Electrocardiographic Changes Following Acute Hydralazine Overdose

Hydralazine is an FDA-approved antihypertensive agent which has been utilized for years either alone or in combination with other medications especially the beta-blockers. Hydralazine works as a direct-acting vasodilator, thereby exerting a decrease in vascular resistance and increase in intravascular volume. When overdosed, hydralazine applies its toxic effects by extending its pharmacological action, which produces hypotension, syncope, tachycardia, and nausea. However, studies and case reports of acute hydralazine toxicity and its effects on electrocardiographic changes are rare, and most of the medical literature have only highlighted its immunological side effects. In this report, we are presenting a case of acute hydralazine overdose in a young woman who ended up in CCU due to remarkably abnormal electrocardiogram and unstable hemodynamics followed by myocardial infarction.

[Importance of toxicological studies in animals for elaboration of pathogenetic therapy of hydrazine intoxication]

Pathogenesis of poisoning with hydrazine seems complicated. Hydrazines inhibit pyridoxal-dependent enzymes, interfere with carbohydrates transformation and lipid metabolism, alter the processes of energy metabolism. Treatment of poisoning with hydrazine is effective only when containing drug combinations. Based experimentally, recommendations on the combination (phenazepam, be methyl, piracetam, ionol) were supported by chemical testing of the drugs.

Acute hydralazine overdose: marked ECG abnormalities in a young adult

Although hydralazine is a commonly prescribed antihypertensive agent, reports of acute human poisoning are uncommon. Most of the literature focuses on chronic toxicity, most notably, the drug-induced systemic lupus erythematosus syndrome. A case of acute hydralazine overdose associated with marked ECG ST segment depression in a young adult is presented. Although the patient also had mild hypotension, acidemia, and ethanol intoxication, the ECG abnormality was alarming and suggestive of myocardial ischemia. The patient was managed conservatively in an ICU setting, and the metabolic and ECG abnormalities resolved. No reports of such marked ECG changes associated with acute hydralazine poisoning in a young adult could be found. Clinical and experimental data on acute hydralazine exposure suggest that the possibility of direct drug effects, including positive inotropic and chronotropic effects and myocardial cell injury, should be considered.