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Drugs reference index «Atropine»



Pronunciation: (AT-troe-peen)Class: Belladonna alkaloid, Cycloplegic mydriatic

Trade Names:AtroPen- Injection 0.5 mg- Injection 1 mg- Injection 2 mg

Trade Names:Atropine Sulfate- Ophthalmic solution 1%- Injection 0.05 mg/mL- Injection 0.1 mg/mL- Injection 0.4 mg/mL- Injection 0.8 mg/mL- Injection 1 mg/mL

Trade Names:Atropine Sulfate Ophthalmic- Ointment 1%

Trade Names:Isopto Atropine- Ophthalmic solution 1%

Trade Names:Sal-Tropine- Tablets 0.4 mg

Atropine (Canada)Atropine Injection (Canada)Atropine Ointment (Canada)Minims Atropine (Canada)


Inhibits action of acetylcholine or other cholinergic stimuli at postganglionic cholinergic receptors, including smooth muscles, secretory glands, and CNS sites.



Rapidly absorbed after oral administration.


Readily crosses blood-brain barrier.


The t ½ is 3 h (IV). 94% of dose is eliminated through urine in 24 h.

Indications and Usage

Administration prior to anesthesia to reduce or prevent secretions of respiratory tract; to control rhinorrhea; treatment of parkinsonism; restoration of cardiac rate and arterial pressure in some situations; treatment of peptic ulcers; management of hypersecretion, irritation, or inflammation of stomach, intestines, or pancreas; treatment of diarrhea; relief of infant colic; management of spasms of bile tract; treatment of hypertonicity of small intestine and uterus; management of hypermotility of colon; prevention of spasm of pylorus, biliary tree, ureters, and bronchi; treatment of frequent urination and bed-wetting; therapy for certain bradycardias and heart blocks; treatment of closed head injury with acetylcholine release; reduction of laughing and crying associated with brain lesions; treatment of alcohol withdrawal symptoms; relief of motion sickness. Antidote for CV collapse in certain overdoses or poisonings (eg, organophosphorous nerve agents having cholinesterase activity, organophosphorous or carbamate insecticides, muscarinic symptoms of insecticide or nerve agent poisonings). Short-term treatment and prevention of bronchospasm associated with chronic bronchial asthma, bronchitis, and COPD.


Production of cycloplegia and mydriasis.


In the face of life-threatening poisonings by organophosphorous nerve agents and insecticides, there are no absolute contraindications for atropine use. Hypersensitivity to anticholinergics; narrow-angle glaucoma; primary glaucoma or tendency toward glaucoma (ophthalmic); adhesions between iris and lens; prostatic hypertrophy; obstructive uropathy; myocardial ischemia; unstable cardiac status caused by hemorrhage; tachycardia; myasthenia gravis; pyloric or intestinal obstruction; asthma; hyperthyroidism; renal disease; hepatic disease; toxic megacolon; intestinal atony or paralytic ileus.

Dosage and Administration


0.4 to 0.6 mg every 4 to 6 h.


PO Use lowest effective dose. The following doses may be exceeded in certain cases: 7 to 16 lb: 0.1 mg; 17 to 24 lb: 0.15 mg; 24 to 40 lb: 0.2 mg; 40 to 65 lb: 0.3 mg; 65 to 90 lb: 0.4 mg; over 90 lb: 0.4 mg.


Subcutaneous/IM/IV 0.4 to 0.6 mg every 4 to 6 h.


Subcutaneous/IM/IV 0.01 mg/kg to max of 0.4 mg every 4 to 6 h.

Infants less than 5 kg

Subcutaneous/IM/IV 0.04 mg/kg.

Infants over 5 kg

Subcutaneous/IM/IV 0.03 mg/kg.


Subcutaneous/IM/IV 0.4 to 2 mg every 1 to 2 h as needed.


Subcutaneous/IV/IM 0.01 to 0.03 mg/kg, every 1 to 2 h as needed.

Antidote (Insecticide Poisoning)Adults

Parenteral At least 2 to 3 mg, repeated until signs of poisoning subside or signs of intoxication appear.


0.02 to 0.05 mg/kg/dose every 10 to 20 min until signs of atropic effect are observed, then every 1 to 4 h for at least 24 h.


It is recommended that 3 AtroPen auto-injectors be available for use in each person at risk of nerve agent or organophosphate insecticide poisoning: 1 for mild symptoms plus 2 for severe symptoms as described in package insert.

Adults and Children weighing over 90 lb (41 kg) (generally older than 10 yr of age)

IM 2 mg.

Children weighing 40 to 90 lb (18 to 41 kg) (generally 4 to 10 yr of age)

IM 1 mg.

Children weighing 15 to 40 lb (7 to 18 kg) (generally 6 mo to 4 yr of age)

IM 0.5 mg.

Children weighing less than 15 lb (7 kg) (generally younger than 6 mo of age)

IM 0.25 mg.

