Hydralazine (Apresoline)

Anesthesia Implications

Classification: hydrazinophthalazine, Antihypertensive, Vasodilator
Therapeutic Effects: ⬇BP ⬇SVR ⬆HR ⬆RAAS; Provides SUSTAINED decreases in BP
Time to Onset: 10 – 80 min (this burns a lot of people – you have to wait for the effects. Don’t redose too early!)

Duration: up to 12 hrs

Contraindications

Patients with CAD, Mitral valve rheumatic heart disease, or lupus
Caution with: Tartrazine hypersensitivity (common in those who have aspirin hypersensitivity)

Primary Considerations

Arteriolar dilator, which reduces blood pressure but increases heart rate. Used for moderate to Severe hypertension introp, HF with reduced ejection fraction, Hypertensive emergencies in pregnancy, postoperative hypertension.

Can cause adverse effects: lupus-like syndrome (glomerulonephritis) esp. in patients with high doses; blood dyscrasias, hypotension, peripherial neuritis; MI/angina induced by tachycardia

Should be avoided in patients with Lupus

IV push dose

Common Adult initial dose: 5-10 mg IV
Textbook adult: 0.1 – 0.2 mg/kg IV every 20-60 minutes
Textbook Pediatric: 0.1 – 0.2 mg/kg IV every 4-6 hours.
Maximum dose: 20 mg

Method of Action

DIRECT Guanylate cyclase agonist;

ARTERIOLAR dilation with subsequent baroreceptor reflex which increases HR

Dilation is more prevalent in coronary, cerebral, renal, and splanchnic arteries. Activates the RAAS system as well (which is working against the therapeutic effect). For the RAAS activation, those who regularly take hydralazine, there is usually a beta blocker and diuretic to counteract the effects

90% protein bound.

Metabolism

Extensive Hepatic