Bad Habits Die Hard: A Love Affair With Hydralazine

There are a handful of antihypertensive agents that have been around for a long time. One of these medications is hydralazine. It has carved out niche status in a number of clinical situations.

First, hydralazine is utilized for the treatment of ambulatory hypertension. Unfortunately, there has never been a controlled study demonstrating its efficacy, adverse effects, and benefits regarding morbidity and mortality compared with placebo!¹ Then it became a go-to agent for third-trimester hypertension, despite evidence that its use lowered Apgar scores in newborns and increased the incidence of maternal hypotension as well as abruption!² Finally, it has assumed status as a parenteral savior for in-patient hypertensive episodes that are not hypertensive emergencies.

This month’s Top Paper³ has something to say about the final hydralazine therapeutic niche. Some of what is said about the goose—in this instance, hydralazine—is also good for the ganders (enalaprilat, labetalol, and metoprolol).

The study population was noncritically ill in-patients with an intravenous order for enalaprilat, labetalol, hydralazine, or metoprolol. The investigators analyzed blood pressure thresholds for ordering lowering therapy and the effect of such therapy on short-term blood pressures and adverse outcomes. Blood pressure changes during the hospitalization were compared between those people who did and did not receive parenteral antihypertensive therapy, and also between those who did not and did not receive intensifications of their ambulatory blood pressure medications.

A total of 246 patients had an order for in-patient parenteral treatment of elevated blood pressures. Approximately one-third of the treated hypertensive patients experienced a drop in blood pressure of more than 25% within 6 hours. Only approximately one-half of treated patients had their ambulatory medications adjusted.

The authors drew some important conclusions. The orders for parenteral in-patient antihypertensives are written without any assessment of risk in patients who are asymptomatic and who are not experiencing target organ injury. The medicines utilized are not typical ambulatory agents, and some have little data to support their use at all. Some of the patients in the treated group became hypotensive. The investigators observed that authors of other similar studies have reported ischemic complications in patients in the treatment group.

Resist the urge to treat uncomplicated, asymptomatic in-patient hypertension with parenteral agents. Do not forget to adjust home going regimens for elevated blood pressures instead.

Gregory W. Rutecki, MD, is a physician at the National Consult Service at the Cleveland Clinic. He is also a member of the Consultant editorial board.

References:

1. Kandler MR, Mah GT, Tejani AM, Stabler SN, Salzwedel DM. Hydralazine for essential hypertension. Cochrane Database Syst Rev. 2011;(11):CD004934. doi:10.1002/14651858.CD004934.pub4.
2. Seely EW, Ecker J. Clinical practice: chronic hypertension in pregnancy. N Engl J Med. 2011;365(5):439-446.
3. Lipari M, Moser LR, Petrovitch EA, Farber M, Flack JM. As-needed intravenous antihypertensive therapy and blood pressure control. J Hosp Med. 2016;11(3):193-198.