HWN Suggests

Hydralazine is Broken (No Need to Fix It)

Hydralazine is much like rolling the dice on blood pressure management. You do not know when the blood pressure will change or what level to expect it to drop. Following its administration, hydralazine has a latent period ranging from five to 15 minutes before onset of action, and after onset it can cause an abrupt fall in blood pressure lasting up to 12 hours...

Perhaps the perception is that hydralazine is a benign medication and that one dose of hydralazine can't possibly be that harmful. Sadly, given its long half-life, adverse effects may not be recognized or connected to hydralazine if they occur hours later, prompting the clinician to make poor reactionary decisions.

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 Hydralazine inhibits cysteamine dioxygenase to treat preeclampsia and senesce glioblastoma

The potent and direct vasodilatory activity of HYZ has secured its place on the World Health Organization’s list of essential medicines (2) for the clinical treatment of hypertensive crisis (3) and (pre)eclampsia (3, 4), a hypertension-associated obstetric emergency that is the leading cause of maternal and fetal mortality. However, it has been supplanted by newer drugs in most of its other original indications (e.g., subacute hypertension). The primary reason is that HYZ has both unfavorable pharmacokinetics and serious side effects, including, for example, a lupus-like autoimmune syndrome, blood disorders, and nerve and liver toxicity.

 Penn researchers find common blood pressure medicine can prevent brain cancer cell growth

A group of Penn researchers found that a common blood pressure medicine can be used to prevent brain cancer cells from growing. After trying to understand how the drug, hydralazine, works at a molecular level, the researchers discovered that it blocks a certain oxygen-sensing enzyme. They later discovered that the same enzyme can be used to prevent brain cancer cells from growing.

Articles of Interest

Hypertensive Emergency: Pearls and Pitfalls for the ED Physician

Hydralazine and diuretics have limited value, and in-fact a potential for harm if used for hypertensive emergency. Hydralazine remains extensively used despite its suboptimal pharmacokinetics and the substantial, unpredictable antihypertensive response.2 After IV administration, there is an initial latency period of up to 15 minutes, followed by sporadic, progressive and often precipitous decline in BP.26 Furthermore, don’t let the half-life of 3 hours deceive you, as the pharmacologic response to hydralazine can persist for up to ~8-12 hours.27,28 Taken together, the unpredictable response and difficulty in titration, its use is best avoided in the management of hypertensive crises.

Retrospective review of the use of as-needed hydralazine and labetalol for the treatment of acute hypertension in hospitalized medicine patients

Several studies have demonstrated the inappropriate use of PRN intravenous (IV) hydralazine and labetalol for the management of severe blood pressure elevations in hospitalized patients.

Vasodilator Drugs: Chronic Vasodilator Therapy – Hydralazine

With the introduction of angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and beta-adrenergic blockers, chronic vasodilator therapy has moved into a second- or third-level therapy for chronic heart failure. At the present time, chronic oral vasodilator therapy consists of hydralazine, a nitrate preparation, and a combination of these two groups.

Resources

Hydralazine (Apresoline)

Initiate therapy in gradually increasing dosages; adjust according to individual response. Start with 10 mg four times daily for the first 2 to 4 days, increase to 25 mg four times daily for the balance of the first week.

GoodRx

It is not a first-choice drug, but it can be helpful for people who have high blood pressure and other first-choice drugs are not working.

ScienceDirect

Hydralazine exerts a preferential effect on arterioles compared with veins. The resulting changes are decreased peripheral resistance; decreased blood pressure; and reflexively increased heart rate, stroke volume, and CO.

StatPearls

In current practice, oral hydralazine is used in essential hypertension refractory to other therapeutic agents. Studies comparing its effects as an add-on medication to multidrug treatment for hypertension have proved effective but not as efficacious as other multi-modal first-line therapies (calcium channel blockers, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, thiazides).