notify prescriber if he has persistent
or severe diarrhea, constipation, or difficulty urinating.
