Classifications: anticholinergic; antimuscarinic; antiarrhythmic;
Therapeutic: anticholinergic
; antimuscarinic; antiarrhythmic
Pregnancy Category: C


0.4 mg tablets; 0.05 mg/mL, 0.1 mg/mL, 0.3 mg/mL, 0.4 mg/mL, 0.5 mg/mL, 0.8 mg/mL, 1 mg/mL injection


Acts by selectively blocking all muscarinic responses to acetylcholine (ACh), whether excitatory or inhibitory. Antisecretory action (vagolytic effect) suppresses sweating, lacrimation, salivation, and secretions from nose, mouth, pharynx, and bronchi.

Therapeutic Effect

Potent bronchodilator when bronchoconstriction has been induced by parasympathomimetics, and decreases bronchial secretions. Decreases GI spasm. Produces mydriasis and cycloplegia by blocking responses of iris sphincter muscle and ciliary muscle of lens to cholinergic stimulation. Blocks vagal impulses to heart with resulting decrease in AV conduction time, increase in heart rate and cardiac output, and shortened PR interval.


Adjunct in symptomatic treatment of GI disorders (e.g., peptic ulcer, pylorospasm, GI hypermotility, irritable bowel syndrome) and spastic disorders of biliary tract. Relaxes upper GI tract and colon during hypotonic radiography. Ophthalmic Use: To produce mydriasis and cycloplegia before refraction and for treatment of anterior uveitis and iritis. Preoperative Use: To suppress salivation, perspiration, and respiratory tract secretions; to reduce incidence of laryngospasm, reflex bradycardia arrhythmia, and hypotension during general anesthesia. Cardiac Uses: For sinus bradycardia or asystole during CPR or that is induced by drugs or toxic substances (e.g., pilocarpine, beta-adrenergic blockers, organophosphate pesticides, and Amanita mushroom poisoning); for management of selected patients with symptomatic sinus bradycardia and associated hypotension and ventricular irritability; for diagnosis of sinus node dysfunction and in evaluation of coronary artery disease during atrial pacing; for management of chronic symptomatic sinus node dysfunction. Other Uses: Oral inhalation for short-term treatment and prevention of bronchospasms associated with asthma, bronchitis, and COPD and as drying agent in upper respiratory infection. Adjunctive therapy for hypermotility of GI tract.


Hypersensitivity to belladonna alkaloids; synechiae; angle-closure glaucoma; parotitis; obstructive uropathy (e.g., bladder neck obstruction caused by prostatic hypertrophy); intestinal atony, paralytic ileus, achalasia, pyloric stenosis, obstructive diseases of GI tract, severe ulcerative colitis, toxic megacolon; tachycardia secondary to cardiac insufficiency or thyrotoxicosis; acute hemorrhage; acute MI; myasthenia gravis; pregnancy (category C).

Cautious Use

Myocardial infarction, hypertension, hypotension; coronary artery disease, CHF, tachyarrhythmias; gastric ulcer, GI infections, hiatal hernia with reflux esophagitis; hyperthyroidism; COPD; autonomic neuropathy; hepatic or renal disease; older adults; debilitated patients; children <6 y of age; Down syndrome; autonomic neuropathy, spastic paralysis, brain damage in children; patients exposed to high environmental temperatures; patients with fever.

Route & Dosage

Adult: IV/IM/SC 0.4–0.6 mg 30–60 min before surgery
Child: IV/IM/SC <5 kg, 0.04 mg/kg; >5 kg, 0.03 mg/kg 30–60 min before surgery (max: 0.4 mg)

Adult: IV/IM 1 mg q2–3 min (max: 3 mg)
Child: IV/IM 0.01–0.03 mg/kg for 1–2 doses

Organophosphate Antidote
Adult: IV/IM 1–2 mg q5–60min until muscarinic signs and symptoms subside (may need up to 50 mg)
Child: IV/IM 0.05 mg/kg q10–30min until muscarinic signs and symptoms subside

Adult: Inhalation 0.025 mg/kg diluted with 3–5 mL saline, via nebulizer 3–4 times daily (max: 2.5 mg/d)
Child: Inhalation 0.03–0.05 mg/kg diluted with 3–5 mL saline, via nebulizer 3–4 times daily

Adult/Child: Ophthalmic 1–2 drops of solution or small amount of ointment in eye up to t.i.d.

