Name: Atropine

Atropine Dosage

Atropine is given as an injection, taken orally, or administered in the eye with a dropper.

Your dose will depend on your medical condition.

Follow your doctor's instructions carefully when taking atropine. Don't take more or less of the drug than is prescribed.

If you're using the eye dropper, wash your hands before and after use.

If you're using the oral form of atropine, take it with a full glass of water.

Atropine Overdose

If you suspect an overdose, contact a poison control center or emergency room immediately.

You can get in touch with a poison control center at (800) 222-1222.

Missed Dose of Atropine

If you miss a dose of atropine, take it as soon as you remember.

However, if it's almost time for your next dose, skip the missed dose and continue on your regular dosing schedule.

Don't take extra medicine to make up for a missed dose.


Atropine Sulfate Ophthalmic Solution, USP 1% is a sterile topical anticholinergic for ophthalmic use. The active ingredient is represented by the chemical structure:

Chemical Name: Benzeneacetic acid, α-(hydroxymethyl)-, 8-methyl-8-azabicyclo[3.2.1.]oct-3-yl ester, endo –(±)-, sulfate (2:1) (salt), monohydrate.

Molecular Formula: (C17H23NO3) •H2SO4•H2O

Molecular Weight: 694.83 g/mol

Each mL of Atropine Sulfate Ophthalmic Solution USP, 1% contains: Active: atropine sulfate 10 mg equivalent to 8.3 mg of atropine. Inactives: benzalkonium chloride 0.1 mg (0.01%), dibasic sodium phosphate, edetate disodium, hypromellose (2910), monobasic sodium phosphate, hydrochloric acid and/or sodium hydroxide may be added to adjust pH (3.5 to 6. 0), and water for injection USP.

Uses of Atropine


Atropine is a prescription medication used to reduce salivation and bronchial secretions before surgery.

Atropine may also be used to restore cardiac rate and arterial pressure during anesthesia, to lessen the degree of atrioventricular heart block, to restore normal heart rate and rhythm, and as an antidote for the overdose or poisoning of a cholinergic drug.


Atropine is also used to dilate the pupil before eye exams and to relieve pain caused by swelling and inflammation in the eye.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Atropine Drug Class

Atropine is part of the drug class:

  • Opthalmic anticholinergics


Antimuscarinic; a naturally occurring tertiary amine.

Cautions for Atropine


  • No absolute contraindications to use in life-threatening conditions (e.g., poisoning by organophosphate nerve agents and pesticides).105 200

  • Relative contraindications include:

    • known hypersensitivity to atropine or any ingredient in the formulation105 b

    • angle-closure glaucoma105 b c

    • obstructive uropathy (e.g., bladder neck obstruction secondary to prostatic hypertrophy)c

    • obstructive GI disease (e.g., pyloroduodenal stenosis, achalasia)c

    • paralytic ileusc

    • intestinal atony (especially in geriatric and debilitated patients)c

    • severe ulcerative colitisc

    • toxic megacolonc

    • tachycardia secondary to cardiac insufficiency or thyrotoxicosis

    • acute hemorrhage when cardiovascular status is unstablec

    • myasthenia gravis (unless used to reduce adverse muscarinic effects of an anticholinesterase agent such as neostigmine)c




Avoid overdosage, especially with IV administration.198

Pediatric patients are particularly susceptible to overdosage.198

Pesticide and Chemical Warfare Agent Poisoning

Use in patients with a history of anaphylactic reaction to atropine and mildly symptomatic organophosphate pesticide or nerve agent poisoning only when there is adequate medical supervision.105

Severe breathing difficulty requires artificial respiration because atropine alone is not dependable in reversing respiratory muscle weakness or paralysis.105

Administer with extreme caution when the symptoms of nerve agent poisoning are less severe in patients with disorders of heart rhythm (e.g., atrial flutter), substantial renal insufficiency, or a recent MI.105

No more than 3 doses should be self-administered IM; additional doses require medical supervision.105

Sensitivity Reactions

Parabens present in multiple-dose preparations may cause hypersensitivity reactions.c

Hypersensitivity reactions may occasionally occur; usually skin rashes that may progress to exfoliation.105 200

