Atropine Side Effects
For the Consumer
Applies to atropine: oral tablets, parenteral injection
Side effects include:
Most adverse effects are manifestations of pharmacologic effects at muscarinic-cholinergic receptors and usually are reversible when therapy is discontinued.
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.
Frequent effects include xerostomia (dry mouth), dry skin, blurred vision, cycloplegia, mydriasis, photophobia, anhidrosis, urinary hesitancy and retention, tachycardia, palpitation, xerophthalmia, and constipation, which may appear at therapeutic or subtherapeutic doses. Xerostomia is the dose-limiting effect.
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), fever, mild to moderate pain at the injection site, loss of libido, and erectile dysfunction (via block of cholinergically mediated vasodilation).
For Healthcare Professionals
Applies to atropine: compounding powder, injectable solution, intravenous solution, oral tablet
Although individual reactions vary greatly, systemic doses are likely to produce the following effects:
0.5 mg: Slight dryness of the nose and mouth, bradycardia
1 mg: Greater dryness of nose and mouth with thirst; slowing, then acceleration of the heart; slight mydriasis
2 mg: Very dry mouth, tachycardia with palpitations, mydriasis, slight blurring of near vision
5 mg: Increase in the above symptoms plus disturbance of speech, difficulty swallowing, headache, hot, dry skin, restlessness with asthenia
10 mg and over: Above symptoms to extreme degrees, plus ataxia, excitement, disorientation, hallucinations, delirium, and coma
65 mg: May be fatal[Ref]
Common (1% to 10%): Tachycardia (arrhythmias, transient exacerbation of bradycardia)
Very rare (less than 0.01%): Atrial arrhythmias, ventricular fibrillation, angina, hypertensive crisis
Frequency not reported: Bradycardia, slowing then acceleration of heart, palpitations, circulatory collapse, blood pressure declines, sinus tachycardia, supraventricular tachycardia, junctional tachycardia, ventricular tachycardia, ventricular flutter, ventricular fibrillation, atrial arrhythmia, atrial fibrillation, atrial ectopic beats, ventricular premature contractions, bigeminal beats, trigeminal beats, nodal extrasystole, supraventricular extrasystole, asystole, cardiac syncope, prolongation of sinus node recovery time, cardiac dilation, left ventricular failure, myocardial infarction, intermittent nodal rhythm (no P wave), prolonged P wave, shortened PR segment, R on T phenomenon, shortened RT duration, widening and flattening of QRS complex, prolonged QT interval, flattening of T wave, repolarization abnormalities, altered ST-T waves, retrograde conduction, transient AV dissociation, increased blood pressure, labile blood pressure, weak or impalpable peripheral pulses, paradoxical atrioventricular block[Ref]
Very common (10% or more): Loss of taste
Common (1% to 10%): Incoordination
Uncommon (0.1% to 1%): Seizure, drowsiness
Frequency not reported: Disturbance of speech, headache, asthenia, ataxia, coma, dizziness, tremor, locomotor difficulties, medullary paralysis, neurological abnormalities, lethargy, somnolence, syncope, runs of alpha waves on EEG, alpha waves (EEG) blocked upon opening eyes, seizures (generally tonic-clonic), abnormal movements, stupor, amnesia, diminished tendon reflexes, hyperreflexia, opisthotonos, Babinski's reflex/Chaddock's reflex, hypertonia, dysmetria, muscle clonus, sensation of intoxication, difficulty concentrating, vertigo, dysarthria, loss of taste, giddiness, staggering[Ref]
Very common (10% or more): Visual disturbances (mydriasis, inhibition of accommodation, blurred vision, photophobia)
Frequency not reported: Blurring of near vision, pupils poorly reactive to light, decreased contrast sensitivity, decreased visual acuity, cycloplegia, strabismus, heterophoria, cyclophoria, acute angle closure glaucoma, conjunctivitis, keratoconjunctivitis sicca, blindness, tearing, dry eyes/dry conjunctiva, irritated eyes, crusting of eyelids, blepharitis, increase in photic stimulation on EEG, increase in intraocular pressure[Ref]
Very common (10% or more): Dryness of mouth (difficulty swallowing and talking, thirst), parasympathetic inhibition of gastrointestinal tract (constipation and reflux), inhibition of gastric secretion, nausea, vomiting, bloated feeling
Frequency not reported: Abdominal distension, abdominal pain, paralytic ileus, decreased bowel sounds, delayed gastric emptying, decreased food absorption, dysphagia, retrosternal pain due to gastric reflux[Ref]
Very common (10% or more): Anhidrosis, urticaria, rash
Common (1% to 10%): Flushing
Frequency not reported: Dry skin, hot skin, scarlatiniform rash, skin rashes, exfoliation, dry mucus membranes, warm skin, maculopapular rash, erythematous rash, sweating/moist skin, cold skin, cyanosed skin, salivation[Ref]
Common (1% to 10%): Excitement, confusion, hallucinations
Uncommon (0.1% to 1%): Psychotic reactions
Frequency not reported: Restlessness, disorientation, delirium, loss of libido, delirium, depression, manic behavior, irritability, agitation, insomnia, agitation, paranoia, anxiety, mental disorders, mania, withdrawn behavior, behavior changes, nervousness[Ref]
Common (1% to 10%): Hyperthermia
Frequency not reported: Death, fever, heat intolerance, impairment of temperature regulation (especially in a hot environment), fatigue, hyperpyrexia, chest pain, weakness, feeling hot, signs of drowsiness on EEG[Ref]
Common (1% to 10%): Inhibition of parasympathetic control of the urinary bladder, urinary retention
Frequency not reported: Urinary hesitancy, impotency, difficulty in micturition, urine urgency, distended urinary bladder, bed wetting[Ref]
Rare (less than 0.1%): Allergic reactions
Very rare (less than 0.01%): Anaphylaxis
Frequency not reported: Hypersensitivity[Ref]
Frequency not reported: Dryness of nose, respiratory failure, tachypnea, slow respirations, shallow respirations, inspiratory stridor, laryngitis, laryngospasm, pulmonary edema, subcostal recession, reduced bronchial secretions, formation of bronchial plugs[Ref]
Frequency not reported: Thirst, excessive thirst, dehydration, hyponatremia, hypokalemia, hypoglycemia, hyperglycemia[Ref]
Frequency not reported: Muscle twitching[Ref]
Frequency not reported: Pain at injection site, local swelling, injection site reaction, redness or other signs of irritation at the injection site[Ref]
Frequency not reported: Leukocytosis, elevated hemoglobin, elevated erythrocytes, low hemoglobin[Ref]
Frequency not reported: Elevated BUN[Ref]
1. "Product Information. Atropine Sulfate (atropine)." American Regent Laboratories Inc, Shirley, NY.
2. "Product Information. Atropine Sulfate Injection, USP (atropine)." ESI Lederle Generics, Philadelphia, PA.
3. Cerner Multum, Inc. "Australian Product Information." O 0
4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
5. "Product Information. AtroPen (atropine)." Meridian Medical Technologies Inc, Columbia, MD.
Not all side effects for atropine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
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- Drug class: anticholinergic chronotropic agents
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