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Toxicology – ACE Inhibitor Toxicity
Source
Angiotensin-converting enzyme (ACE) inhibitors include medications such as captopril, enalapril, lisinopril, ramipril, quinapril, fosinopril, benazepril, moexipril, and trandolapril. They are widely used to treat hypertension, heart failure, and diabetic kidney disease.
Typical Presentation
Toxicity may occur due to accidental or intentional overdose, particularly in elderly patients with multiple medications. Patients commonly present with low blood pressure and electrolyte abnormalities.
Clinical Features
Key findings include hypotension, acute kidney injury (manifesting as reduced urine output or elevated creatinine), and hyperkalemia. Elevated potassium levels can lead to cardiac conduction abnormalities and arrhythmias. In some cases, bradycardia may occur. Even at therapeutic doses, ACE inhibitors may cause cough, wheezing, and angioedema.
Mechanism of Action
ACE inhibitors block the conversion of angiotensin I to angiotensin II, resulting in decreased vasoconstriction and lower blood pressure. They also increase levels of bradykinin, which contributes to side effects such as cough and angioedema.
Management
Treatment is supportive. Intravenous fluids are typically effective for hypotension. Continuous cardiac monitoring and ECG evaluation are recommended. Laboratory monitoring should include kidney function and serum potassium. Activated charcoal may be considered in early presentations.
Hyperkalemia should be treated as indicated, using measures such as insulin with glucose, beta-agonists, potassium-binding agents, or dialysis in severe cases. Calcium gluconate or calcium chloride is used to stabilize cardiac membranes when ECG changes are present.
Angioedema requires immediate discontinuation of the drug and treatment with supportive measures, including antihistamines and corticosteroids. Airway protection may be necessary in severe cases.
Key Points
Source
Angiotensin-converting enzyme (ACE) inhibitors include medications such as captopril, enalapril, lisinopril, ramipril, quinapril, fosinopril, benazepril, moexipril, and trandolapril. They are widely used to treat hypertension, heart failure, and diabetic kidney disease.
Typical Presentation
Toxicity may occur due to accidental or intentional overdose, particularly in elderly patients with multiple medications. Patients commonly present with low blood pressure and electrolyte abnormalities.
Clinical Features
Key findings include hypotension, acute kidney injury (manifesting as reduced urine output or elevated creatinine), and hyperkalemia. Elevated potassium levels can lead to cardiac conduction abnormalities and arrhythmias. In some cases, bradycardia may occur. Even at therapeutic doses, ACE inhibitors may cause cough, wheezing, and angioedema.
Mechanism of Action
ACE inhibitors block the conversion of angiotensin I to angiotensin II, resulting in decreased vasoconstriction and lower blood pressure. They also increase levels of bradykinin, which contributes to side effects such as cough and angioedema.
Management
Treatment is supportive. Intravenous fluids are typically effective for hypotension. Continuous cardiac monitoring and ECG evaluation are recommended. Laboratory monitoring should include kidney function and serum potassium. Activated charcoal may be considered in early presentations.
Hyperkalemia should be treated as indicated, using measures such as insulin with glucose, beta-agonists, potassium-binding agents, or dialysis in severe cases. Calcium gluconate or calcium chloride is used to stabilize cardiac membranes when ECG changes are present.
Angioedema requires immediate discontinuation of the drug and treatment with supportive measures, including antihistamines and corticosteroids. Airway protection may be necessary in severe cases.
Key Points
- Angioedema can occur unpredictably, even after prolonged use.
- Chronic dry cough is a common side effect of ACE inhibitors.
- Angiotensin receptor blockers (ARBs) are less likely to cause cough or angioedema.
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