Hydralazine (Hydralazine Hydrochloride) - Drug Interactions, Contraindications, Overdosage

DRUG INTERACTIONS

Drug Interactions: MAO inhibitors should be used with caution in patients receiving hydralazine.

When other potent parenteral antihypertensive drugs, such as diazoxide, are used in combination with hydralazine, patients should be continuously observed for several hours for any excessive fall in blood pressure. Profound hypotensive episodes may occur when diazoxide injection and hydralazine injection are used concomitantly.

OVERDOSAGE

Acute Toxicity: No deaths due to acute poisoning have been reported.

Highest known dose survived: adults, 10 g orally.

Oral LD₅₀ in rats: 173 and 187 mg/kg.

Signs and Symptoms: Signs and symptoms of overdosage include hypotension, tachycardia, headache, and generalized skin flushing.

Complications can include myocardial ischemia and subsequent myocardial infarction, cardiac arrhythmia, and profound shock.

Treatment: There is no specific antidote.

Support of the cardiovascular system is of primary importance. Shock should be treated with plasma expanders. If possible, vasopressors should not be given, but if a vasopressor is required, care should be taken not to precipitate or aggravate cardiac arrhythmia. Tachycardia responds to beta blockers. Digitalization may be necessary, and renal function should be monitored and supported as required.

No experience has been reported with extracorporeal or peritoneal dialysis.

CONTRAINDICATIONS

Hypersensitivity to hydralazine; coronary artery disease; mitral valvular rheumatic heart disease.