OphthalmicUveitis Adults

1 to 2 drops 0.5% to 1% solution up to 4 times daily or ointment once or twice daily.


1 to 2 drops 0.5% solution 3 times daily.

Refraction Adults

1 to 2 drops of 1% solution 1 h before refraction examination.


1 to 2 drops 0.5% solution twice daily 1 to 3 days before refraction examination.

General Advice

  • Multiple concentrations are available for use. Carefully check concentration before administering medication to ensure that proper strength is being used.
  • Inspect injection solution before administration. Do not administer if solution is discolored, cloudy, or if particulate matter noted.
  • Use auto-injector as soon as symptoms of organophosphorous or carbamate poisoning (eg, tearing, excessive oral secretions, wheezing, muscle fasciculations) appear. Use additional auto-injectors as needed, but no more than 3 units unless under supervision of trained medical personnel, until atropinization (eg, flushing, mydriasis, tachycardia, dry mouth) is achieved.
  • Administer as IM injection into patient's mid-lateral thigh.



Store at temperature below 86°F.


Store at room temperature (less than 86°F). Protect from heat.


Store vials, prefilled syringes, and auto-injector at controlled room temperature (68° to 77°F). Protect from light and freezing.

Drug Interactions


Worsened schizophrenic symptoms; decreased serum haloperidol concentrations.

Other anticholinergic agents

Additive anticholinergic effects.


Decreased antipsychotic effects and increased anticholinergic effects may occur.

Laboratory Test Interactions

None well documented.

Adverse Reactions


Altered ST-T waves; systole; atrial arrhythmia; atrial ectopic beats; atrial fibrillation; bigeminal beats; bradycardia; cardiac dilation; cardiac syncope; decreased BP; flattening of T wave; increased BP; intermittent nodal rhythm (no P wave); labile BP; left ventricular failure; MI; nodal extrasystole; palpitations; prolongation of sinus node recovery time; prolonged P wave; prolonged QT interval; retrograde conduction; R on T phenomenon; shortened PR segment; shortened RT duration; supraventricular extrasystole; tachycardia (sinus, supraventricular, junctional); transient AV dissociation; trigeminal beats; ventricular arrhythmia; ventricular extrasystole; ventricular fibrillation; ventricular flutter; ventricular premature contractions; weak or impalpable pulses; widening and flattening of QRS complex.


Abnormal movements; agitation; amnesia; anxiety; ataxia; Babinski reflex/Chaddock reflex; behavioral changes; coma; confusion; delirium; depression; difficulty concentrating; diminished tendon reflex; dizziness; dysarthria; dysmetria; fatigue; hallucinations; headache; hyperreflexia; hypertonia; insomnia; lethargy; locomotor difficulties; loss of libido; mania; mental disorder; muscle clonus; muscle twitching; opisthotonos; paranoia; restlessness; seizures; sensation of intoxication; somnolence; stupor; tremor; vertigo; weakness; withdrawal behavior.


Cold skin; cyanosed skin; dermatitis; dry mucous membranes; dry warm skin; erythematous rash; flushing; macular rash; maculopapular rash; oral lesions; popular rash; petechiae rash; salivation; scarlatiniform rash; sweating/moist skin.


Acute angle-closure glaucoma; blepharitis; blindness; blurred vision; conjunctivitis; cyclophoria; cycloplegia; decreased accommodation; decreased contrast sensitivity; decreased visual acuity; dry conjunctiva; dry eyes; eyelid crusting; heterophoria; irritated eyes; keratoconjunctivitis; mydriasis; photophobia; pupils poorly reactive to light; sicca; strabismus; tearing.

Ophthalmic solution/ointment

Eczematoid dermatitis; follicular conjunctivitis; vascular congestion, edema, and exudates.


Abdominal distention; abdominal pain; constipation; decreased bowel sounds; decreased food absorption; delayed gastric emptying; distended abdomen; dry mouth; dysphagia; nausea; paralytic ileus; vomiting.


Bed wetting; difficulty in micturition; distended urinary bladder; impotency; urinary hesitancy or retention; urinary urgency.



Lab Tests

Alpha waves (EEG) blocked upon opening eyes; elevated BUN; elevated erythrocytes; elevated hemoglobin; hyperglycemia; hypoglycemia; hypokalemia; hyponatremia; increase in photic stimulation on EEG; leukocytosis; low hemoglobin; runs of alpha waves on EEG; signs of drowsiness on EEG.


Injection-site reaction.


Dehydration; failure to feed.


Breathing difficulty; inspiratory stridor; labored respirations; laryngospasm; pulmonary edema; respiratory failure; shallow respiration; slow respiration; subcostal recession; syncope; tachypnea.


Chest pain; excessive thirst; feeling hot; heat intolerance; hyperpyrexia; tongue chewing.



