atropine

Inhibits the action of acetylcholine at postganglionic sites located in:
- Smooth muscle,
- Secretory glands,
- CNS (antimuscarinic activity).
Low doses decrease:
- Sweating,
- Salivation,
- Respiratory secretions.
Intermediate doses result in:
- Mydriasis (pupillary dilation),
- Cycloplegia (loss of visual accommodation),
- Increased heart rate.
GI and GU tract motility are decreased at larger doses.

Therapeutic effects:

Increased heart rate.
Decreased GI and respiratory secretions.
Reversal of muscarinic effects.
May have a spasmolytic action on the biliary and genitourinary tracts.

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed following SUBQ administration. IV administration results in complete bioavailability.

Distribution: Readily crosses the blood-brain barrier. Crosses the placenta and enters breast milk.

Metabolism/Excretion: Mostly metabolized by the liver; 30–50% excreted unchanged by the kidneys.

Half-Life: Children <2 yr: 4–10 hr; Children >2 yr: 1.5–3.5 hr; Adults: 4–5 hr.

Time/Action Profile ⬆ ⬇

(inhibition of salivation)

ROUTE	ONSET	PEAK	DURATION
SUBQ	rapid	15–50 min	4–6 hr
IV	immediate	2–4 min	4–6 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Angle-closure glaucoma;
Acute hemorrhage;
Tachycardia secondary to cardiac insufficiency or thyrotoxicosis;
Obstructive disease of the GI tract.

Use Cautiously in:

Intra-abdominal infections;
Prostatic hyperplasia;
Chronic renal, hepatic, pulmonary, or cardiac disease;
OB: Safety not established in pregnancy;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Infants with Down syndrome have ↑ sensitivity to cardiac effects and mydriasis. Children may have ↑ susceptibility to adverse reactions. Exercise care when prescribing to children with spastic paralysis or brain damage;
Geri: Appears on Beers list. ↑ risk of adverse reactions in older adults due to anticholinergic effects. Avoid use of all formulations in older adults except for ophthalmic formulations.

Adv. Reactions/Side Effects ⬆ ⬇

CV: tachycardia, arrhythmias, palpitations

Derm: ↓sweating, flushing

EENT: blurred vision, cycloplegia, dry eyes, mydriasis, photophobia

GI: dry mouth, constipation, impaired GI motility

GU: urinary hesitancy, impotency, retention

Neuro: drowsiness, confusion

Resp: pulmonary edema, tachypnea

Interactions ⬆ ⬇

Drug-drug:

↑anticholinergic effects with other anticholinergics, including antihistamines, tricyclic antidepressants, quinidine, and disopyramide.
Anticholinergics may alter the absorption of other orally administered drugs by slowing motility of the GI tract.
Antacids↓ absorption of anticholinergics.
May ↑ GI mucosal lesions in patients taking oral potassium chloride tablets.
May alter response to beta-blockers.

Route/Dosage ⬆ ⬇

Preanesthesia (To Decrease Salivation/Secretions)

IV SC (Adults ): 0.4–0.6 mg 30–60 min preop.
IV SC (Children >5 kg): 0.01–0.02 mg/kg/dose 30–60 min preop to a maximum of 0.4 mg/dose; minimum: 0.1 mg/dose.
IV SC (Children <5 kg): 0.02 mg/kg/dose 30–60 min preop then every 4–6 hr as needed.

Bradycardia

IV (Adults ): 0.5–1 mg; may repeat as needed every 5 min, not to exceed a total of 2 mg (every 3–5 min in Advanced Cardiac Life Support guidelines) or 0.04 mg/kg (total vagolytic dose).
IV (Children ): 0.02 mg/kg (maximum single dose is 0.5 mg in children and 1 mg in adolescents); may repeat every 5 min up to a total dose of 1 mg in children (2 mg in adolescents).
Endotracheal(Children ): use the IV dose and dilute before administration.

Reversal of Adverse Muscarinic Effects of Anticholinesterases

IV (Adults ): 0.6–12 mg for each 0.5–2.5 mg of neostigmine or 10–20 mg of pyridostigmine concurrently with anticholinesterase.

Organophosphate Poisoning

IV (Adults ): 1–2 mg/dose every 10–20 min until atropinic effects observed then every 1–4 hr for 24 hr; up to 50 mg in first 24 hr and 2 g over several days may be given in severe intoxication.
IV (Children ): 0.02–0.05 mg/kg every 10–20 min until atropinic effects observed then every 1–4 hr for 24 hr.

