Treatment of Isosorbide Dinitrate Poisoning
The treatment of isosorbide dinitrate poisoning should focus primarily on addressing hypotension through central volume expansion with intravenous normal saline and passive leg elevation, while avoiding epinephrine or other arterial vasoconstrictors which may cause more harm than good.
Clinical Manifestations of Isosorbide Dinitrate Poisoning
Isosorbide dinitrate overdose primarily causes hemodynamic effects due to its vasodilatory properties:
Cardiovascular effects:
- Hypotension (primary concern)
- Venous pooling
- Reduced cardiac output
- Bradycardia and heart block in severe cases
Neurological manifestations:
- Persistent throbbing headache
- Confusion
- Vertigo
- Syncope (especially in upright position)
- Seizures and coma in severe cases
Other symptoms:
- Visual disturbances
- Nausea and vomiting (possibly with colic and bloody diarrhea)
- Dyspnea followed by reduced ventilatory effort
- Diaphoresis with flushed or cold/clammy skin
Treatment Algorithm
1. Immediate Management
- Position the patient with passive elevation of legs to increase central fluid volume 1
- Establish IV access and begin fluid resuscitation with normal saline 1
- Monitor vital signs continuously, with special attention to blood pressure
2. Hypotension Management
- Administer intravenous normal saline for central volume expansion 1
- Avoid epinephrine or other arterial vasoconstrictors as they may cause more harm than good 1
- For patients with renal disease or heart failure, invasive hemodynamic monitoring may be required as volume expansion carries risks 1
3. Methemoglobinemia Management
- Monitor for signs of methemoglobinemia (chocolate brown blood that doesn't change color on exposure to air) 1
- If methemoglobinemia is diagnosed and clinically significant (≥10%), administer methylene blue 1-2 mg/kg intravenously 1
- Note: Significant methemoglobinemia is rare with isosorbide dinitrate overdose unless extremely large doses are consumed 1
4. Supportive Care
- Continuous cardiac monitoring
- Correct metabolic acidosis if present
- Treat seizures if they occur with standard anticonvulsant therapy
- Consider hemodialysis in severe cases, though efficacy is not well established 1
Special Considerations
- Laboratory determinations of serum isosorbide dinitrate levels are not widely available and have no established role in management 1
- No specific antagonist to the vasodilator effects of isosorbide dinitrate is known 1
- No data suggests physiological maneuvers (e.g., changing urine pH) that might accelerate elimination 1
- Patients with underlying cardiovascular disease may be more susceptible to hemodynamic effects
Common Pitfalls to Avoid
- Do not use epinephrine or arterial vasoconstrictors - this can worsen outcomes 1
- Do not overlook volume status in heart failure or renal patients - careful monitoring is essential as volume expansion can be hazardous 1
- Do not miss methemoglobinemia - though rare, it can occur with significant overdoses and requires specific treatment 1
- Do not assume all symptoms are from direct vasodilation - monitor for complications like seizures or coma that may require additional management
While some research suggests isosorbide dinitrate may have potential benefits in cyanide poisoning 2, 3, 4, this is unrelated to the management of isosorbide dinitrate poisoning itself.