What is the toxic dose of dicyclomine (dicycloverine) in adults and children?

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Last updated: November 10, 2026 • View editorial policy

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Toxic Dose of Dicyclomine

The toxic dose of dicyclomine is not precisely defined, but documented overdoses include 600 mg in a 10-month-old child and approximately 1500 mg in an adult, both of whom survived, while fatal cases in infants have occurred with blood concentrations of 200-505 ng/mL. 1

Documented Toxic Exposures

Adults

  • Maximum recorded oral dose: Approximately 1500 mg (survived) 1
  • Symptomatic overdose case: A 37-year-old experienced numbness, cold fingertips, blurred vision, abdominal pain, decreased appetite, dry mouth, and nervousness after ingesting 320 mg daily (four 20 mg tablets four times daily). These symptoms resolved after discontinuation 1

Children

  • Maximum recorded oral dose: 600 mg in a 10-month-old child (survived) 1
  • Fatal cases: Three infants died with blood concentrations of 200,220, and 505 ng/mL 1, 2
  • The 505 ng/mL level was nearly 10 times the reported adult therapeutic blood concentrations 2

Clinical Manifestations of Overdose

Anticholinergic toxicity presents with:

  • Headache, nausea, vomiting
  • Blurred vision, dilated pupils
  • Hot, dry skin
  • Dizziness, dry mouth, difficulty swallowing
  • CNS stimulation including convulsions
  • Curare-like action: Neuromuscular blockade leading to muscular weakness and possible paralysis 1

Critical Considerations

Infants are at particularly high risk - dicyclomine has caused fatal respiratory complications in infants, and the drug should be used with extreme caution in this population 1. The therapeutic window appears narrower in pediatric patients compared to adults.

Acute Oral LD50

  • Animal data: 625 mg/kg in mice 1
  • This translates to approximately 43,750 mg for a 70 kg adult, though human toxicity occurs at far lower doses

Management Approach

Treatment consists of:

  1. Gastric lavage and emetics (if presenting early)
  2. Activated charcoal
  3. Sedatives (short-acting barbiturates or benzodiazepines) for management of excitement/agitation
  4. Parenteral cholinergic agents as antidote if indicated 1

Note: Dicyclomine is not known to be dialyzable 1, limiting extracorporeal treatment options.

Key Clinical Pitfall

The amount of drug in a single dose that is ordinarily associated with life-threatening symptoms has not been precisely defined 1. This lack of a clear toxic threshold means clinicians must maintain a low threshold for monitoring any patient with suspected dicyclomine overdose, particularly given the potential for severe anticholinergic crisis and neuromuscular blockade.

References

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.