Bronchospasm

Inhaln (Adults ): 0.025–0.05 mg/kg/dose every 4–6 hr as needed; maximum 2.5 mg/dose.
Inhaln (Children ): 0.03–0.05 mg/kg/dose 3–4 times/day; maximum 2.5 mg/dose.

Availability ⬆ ⬇

(Generic available)

Solution for injection: 0.05 mg/mL; 0.1 mg/mL; 0.4 mg/mL; 1 mg/mL

Assessment ⬆ ⬇

Assess vital signs and ECG tracings frequently during IV drug therapy. Report any significant changes in heart rate or BP, or increased ventricular ectopy or angina to health care professional promptly.
- Monitor intake and output ratios in elderly or surgical patients because atropine may cause urinary retention.
- Assess patients routinely for abdominal distention and auscultate for bowel sounds. If constipation becomes a problem, increasing fluids and adding bulk to the diet may help alleviate constipation.

Implementation ⬆ ⬇

Endotracheal: Dilute with 5–10 mL of 0.9% NaCl.
Rate: Inject directly into the endotracheal tube followed by several positive pressure ventilations.

IV Administration:

IV Push: Diluent: Administer undiluted.
Rate: Administer over 1 min; more rapid administration may be used during cardiac resuscitation (follow with 20 mL saline flush). Slow administration (over >1 min) may cause a paradoxical bradycardia (usually resolved in approximately 2 min).
Y-Site Compatibility:
- amikacin
- aminophylline
- amiodarone
- argatroban
- ascorbic acid
- azathioprine
- aztreonam
- benztropine
- bivalirudin
- bumetanide
- buprenorphine
- butorphanol
- calcium chloride
- calcium gluconate
- cangrelor
- cefazolin
- cefotaxime
- cefotetan
- cefoxitin
- ceftazidime
- ceftriaxone
- cefuroxime
- chloramphenicol
- chlorpromazine
- clindamycin
- cyanocobalamin
- cyclosporine
- dexamethasone
- dexmedetomidine
- digoxin
- diphenhydramine
- dobutamine
- dopamine
- doxycycline
- enalaprilat
- ephedrine
- epinephrine
- epoetin alfa
- eptifibatide
- erythromycin
- esmolol
- etomidate
- famotidine
- fentanyl
- fluconazole
- folic acid
- furosemide
- ganciclovir
- gentamicin
- glycopyrrolate
- heparin
- hydrocortisone
- hydromorphone
- imipenem/cilastatin
- indomethacin
- insulin, regular
- isoproterenol
- ketamine
- ketorolac
- labetalol
- LR
- lidocaine
- magnesium sulfate
- mannitol
- meperidine
- meropenem
- methadone
- methylprednisolone
- metoclopramide
- metoprolol
- midazolam
- morphine
- multivitamins
- nafcillin
- nalbuphine
- naloxone
- nitroglycerin
- nitroprusside
- norepinephrine
- ondansetron
- oxacillin
- oxytocin
- palonosetron
- papaverine
- penicillin G
- pentamidine
- pentobarbital
- phenobarbital
- phentolamine
- phenylephrine
- phytonadione
- potassium chloride
- procainamide
- prochlorperazine
- promethazine
- propranolol
- protamine
- pyridoxine
- sodium bicarbonate
- succinylcholine
- sufentanil
- theophylline
- thiamine
- tirofiban
- tobramycin
- vancomycin
- vasopressin
- verapamil
Y-Site Incompatibility:
- acetaminophen
- dantrolene
- diazepam
- pantoprazole
- phenytoin
- trimethoprim/sulfamethoxazole
- thiopental

Patient/Family Teaching ⬆ ⬇

Explain purpose of atropine to patient.
May cause drowsiness. Caution patients to avoid driving or other activities requiring alertness until response to medication is known.Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
- Instruct patient that oral rinses, sugarless gum or candy, and frequent oral hygiene may help relieve dry mouth.
- Caution patients that atropine impairs heat regulation. Strenuous activity in a hot environment may cause heat stroke.
- Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
- Instruct parents or caregivers that medication may cause fever and to notify health care professional before administering to a febrile child.
- Inform male patients with benign prostatic hyperplasia that atropine may cause urinary hesitancy and retention. Changes in urinary stream should be reported to health care professional.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