If you’re among the 108 million U.S. adults with high blood pressure, chances are you’ve had a conversation with your doctor about taking medication to handle it. When blood pressure is elevated, your heart and arteries need to work extra hard to move blood through your body. Over time, this can cause damage to blood vessels and raise your chance of heart disease, stroke, heart failure or kidney failure. High blood pressure (also called hypertension) doesn’t usually have any symptoms, so it’s important to get your blood pressure checked regularly.

If you do have hypertension, your doctor may suggest taking hydralazine to keep it in check. Here are some important things to know before starting treatment. Remember, knowledge is power.

Hydralazine is used to lower blood pressure

“Hydralazine works by relaxing the blood vessels so blood can flow more easily through the body,” says Patrick Fratellone, MD, a cardiologist with Fratellone Medical Associates in New York City and Fairfield, Connecticut. This in turn lowers your blood pressure. Because hypertension is a long-term condition that may require you to take medication for the rest of your life.

Hydralazine not a first line of treatment

While this medication has been around for decades, it’s no longer a first choice for therapy, says J. Herbert Patterson, PharmD, professor and interim chair of the pharmacotherapy and experimental therapeutics division at UNC Eshelman School of Pharmacy in Chapel Hill, North Carolina. “Newer drugs are just as effective if not more so, can be given once or twice a day, and are generally better tolerated,” Patterson says.

Typically, hydralazine has to be given 3 to 4 times a day, so sticking to a dosing plan can be difficult, he adds. Your doctor may still suggest hydralazine along with another medication. “The combination of hydralazine and a diuretic [water pill] will lower blood pressure more effectively than either drug alone,” Patterson says.

Do you need help paying for your hydralazine prescription? Optum Perks can help. Download our app, type in the drug name, and receive a coupon for up to 80% off.

Hydralazine is very effective

Once you start taking hydralazine, you’ll see quick results. “This fast-acting blood pressure medication will work within 1 week of starting treatment,” Dr. Fratellone says. In addition to other common options, it can also be a good choice for African Americans who have heart failure. Patterson says doctors will usually combine the medication with a nitrate, such as isosorbide dinitrate. “It can be very helpful for improving symptoms and reducing the chance of death and hospitalization,” he explains.

Hydralazine may trigger side effects

Like most medications, hydralazine may come with some side effects. Headache, nausea, vomiting and diarrhea are all common but not serious. You’ll also want to look out for an increased heart rate, says Patterson. As hydralazine lowers blood pressure, your body compensates by increasing your heart rate to boost blood flow. In rare cases, starting this medication can also cause drug-induced lupus, says Dr. Fratellone. Stopping the medication usually reverses these symptoms.

There’s more than one way to keep your blood pressure in check. Get the scoop on fish oil and find out (with your doc’s advice) if it’s right for you.