Adult: Ophthalmic 1 drop of solution or small amount of ointment in eye 1 h before the procedure
Child: Ophthalmic 1–2 drops in eye b.i.d. for 1–3 d prior to procedure or a small amount of ointment in conjunctival sac t.i.d. for 1–3 d prior to procedure with last dose applied several hours before the procedure



PREPARE: Direct: Give undiluted or diluted in up to 10 mL of sterile water.  

ADMINISTER: Direct: Give 1 mg or fraction thereof over 1 min directly into a Y-site.  

INCOMPATIBILITIES Solution/additive: Pantoprazole.

  • Store at room temperature 15°–30° C (59°–86° F) in protected airtight, light-resistant containers unless otherwise directed by manufacturer.

Adverse Effects (≥1%)

CNS: Headache, ataxia, dizziness, excitement, irritability, convulsions, drowsiness, fatigue, weakness; mental depression, confusion, disorientation, hallucinations. CV: Hypertension or hypotension, ventricular tachycardia, palpitation, paradoxical bradycardia, AV dissociation, atrial or ventricular fibrillation. GI: Dry mouth with thirst, dysphagia, loss of taste; nausea, vomiting, constipation, delayed gastric emptying, antral stasis, paralytic ileus. Urogenital: Urinary hesitancy and retention, dysuria, impotence. Skin: Flushed, dry skin; anhidrosis, rash, urticaria, contact dermatitis, allergic conjunctivitis, fixed-drug eruption. Special Senses: Mydriasis, blurred vision, photophobia, increased intraocular pressure, cycloplegia, eye dryness, local redness.

Diagnostic Test Interference

Upper GI series: Findings may require qualification because of anticholinergic effects of atropine (reduced gastric motility and delayed gastric emptying). PSP excretion test: Atropine may decrease urinary excretion of PSP (phenolsulfonphthalein).


Drug: Amantadine, antihistamines, tricyclic antidepressants, quinidine, disopyramide, procainamide add to anticholinergic effects. Levodopa effects decreased. Methotrimeprazine may precipitate extrapyramidal effects. Antipsychotic effects of phenothiazines are decreased due to decreased absorption.


Absorption: Well absorbed from all administration sites. Peak effect: 30 min IM, 2–4 min IV, 1–2 h SC, 1.5–4 h inhalation, 30–40 min topical. Duration: Inhibition of salivation 4 h; mydriasis 7–14 d. Distribution: In most body tissues; crosses blood–brain barrier and placenta. Metabolism: In liver. Elimination: 77–94% in urine in 24 h. Half-Life: 2–3 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor vital signs. HR is a sensitive indicator of patient's response to atropine. Be alert to changes in quality, rate, and rhythm of HR and respiration and to changes in BP and temperature.
  • Initial paradoxical bradycardia following IV atropine usually lasts only 1–2 min; it most likely occurs when IV is administered slowly (more than 1 min) or when small doses (less than 0.5 mg) are used. Postural hypotension occurs when patient ambulates too soon after parenteral administration.
  • Note: Frequent and continued use of eye preparations, as well as overdosage, can have systemic effects. Some atropine deaths have resulted from systemic absorption following ocular administration in infants and children.
  • Monitor I&O, especially in older adults and patients who have had surgery (drug may contribute to urinary retention). Palpate lower abdomen for distention. Have patient void before giving atropine.
  • Monitor CNS status. Older adults and debilitated patients sometimes manifest drowsiness or CNS stimulation (excitement, agitation, confusion) with usual doses of drug or other belladonna alkaloids. In addition to dosage adjustment, side rails and supervision of ambulation may be indicated.
  • Monitor infants, small children, and older adults for "atropine fever" (hyperpyrexia due to suppression of perspiration and heat loss), which increases the risk of heatstroke.
  • Note: Intraocular tension and depth of anterior chamber should be determined before and during therapy with ophthalmic preparations to avoid glaucoma attacks (ophthalmic solutions and ointments are available in various strengths).
  • Patients receiving atropine via inhalation sometimes manifest mild CNS stimulation with doses in excess of 5 mg and mental depression and other mental disturbances with larger doses.

Patient & Family Education

  • Follow measures to relieve dry mouth: adequate hydration; small, frequent mouth rinses with tepid water; meticulous mouth and dental hygiene; gum chewing or sucking sugarless sourballs.
  • Note: Drug causes drowsiness, sensitivity to light, blurring of near vision, and temporarily impairs ability to judge distance. Avoid driving and other activities requiring visual acuity and mental alertness.
  • Discontinue ophthalmic preparations and notify physician if eye pain, conjunctivitis, palpitation, rapid pulse, or dizziness occurs.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2023 Last Updated On: 01/29/2023 (0)
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