Baseline signs and symptoms

Identify baseline signs and symptoms, and monitor patients response to therapy according to indications for use: increased heart rate when used for bradycardia; decreased secretions for preanesthesia; decreased GI motility or decreased abdominal pain in GI disorders; pupil dilation in eye disorders; decreased tremor, rigidity and drooling in Parkinson disease. Notify health care provider if signs or symptoms do not improve or worsen.

Eyelid inflammation

Monitor patient's response to therapy. Notify health care provider if eye or eyelid inflammation is noted or if symptoms do not improve or worsen (ophthalmic).


Ensure that patient with moderate to severe poisoning is closely monitored for at least 48 h after emergency treatment has been provided (auto-injector).

Respiratory status

Monitor patients respiratory status. Be prepared to provide artificial respiration if severe breathing difficulty is noted (auto-injector).


Category C .


Excreted in breast milk. If possible, do not use.


Use cautiously in infants.

Special Risk Patients

Use with caution in the elderly, in patients with Down syndrome, brain damage, spastic paralysis, disorders of heart rhythm (eg, atrial flutter), severe narrow-angle glaucoma, pyloric stenosis, prostatic hypertrophy, significant renal failure, or a recent MI.

Anticholinergic psychosis

Has occurred in sensitive patients.


May be an early symptom of incomplete intestinal obstruction.

Gastric ulcer

May delay gastric emptying time and complicate therapy.


Determine IOP and depth of angle of anterior chamber before and during ophthalmic use to avoid glaucoma attacks.

Heat prostration

May occur at high ambient temperature.



Dry mouth, thirst, vomiting, nausea, abdominal distention, CNS stimulation, delirium, drowsiness, restlessness, stupor, fever, seizures, hallucinations, convulsions, coma, circulatory failure, tachycardia, weak pulse, hypertension, hypotension, respiratory depression, palpitations, urinary urgency, blurred vision, dilated pupils, photophobia, rash, dry and hot skin.

Patient Information

  • Oral
  • Advise patient using atropine for GI problems to take prescribed dose 30 to 60 min before meals and at bedtime.
  • Advise patient using atropine for other conditions to take as prescribed without regard to meals, but to take with food if stomach upset occurs.
  • Advise patient that dose and/or frequency of use may be changed periodically to achieve max benefit.
  • Caution patient not to change the dose or stop taking unless advised by health care provider. Advise patient to notify health care provider if symptoms do not improve, appear to worsen, or if bothersome side effects occur.
  • Instruct patient to stop taking the drug and notify health care provider immediately if any of the following occur: rash, flushing, eye pain, inability to urinate, confusion, disorientation, hallucinations, change in behavior.
  • Advise patient to avoid strenuous activity during periods of high temperature or humidity.
  • Advise patient to take sips of water, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
  • Inform patient that medication may cause pupils to dilate, resulting in intolerance to bright lights or sunlight. Advise patient to wear dark glasses to make bright lights or sunlight tolerable.
  • Advise patient that drug may cause drowsiness, dizziness, or blurred vision, and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Ophthalmic
  • Remind patient or caregiver that solution and ointment are for use in the eye only.
  • Teach patient or caregiver proper technique for instilling ophthalmic solution or ointment: wash hands; do not allow tip of dropper bottle or tube to touch eye, eyelid, fingers or any other surface. Tilt head back, look up; pull lower eyelid down to form pocket; place prescribed number of drops or amount of ointment in the pocket; look downward before closing eye; compress lacrimal sac for 2 to 3 min after instillation complete. Caution patient not to rub eye(s).
  • Advise patient or caregiver that if more than 1 topical ophthalmic drug is being used, instill eye drops first, wait at least 5 min, and then instill ointment last.
  • Caution patient that blurred vision may occur and not to drive or engage in hazardous activities while pupil(s) are dilated.
  • Advise patient or caregiver to contact health care provider if eye drops or ointment cause intolerable stinging, if eye or eyelid inflammation is noted, or if eye symptoms do not improve or worsen.
  • Injection
  • Advise patient that medication, with exception of auto-injector, will be prepared and administered by a health care provider in a medical setting.
  • Review the patient information leaflet and instruction guide with potential user of auto-injector. Ensure that potential user of the auto-injector understands the indications for and use of the auto-injector, including symptoms of poisoning and preparation and use of the auto-injector.
  • Emphasize to potential user of auto-injector that medical attention must be sought immediately after use of the auto-injector.
  • Caution potential user of auto-injector that the primary protection against exposure to chemical nerve agents and insecticide poisonings is the wearing of protective garments, including masks designed specifically for protection.

Copyright © 2009 Wolters Kluwer Health.

  • Atropine Prescribing Information (FDA)
  • Atropine Advanced Consumer (Micromedex) - Includes Dosage Information
  • Atropine MedFacts Consumer Leaflet (Wolters Kluwer)
  • atropine Concise Consumer Information (Cerner Multum)
  • Atreza MedFacts Consumer Leaflet (Wolters Kluwer)
  • AtroPen Prescribing Information (FDA)

See Also...

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