Dangerous Amounts of Montelukast (Singulair)
Montelukast is remarkably safe in overdose, with doses up to 536 mg or 33.71 mg/kg in children producing only minor effects and no serious or life-threatening adverse events. 1
Toxicity Profile of Montelukast
Montelukast is a leukotriene receptor antagonist commonly prescribed for asthma and allergic rhinitis. The evidence strongly suggests it has an excellent safety profile even in significant overdose situations:
Normal Therapeutic Dosing
- Adults (≥15 years): 10 mg once daily 2, 3
- Children (6-14 years): 5 mg once daily 2, 3
- Children (1-5 years): 4 mg once daily 2
Overdose Information
In a comprehensive analysis of 17,069 montelukast exposures in children aged 5-17 years:
- Abdominal pain was the most common adverse event (0.23% overall)
- Even with ultra-high doses (≥50 mg), abdominal pain occurred in only 1.46% of cases
- No serious or life-threatening events were reported with doses up to 445 mg 1
Another study examining 3,698 pediatric exposures found:
- 95% of cases resulted in no observed effects
- Only 5% had minor effects with doses up to 536 mg or 33.71 mg/kg
- No serious adverse effects were reported 4
Case reports document:
Clinical Management of Overdose
When to Seek Medical Care
- Home observation is appropriate for most accidental ingestions 4
- Healthcare facility evaluation may be considered for:
- Doses >100 mg (56% of such cases were managed in healthcare facilities)
- Doses >5 mg/kg (47% of such cases were managed in healthcare facilities) 4
Monitoring Parameters
- Abdominal discomfort (most common symptom)
- Gastrointestinal symptoms (nausea, vomiting)
- No specific antidote is required as serious toxicity is not expected
Special Considerations
Safety in Context
- Montelukast has demonstrated a tolerability profile similar to placebo in both short-term and long-term administration 6
- Even doses up to 200 mg per day (20 times the recommended dose) administered for 5 months showed no dose-related adverse effects in adults 6
Potential Pitfalls
- Don't confuse montelukast with other medications that may have significant toxicity in overdose
- The excellent safety profile of montelukast should not lead to complacency about medication safety in general
- While montelukast itself appears quite safe in overdose, always consider the possibility of co-ingestions with other medications that may be more toxic
In conclusion, montelukast demonstrates an exceptional safety profile even in significant overdose situations, with minimal clinical effects reported at doses many times the therapeutic recommendation.