atropine sulfate

(a' troe peen)

Parenteral and oral preparations:

AtroPen, Minims (CAN), Sal-Tropine

Ophthalmic solution:

Atropine Sulfate S.O.P., Isopto Atropine Ophthalmic


Pregnancy Category C


Drug classes






Diagnostic agent (ophthalmic preparations)

Belladonna alkaloid


Therapeutic actions

Competitively blocks the effects of acetylcholine at muscarinic cholinergic receptors that mediate the effects of parasympathetic postganglionic impulses, depressing salivary and bronchial secretions, dilating the bronchi, inhibiting vagal influences on the heart, relaxing the GI and GU tracts, inhibiting gastric acid secretion (high doses), relaxing the pupil of the eye (mydriatic effect), and preventing accommodation for near vision (cycloplegic effect); also blocks the effects of acetylcholine in the CNS.



Systemic administration

        Antisialagogue for preanesthetic medication to prevent or reduce respiratory tract secretions

        Treatment of parkinsonism; relieves tremor and rigidity

        Restoration of cardiac rate and arterial pressure during anesthesia when vagal stimulation produced by intra-abdominal traction causes a decrease in pulse rate, lessening the degree of AV block when increased vagal tone is a factor (eg, some cases due to digitalis)

        Relief of bradycardia and syncope due to hyperactive carotid sinus reflex

        Relief of pylorospasm, hypertonicity of the small intestine, and hypermotility of the colon

        Relaxation of the spasm of biliary and ureteral colic and bronchospasm

        Relaxation of the tone of the detrusor muscle of the urinary bladder in the treatment of urinary tract disorders

        Control of crying and laughing episodes in patients with brain lesions

        Treatment of closed head injuries that cause acetylcholine release into CSF, EEG abnormalities, stupor, neurologic signs

        Relaxation of uterine hypertonicity

        Management of peptic ulcer

        Control of rhinorrhea of acute rhinitis or hay fever

        Antidote (with external cardiac massage) for CV collapse from overdose of parasympathomimetic (cholinergic) drugs (choline esters, pilocarpine), or cholinesterase inhibitors (eg, physostigmine, isoflurophate, organophosphorus insecticides)

        Antidote for poisoning by certain species of mushroom (eg, Amanita muscaria)

Ophthalmic preparations

        Diagnostically to produce mydriasis and cycloplegia-pupillary dilation in acute inflammatory conditions of the iris and uveal tract


Contraindications and cautions

        Contraindicated with hypersensitivity to anticholinergic drugs.

Systemic administration

        Contraindicated with glaucoma; adhesions between iris and lens; stenosing peptic ulcer; pyloroduodenal obstruction; paralytic ileus; intestinal atony; severe ulcerative colitis; toxic megacolon; symptomatic prostatic hypertrophy; bladder neck obstruction; bronchial asthma; COPD; cardiac arrhythmias; tachycardia; myocardial ischemia; impaired metabolic, liver, or kidney function; myasthenia gravis.

        Use cautiously with Down syndrome, brain damage, spasticity, hypertension, hyperthyroidism, lactation.

Ophthalmic solution

        Contraindicated with glaucoma or tendency to glaucoma.


Available forms

Tablets—0.4 mg; injection—0.05, 0.1, 0.3, 0.4, 0.5, 0.8, 1 mg/mL; ophthalmic ointment—1%; ophthalmic solution—0.5%, 1%, 2%; auto-injector—0.25, 0.5, 1, 2 mg




Systemic administration

        0.4–0.6 mg PO, IM, IV, or subcutaneously.

        Hypotonic radiography: 1 mg IM.

        Surgery: 0.5 mg (0.4–0.6 mg) IM (or subcutaneously or IV) prior to induction of anesthesia; during surgery, give IV; reduce dose to < 0.4 mg with cyclopropane anesthesia.

        Bradyarrhythmias: 0.4–1 mg (up to 2 mg) IV every 1–2 hr as needed.

        Antidote: For poisoning due to cholinesterase inhibitor insecticides, give large doses of at least 2–3 mg parenterally, and repeat until signs of atropine intoxication appear; for rapid type of mushroom poisoning, give in doses sufficient to control parasympathetic signs before coma and CV collapse intervene. Auto-injector provides rapid administration.

Ophthalmic solution

        For refraction: Instill 1–2 drops into eye(s) 1 hr before refracting.

        For uveitis: Instill 1–2 drops into eye(s) qid.