Major Toxicities

Cardiovascular Effects

Caution in patients with cardiac disease.105 200 Because heart rate is a major determinant of myocardial oxygen requirements, excessive rate acceleration in patients with acute myocardial ischemia or infarction may worsen ischemia or increase extent of infarction.b

CNS Disturbances

Large or toxic doses or usual doses in patients with excess susceptibility may produce marked CNS disturbances (e.g., ranging from marked excitement, ataxia, hallucination, depression, and/or disorientation to active delirium to coma to death [secondary to respiratory failure]).105 200

Marked somnolence in susceptible patients.c

Mental confusion and/or excitement, especially in geriatric patients.c

GI Disturbances

Extreme caution in known or suspected GI infections because of decreased GI motility and retention of causative organism and/or toxins.c

Extreme caution in mild to moderate ulcerative colitis because of suppressed intestinal motility and resultant paralytic ileus and toxic megacolon.c

Extreme caution in diarrhea (especially in patients with ileostomy or colostomy) because it may be an early sign of intestinal obstruction.c

Caution in gastric ulcer because of delayed gastric emptying and possible antral stasis.c

Caution in esophageal reflux and hiatal hernia because of decreased gastric motility and lower esophageal sphincter pressure leading to gastric retention and reflux aggravation.c

GU Disturbances

Extreme caution in patients with partial obstructive uropathy because of decreased tone and amplitude of contractions of ureters and bladder and resultant urinary retention.c (See Contraindications under Cautions)

Respiratory Effects

Caution with systemically administered atropine in debilitated patients with chronic pulmonary disease because a reduction in bronchial secretions may lead to inspissation and formation of bronchial plugs; however, has been used effectively as bronchodilator when administered via oral inhalation.

Thermoregulatory Effects

Exposure to high environmental temperatures may result in heat prostration due to decreased sweating.c Increased risk of hyperthermia in patients who are febrile.c

General Precautions


Extreme caution in patients with autonomic neuropathy.c

Down’s Syndrome, Spastic Paralysis, and Brain Damage

Increased sensitivity to antimuscarinic effects (e.g., mydriasis, positive chronotropic effect).c


Caution in hypertensive patients.c


Caution in hyperthyroid patients.c

Seizure Management in Anticholinesterase Poisoning

Use barbiturates cautiously to manage seizures because the drugs are potentiated by anticholinesterases.105 Diazepam is preferred for seizure control.101

Specific Populations


Category C.105 c


Atropine is found in human milk in trace amounts; use caution when administered to a nursing woman.105

Pediatric Use

Safety and efficacy in the setting of organophosphate pesticide poisoning established in children of all ages.105

Increased susceptibility to the effects of atropine.105 c More susceptible than adults to toxic effects; deaths at doses as low as 10 mg.c

Infants, patients with Down’s syndrome (mongolism), and children with spastic paralysis or brain damage may be hypersensitive to antimuscarinic effects (e.g., mydriasis, positive chronotropic effect).c

Geriatric Use

Increased susceptibility to the effects of atropine.105 c Mental confusion and/or excitement are especially likely in geriatric patients.c

Hepatic Impairment

Use with caution in hepatic disease.c

Renal Impairment

Use with caution in renal disease.c

Common Adverse Effects

Most adverse effects are manifestations of pharmacologic effects at muscarinic-cholinergic receptors and usually are reversible when therapy is discontinued.c

Severity and frequency of adverse effects are dose related and individual intolerance varies greatly; adverse effects occasionally may be obviated by a reduction in dosage but this also may eliminate potential therapeutic effects.c

Frequent effects include xerostomia (dry mouth), dry skin, blurred vision, cycloplegia, mydriasis, photophobia, anhidrosis, urinary hesitancy and retention, tachycardia, palpitation, xerophthalmia, and constipation,105 200 c which may appear at therapeutic or subtherapeutic doses.c In many patients, xerostomia is the dose-limiting effect.c

Other common effects include increased ocular tension (especially in patients with angle-closure glaucoma), loss of taste, headache, nervousness, restlessness, drowsiness, weakness, dizziness, flushing, insomnia, nausea, vomiting, bloated feeling, anhidrosis (especially in hot environments),105 200 mild to moderate pain at the injection site,105 c loss of libido, and erectile dysfunction (via block of cholinergically mediated vasodilation).105 c

