SIDE EFFECTS
The following serious adverse reactions are described
elsewhere in the labeling:
- Cardiovascular Risks [see WARNINGS AND PRECAUTIONS]
- Heat Injury [see WARNINGS AND PRECAUTIONS]
- Acute Glaucoma [see WARNINGS AND PRECAUTIONS]
- Urinary Retention [see WARNINGS AND PRECAUTIONS]
- Pyloric Stenosis [see WARNINGS AND PRECAUTIONS]
- Exacerbation of Chronic Lung Disease [see WARNINGS AND
PRECAUTIONS]
- Hypersensitivity [see WARNINGS AND PRECAUTIONS]
The following adverse reactions associated with the use
of atropine were identified in the literature. Because these reactions are
reported voluntarily from a population of uncertain size, it is not always
possible to reliably estimate their frequency or establish a causal
relationship to drug exposure.
Injection Site Reactions
Mild to moderate pain may be experienced at the site of
injection.
Adverse Reactions At Recommended Dosages
The major and most common side effects of atropine can be
attributed to its antimuscarinic action. These include dryness of the mouth,
blurred vision, dry eyes, photophobia, confusion, headache, dizziness, fatigue,
tachycardia, palpitations, flushing, urinary hesitance or retention,
constipation, abdominal pain, abdominal distention, nausea, vomiting, loss of
libido, and impotency. Anhidrosis may produce heat intolerance and impairment
of temperature regulation especially in a hot environment.
Hypersensitivity
Hypersensitivity reactions will occasionally occur with
atropine; these are usually seen as skin rashes, on occasion progressing to
exfoliation. Anaphylactic reactions have occurred.
Additional Adverse Reactions To Atropine By Organ
System
The following adverse reactions were reported in
published literature for atropine in both adults and pediatric patients:
Cardiovascular
Sinus tachycardia, supraventricular tachycardia,
junctional tachycardia, ventricular tachycardia, bradycardia, palpitations,
ventricular arrhythmia, ventricular flutter, ventricular fibrillation, atrial
arrhythmia, atrial fibrillation, atrial ectopic beats, ventricular premature
contractions, bigeminal beats, trigeminal beats, nodal extrasystole,
ventricular 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,
decreased blood pressure, labile blood pressure, weak or impalpable peripheral
pulses.
Eye
Mydriasis, pupils poorly reactive to light, decreased
contrast sensitivity, decreased visual acuity, decreased accommodation,
cycloplegia, strabismus, heterophoria, cyclophoria, acute angle closure
glaucoma, conjunctivitis, keratoconjunctivitis sicca, blindness, tearing, dry
conjunctiva, irritated eyes, crusting of eyelid, blepharitis.
Gastrointestinal
Paralytic ileus, decreased bowel sounds, delayed gastric
emptying, decreased food absorption, dysphagia.
General
Hyperpyrexia, lethargy, somnolence, chest pain, excessive
thirst, weakness, syncope, insomnia, tongue chewing, dehydration, feeling hot.
Special Investigations
Leukocytosis, hyponatremia, elevated BUN, elevated
hemoglobin, elevated erythrocytes, low hemoglobin, hypoglycemia, hyperglycemia,
hypokalemia, increase in photic stimulation on EEG, signs of drowsiness on EEG,
runs of alpha waves on EEG, alpha waves (EEG) blocked upon opening eyes.
Metabolic
Failure to feed.
Central Nervous System
Ataxia, hallucinations (visual or aural), seizures
(generally tonic-clonic), abnormal movements, coma, stupor, amnesia, diminished
tendon reflexes, hyperreflexia, muscle twitching, opisthotnos, Babinski's
reflex/Chaddock's reflex, hypertonia, dysmetria, muscle clonus, sensation of
intoxication, difficulty concentrating, vertigo, dysarthria.
Psychiatric
Agitation, restlessness, delirium, paranoia, anxiety,
mental disorders, mania, withdrawn behavior, behavior changes.
Genitourinary
Difficulty in micturation, urine urgency, distended
urinary bladder, bed-wetting.
Pulmonary
Tachypnea, slow respirations, shallow respirations,
breathing difficulty, labored respirations, inspiratory stridor, laryngitis,
laryngospasm, pulmonary edema, respiratory failure, subcostal recession.
Dermatologic
Dry mucous membranes, dry warm skin, oral lesions,
dermatitis, petechiae, rash, macular rash, papular rash, maculopapular rash,
scarlatiniform rash, erythematous rash, sweating/moist skin, cold skin,
cyanosed skin, salivation.
Adverse Reactions Caused By Inadvertent Injection
Administering additional 2 mg Atropine autoinjectors by
mistake in the absence of actual nerve agent or insecticide poisoning may cause
an overdose of atropine which could result in temporary incapacitation (inability
to walk properly, see clearly or think clearly for several or more hours).
Patients with cardiac disease may be at risk for serious adverse events,
including death.
Adverse Reactions Observed In Pediatric Patients After
Inappropriate Administration Of Atropine
Amitai et al. (JAMA 1990) evaluated the safety of an
atropine autoinjector in a case series of 240 children who received the
atropine inappropriately (i.e., no nerve agent exposure) during the 1990 Gulf
War Period. Overall, severity of atropinization followed a nonlinear
correlation with dose. Estimated doses up to 0.045 mg/kg produced no signs of
atropinization. Estimated doses between 0.045 mg/kg to 0.175 mg/kg and even
greater than 0.175 mg/kg were associated with mild and severe effects respectively.
Actual dosage received by children may have been considerably lower than
estimated since incomplete injection in many cases was suspected. Regardless,
adverse events reported were generally mild and self-limited. Few children
required hospitalization. Adverse reactions reported were dilated pupils (43%),
tachycardia (39%), dry membranes (35%), flushed skin (20%), temperature 37.8° C
or 100° F (4%), and neurologic abnormalities (5%). There was also local pain
and swelling. In patients with electrocardiograms, 22 of 91 (24%) children had
severe tachycardia of 160-190 bpm. Neurologic abnormalities consisted of
irritability, agitation, confusion, lethargy, and ataxia. Atropine 2mg is only
approved for pediatric patients weighing more than 41kg at the recommended
dosing.
DRUG INTERACTIONS
Pralidoxime
When atropine and pralidoxime are used together, the
signs of atropinization (flushing, mydriasis, tachycardia, dryness of the mouth
and nose) may occur earlier than might be expected when atropine is used alone
because pralidoxime may potentiate the effect of atropine. Excitement and manic
behavior immediately following recovery of consciousness have been reported in
several cases. However, similar behavior has occurred in cases of
organophosphate poisoning that were not treated with pralidoxime.
Barbiturates
Barbiturates are potentiated by the anticholinesterases;
therefore, barbiturates should be used cautiously in the treatment of
convulsions resulting from exposure to Atropine.