Systemic administration

Refer to the following table:


Dose (mg)

7–16 lb (3.2–7.3 kg)


16–24 lb (7.3–10.9 kg)


24–40 lb (10.9–18.1 kg)


40–65 lb (18.1–29.5 kg)


65–90 lb (29.5–40.8 kg)


> 90 lb (> 40.8 kg)


        Surgery: 0.1 mg (newborn) to 0.6 mg (12 yr) injected subcutaneously 30 min before surgery.

< 15 lb: 0.25 mg auto-injector.
15–40 lb: 0.5 mg auto-injector.
40–90 lb: 1 mg auto-injector.
> 90 lb: 2 mg auto-injector.


More likely to cause serious adverse reactions, especially CNS reactions, in elderly patients; use with caution.








10–15 min

30 min

4 hr



2–4 min

4 hr



1–2 hr

4 hr


5–10 min

30–40 min

7–14 days


Metabolism: Hepatic; T1/2: 2.5 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Urine


IV facts

Preparation: Give undiluted or dilute in 10 mL sterile water.

Infusion: Give direct IV; administer 1 mg or less over 1 min.


Adverse effects

Systemic administration

        CNS: Blurred vision, mydriasis, cycloplegia, photophobia, increased IOP, headache, flushing, nervousness, weakness, dizziness, insomnia, mental confusion or excitement (after even small doses in the elderly), nasal congestion

        CV: Palpitations, bradycardia (low doses), tachycardia (higher doses)

        GI: Dry mouth, altered taste perception, nausea, vomiting, dysphagia, heartburn, constipation, bloated feeling, paralytic ileus, gastroesophageal reflux

        GU: Urinary hesitancy and retention; impotence

        Other: Decreased sweating and predisposition to heat prostration, suppression of lactation

Ophthalmic preparations

        Local: Transient stinging

        Systemic: Systemic adverse effects, depending on amount absorbed



        Increased anticholinergic effects with other drugs that have anticholinergic activity—certain antihistamines, certain antiparkinsonian drugs, TCAs, MAOIs

        Decreased antipsychotic effectiveness of haloperidol with atropine

        Decreased effectiveness of phenothiazines, but increased incidence of paralytic ileus

        If cholinesterase inhibitors and atropine are given together, opposing effects will render both drugs ineffective


Nursing considerations


        History: Hypersensitivity to anticholinergic drugs; glaucoma; adhesions between iris and lens; stenosing peptic ulcer; pyloroduodenal obstruction; paralytic ileus; intestinal atony; severe ulcerative colitis; toxic megacolon; symptomatic prostatic hypertrophy; bladder neck obstruction; bronchial asthma; COPD; cardiac arrhythmias; myocardial ischemia; impaired metabolic, liver, or kidney function; myasthenia gravis; Down syndrome; brain damage; spasticity; hypertension; hyperthyroidism; lactation

        Physical: Skin color, lesions, texture; T; orientation, reflexes, bilateral grip strength; affect; ophthalmic exam; P, BP; R, adventitious sounds; bowel sounds, normal GI output; normal urinary output, prostate palpation; liver and kidney function tests, ECG



        Ensure adequate hydration; provide environmental control (temperature) to prevent hyperpyrexia.

        Have patient void before taking medication if urinary retention is a problem.


Teaching points

When used preoperatively or in other acute situations, incorporate teaching about the drug with teaching about the procedure; the ophthalmic solution is used mainly acutely and will not be self-administered by the patient; the following apply to oral medication for outpatients:

        Take as prescribed, 30 min before meals; avoid excessive dosage.

        Avoid hot environments; you will be heat intolerant, and dangerous reactions may occur.

        You may experience these side effects: Dizziness, confusion (use caution driving or performing hazardous tasks); constipation (ensure adequate fluid intake, proper diet); dry mouth (sugarless lozenges, frequent mouth care may help; may be transient); blurred vision, sensitivity to light (reversible; avoid tasks that require acute vision; wear sunglasses in bright light); impotence (reversible); difficulty in urination (empty the bladder prior to taking drug).

        Report rash; flushing; eye pain; difficulty breathing; tremors, loss of coordination; irregular heartbeat, palpitations; headache; abdominal distention; hallucinations; severe or persistent dry mouth; difficulty swallowing; difficulty in urination; constipation; sensitivity to light.


Adverse effects in Italic are most common; those in Bold are life-threatening.