Effects of Mucinex (Guaifenesin) Overdose
Mucinex (guaifenesin) overdose primarily causes central nervous system depression and gastrointestinal symptoms, with severe cases potentially leading to life-threatening complications including asystole.
Clinical Manifestations of Guaifenesin Overdose
Guaifenesin overdose can present with a spectrum of symptoms affecting multiple body systems:
Central Nervous System Effects
- Dizziness and sedation
- Central nervous system depression (can be rapid onset)
- Confusion and altered mental status
- Seizures (in severe cases)
Gastrointestinal Effects
- Nausea and vomiting
- Abdominal discomfort
- Diarrhea
Cardiovascular Effects
- Potential for cardiac arrhythmias
- In severe cases, asystole has been reported 1
Respiratory Effects
- Respiratory depression (particularly in massive overdoses)
Management of Guaifenesin Overdose
Immediate Interventions
- Contact Poison Control Center immediately 2
- Assess and secure airway, breathing, and circulation
- Establish IV access for fluid administration
- Perform continuous cardiac monitoring
Specific Management Steps
- Activated charcoal administration if patient presents within 1 hour of ingestion and is alert with intact airway reflexes
- Supportive care including:
- IV fluid resuscitation
- Correction of electrolyte abnormalities
- Respiratory support as needed
Monitoring
- Continuous cardiac monitoring
- Regular vital sign assessment
- Electrolyte monitoring
- Mental status evaluation
Special Considerations
Combination Products
Many Mucinex products contain guaifenesin combined with other medications:
- If combined with dextromethorphan: monitor for serotonin syndrome
- If combined with pseudoephedrine: monitor for hypertension, tachycardia
- If combined with acetaminophen: assess for hepatotoxicity
Documented Case Report
A case report documented a 23-year-old female who died following guaifenesin overdose. The patient experienced central nervous system depression approximately 2 hours after ingestion, followed by asystole. Post-mortem toxicology revealed high concentrations of guaifenesin in multiple tissues 1.
When to Seek Medical Attention
Patients should seek immediate medical attention if they experience:
- Severe drowsiness or difficulty staying awake
- Confusion or altered mental status
- Difficulty breathing
- Chest pain or irregular heartbeat
- Seizures
Prevention
- Keep all medications, including over-the-counter products like Mucinex, out of reach of children
- Always follow recommended dosing instructions
- Be aware that guaifenesin is present in many combination cold and cough products
- Avoid concurrent use of multiple products containing guaifenesin
While guaifenesin is generally considered safe at therapeutic doses 3, 4, overdose can lead to serious and potentially life-threatening complications. Any suspected overdose should be treated as a medical emergency requiring immediate professional attention.