What are the immediate consequences and treatment for a 9-year-old child who ingested adult DayQuil (dextromethorphan and acetaminophen) and NyQuil (dextromethorphan, doxylamine, and acetaminophen)?

Immediate Management of 9-Year-Old Who Ingested Adult DayQuil and NyQuil

This child requires immediate emergency department evaluation due to the serious risk of acetaminophen hepatotoxicity, which is present in both DayQuil and NyQuil formulations. 1, 2

Immediate Actions

Contact Poison Control and Transport to ED

• All cases involving children with suicidal intent, intentional abuse, or suspected malicious intent must be referred to an emergency department immediately 3
• Do not induce emesis at home 3
• Do not administer activated charcoal at home—this should only be done by healthcare professionals in the ED if the child is asymptomatic and ingestion occurred within the preceding hour 3
• Transport immediately; do not delay for home interventions 3

Primary Toxicity Concerns

Acetaminophen Hepatotoxicity (Most Critical)

Acetaminophen is present in both DayQuil and NyQuil and poses the greatest risk for serious morbidity and mortality in this scenario. 2, 4

• Children can develop significant hepatotoxicity from acetaminophen overdose, particularly with repeated supra-therapeutic dosing 5
• The combination of multiple acetaminophen-containing products (both DayQuil and NyQuil) creates additive toxicity risk 6
• N-acetylcysteine must be administered immediately if 24 hours or less have elapsed from ingestion, without waiting for acetaminophen levels 1

Dextromethorphan Toxicity (Secondary Concern)

• Dextromethorphan is present in both formulations and can cause significant CNS effects 3, 6
• Children who ingest more than 7.5 mg/kg of dextromethorphan should be referred to the ED for evaluation 3
• Approximately 5% of persons lack normal metabolism of dextromethorphan, leading to rapid toxic levels 6
• Toxicity produces effects similar to phencyclidine (PCP) including altered mental status, hallucinations, and potential seizures 6

Doxylamine Toxicity (From NyQuil)

• NyQuil contains doxylamine, an antihistamine that can cause sedation and anticholinergic effects
• Combined with dextromethorphan, this increases CNS depression risk

Emergency Department Management Protocol

Initial Assessment and Laboratory Evaluation

The following must be obtained immediately upon ED arrival: 1, 5

• Serum acetaminophen level (draw immediately, do not wait for results to start treatment)
• Baseline liver function tests: AST, ALT, bilirubin
• Prothrombin time/INR
• Renal function: creatinine, BUN
• Electrolytes and blood glucose
• Consider dextromethorphan level if available

Gastric Decontamination

Perform gastric lavage or consider activated charcoal only if: 1, 3

• Patient is asymptomatic
• Ingestion occurred within 1 hour
• No contraindications present (altered mental status, seizures, inability to protect airway)
• If activated charcoal was given, perform lavage before administering N-acetylcysteine, as charcoal adsorbs N-acetylcysteine and reduces its effectiveness 1

N-Acetylcysteine Administration (Critical Antidote)

Begin N-acetylcysteine immediately regardless of acetaminophen level if ingestion occurred within 24 hours: 1, 2

• Loading dose: 140 mg/kg orally
• Dilute 20% solution to 5% concentration with diet cola or diet soft drink 1
• If patient vomits within 1 hour of administration, repeat that dose 1
• First maintenance dose: 70 mg/kg given 4 hours after loading dose 1
• Continue maintenance doses every 4 hours for total of 17 doses (72-hour protocol)
• If patient cannot retain oral medication, administer via duodenal intubation 1
• Standard courses may need extension if acetaminophen levels remain elevated or hepatic injury develops 2

Management of Dextromethorphan Toxicity

Monitor for and treat specific complications: 3

• For seizures: Administer intravenous benzodiazepines per standard pediatric protocols 7, 3
• For respiratory depression or severe sedation: Consider naloxone in usual opioid overdose doses (though response may be variable) 3
• For hyperthermia >40°C (104°F) from serotonin syndrome: Use benzodiazepines and external cooling measures 3

Monitoring and Follow-Up

Daily monitoring required if acetaminophen level is in potentially toxic range: 1

• Repeat AST, ALT, bilirubin daily
• Repeat prothrombin time/INR daily
• Monitor creatinine, BUN, electrolytes, blood glucose daily
• Continue N-acetylcysteine until acetaminophen undetectable and liver function normalizing 2

Critical Pitfalls to Avoid

• Do NOT use the Rumack-Matthew nomogram for chronic or repeated ingestions—it is only valid for single acute ingestions 5
• Do NOT delay N-acetylcysteine waiting for acetaminophen levels—begin immediately if within 24 hours of ingestion 1
• Do NOT assume the child is safe based on initial lack of symptoms—acetaminophen hepatotoxicity develops 24-72 hours post-ingestion 2
• Do NOT discharge until acetaminophen level returns and is interpreted—even if initially asymptomatic, patients require observation for at least 4 hours post-ingestion 3
• Be aware that approximately 5% of children may be poor metabolizers of dextromethorphan, leading to unexpectedly severe toxicity 6