Is a single dose of 25mg of cinnarizine (generic name) potentially problematic or fatal for an 8-year-old child weighing 25kg?

Safety of a Single 25mg Dose of Cinnarizine in an 8-Year-Old Child Weighing 25kg

A single 25mg dose of cinnarizine is unlikely to be problematic or fatal for an 8-year-old child weighing 25kg, though it should be monitored for potential neurological side effects.

Dosing Considerations for Cinnarizine in Children

• For children weighing less than 30kg, the recommended therapeutic dose of cinnarizine is 1.5mg/kg/day, which would be approximately 37.5mg for a 25kg child 1
• For children weighing more than 30kg, a standard single 50mg dose is typically used 1
• The standard adult dose is 5-10mg once daily, preferably taken at night to minimize daytime somnolence 2

Safety Profile of Cinnarizine in Children

• A single 25mg dose for a 25kg child (1mg/kg) is within the therapeutic range and below the recommended daily dose of 1.5mg/kg for children weighing less than 30kg 1
• Cinnarizine has been studied in children and found to be safe and effective at appropriate doses, with no serious adverse effects observed at therapeutic doses 1
• The most common side effects of cinnarizine at therapeutic doses include:
  • Drowsiness/somnolence 2
  • Mild gastrointestinal disturbances 1

Potential Concerns with Overdose

• The case report of cinnarizine toxicity in the literature involved a 30-month-old toddler who ingested 225mg, which was 18 times the recommended dose for children 3
• Symptoms of significant overdose may include:
  • Altered consciousness (somnolence to stupor) 3
  • Vomiting 3
  • Extrapyramidal symptoms 3
  • In rare cases of significant overdose in young children, convulsions 3
• The single 25mg dose in question is significantly lower than the toxic dose reported in the literature 3

Pharmacokinetic Considerations

• The elimination half-life of cinnarizine in a pediatric overdose case was approximately 3.65 hours 3
• Children aged 2 years and older have mature drug elimination pathways and differ from adults primarily in size rather than in maturation of elimination processes 4
• At 8 years old, the child would have mature drug elimination pathways, reducing concerns about drug accumulation 4

Monitoring and Precautions

• Although a single 25mg dose is unlikely to cause serious problems, it would be prudent to monitor the child for:
  • Drowsiness 2, 1
  • Dizziness or unsteady gait 3
  • Gastrointestinal symptoms like nausea or vomiting 3
• The onset of any adverse effects would typically occur within 4-6 hours after ingestion 3

Conclusion

• A single 25mg dose of cinnarizine for an 8-year-old child weighing 25kg represents a dose of 1mg/kg, which is below the recommended therapeutic dose of 1.5mg/kg 1
• This dose is unlikely to cause serious adverse effects or be fatal based on available evidence 3, 1
• The documented case of toxicity involved a dose 18 times higher than recommended, whereas this dose is within therapeutic range 3