Interactions for Atropine

Drugs with Anticholinergic Effects

Additive adverse effects resulting from cholinergic blockade (e.g., xerostomia, blurred vision, constipation).c Advise of possibility of increased anticholinergic effects and monitor carefully.c

Effects on GI Absorption of Drugs

By inhibiting the motility of the GI tract and prolonging GI transit time, antimuscarinics have the potential to alter GI absorption of various drugs.c

Specific Drugs





Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Decreased GI absorption of atropinec

Administer oral atropine at least 1 hour before antacidsc

Anticholinergic drugs

Increased anticholinergic effectsc

Inform patient and monitor carefullyc

Antihistamines (anticholinergic)

Increased anticholinergic effectsc

Inform patient and monitor carefullyc

Antiparkinsonian (antimuscarinic) agents

Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Increased IOPc

Caution; monitor IOPc

Digoxin (slow dissolving)

Increased serum digoxinc

Use digoxin oral solution (elixir) or rapidly dissolving tablets (e.g., Lanoxin)c


Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Increased gastric pH decreases ketoconazole absorptionc

Administer atropine at least 2 hours after ketoconazolec


Increased GI metabolism of levodopa & decreased systemic concentrationsc

Adjust levodopa dosage if atropine is started or discontinuedc


Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Decreased GI absorption rate of mexiletine; no effect on bioavailability200

Muscle (anticholinergic) relaxants

Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Increased anticholinergic effectsc

Inform patient and monitor carefullyc

Potassium chloride

Slowed GI transit potentiates adverse GI effects of oral potassium chloride (especially wax-matrix tablets)c

Caution if used concomitantly; monitor for possible GI mucosal lesionsc


Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Increased rate of atropinizationc

Tricyclic antidepressants

Increased anticholinergic effectsc

Inform patient and monitor carefullyc


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.



Dosage Forms


Brand Names






equivalent to Atropine Sulfate 0.25 mg/0.3 mL

AtroPen Auto-Injector (“yellow label”)


equivalent to Atropine Sulfate 0.5 mg/0.7 mL

AtroPenAuto-Injector (“blue label”)


equivalent to Atropine Sulfate 1 mg/0.7 mL

AtroPenAuto-Injector (“dark red label”)


equivalent to Atropine Sulfate 2 mg/0.7 mL

AtroPenAuto-Injector (“green label”)


* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Atropine Sulfate


Dosage Forms


Brand Names






0.05 mg/mL*

Atropine Sulfate Injection

0.1 mg/mL*

Atropine Sulfate Injection

0.4 mg/mL*

Atropine Sulfate Injection

1 mg/mL*

Atropine Sulfate Injection

Commonly used brand name(s)

In the U.S.

  • AK-Dilate
  • AK-Pentolate
  • Altafrin
  • Atropine Care
  • Cyclogyl
  • Cyclomydril
  • Eye Cool
  • Homatropaire
  • Isopto Atropine
  • Isopto Homatropine
  • Isopto Hyoscine
  • Mydfrin
  • Mydral
  • Mydriacyl
  • Neofrin
  • Neo-Synephrine
  • Omidria
  • Paremyd

In Canada

  • Ak-Dilate
  • Ak-Pentolate
  • Atropine
  • Atropine-Ak
  • Atropine Eye Ointment
  • Atropine Ointment
  • Atropisol
  • Minims Phenylephrine Hydrochloride

Available Dosage Forms:

  • Ointment
  • Solution

Warnings and Precautions


When the recurrent use of Atropine is essential in patients with coronary artery disease, the total dose should be restricted to 2 to 3 mg (maximum 0.03 to 0.04 mg/kg) to avoid the detrimental effects of Atropine-induced tachycardia on myocardial oxygen demand.

Acute Glaucoma

Atropine may precipitate acute glaucoma.

Pyloric Obstruction

Atropine may convert partial organic pyloric stenosis into complete obstruction.

Complete Urinary Retention

Atropine may lead to complete urinary retention in patients with prostatic hypertrophy.

Viscid Plugs

Atropine may cause inspissation of bronchial secretions and formation of viscid plugs in patients with chronic lung disease.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

Studies have not been performed to evaluate the carcinogenic or mutagenic potential of Atropine or its potential to affect fertility adversely.

  • Alphagan-P
  • Azopt
  • Xalatan

© Atropine Patient Information is supplied by Cerner Multum, Inc. and Atropine Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.