27.01 Hydralazine

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  1. Hydralazine- direct acting vasodilator
    1. Indications
      1. Hypertension
      2. Heart failure
    2. Mechanism of action
      1. Unclear
      2. 3 types of mechanism suggested
        1. Releases nitric oxide from vascular endothelial cells causing vasodilation
        2. Blocks the entry of calcium in the smooth muscle cells and causing vasodilation.
        3. Opening the potassium channels causing the hyperpolarization and causing the vasodilation


  1. Hydralazine is often given in hospital to quickly lower blood pressure
  2. Often given with a diuretic for best effect


  1. Assessing for side effects
    1. Headache
    2. Dizziness
    3. Flushing
    4. Tachycardia and palpiations
    5. Edema

Therapeutic Management

  1. Monitor blood pressure frequently at the start of therapy
  2. Discontinue slowly to avoid rapid rise in blood pressure

Nursing Concepts

  1. Perfusion
    1. Hydralazine affects perfusion by decreasing the work load of the heart.
  2. Pharmacology
    1. Hydralazine is often prescribed to treat hypertension.

Patient Education

  1. Caution patients to avoid sudden changes in position to prevent orthostatic hypotension.
  2. Patients should weigh themselves and monitor for fluid retention.
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So, in this one, we gonna talk about the hydralazine. This medication doesn’t fall in any category because its mechanism of actions is really unknown. There are many mechanisms are suggested and nothing’s really established with this medication. So, we can say this medication is direct-acting vasodilator. So, that’s just like its own drug, no category.

Let’s talk about the mechanism of action. It is not clear at all. So, here, you can see, there are like 3 types of mechanism suggested that this medication may be working by, but nothing specific. The first one is by releasing nitric oxide from vascular endothelial cells and causing vasodilation. Same as nitroglycerin and sodium nitroprusside like nitro compounds. Or, maybe, by blocking the entry of calcium in the smooth muscle cells and causing vasodilation, same as calcium-channel blocker. And this is not specific, they’re thinking it may be working by that or both. Or, it maybe opening the potassium channels and causing the hyperpolarization and causing the vasodilation. So, these 3 mechanism of action are not, they think the medication maybe working by this mechanism but nothing specific. This mechanism, depending on the mechanism, causes the vasodilation.

This medication maybe used for hypertension, and heart failure. The reason we use this medication for the heart failure, because when we decrease the blood pressure, it’s basically decreasing the afterload. So, when heart left ventricle pumps up the blood into the aorta. If it is decreased blood pressure, that means if aorta and all the arteries are dilated, the left ventricle doesn’t have to push hard or pump hard in order to eject the blood out of the heart into the systemic circulation. So, that’s why it decreases the work load of the heart by decreasing the blood pressure and that’s why it can be used in heart failure as well. But the main reason or the main use for this medication have seen quite often in hospitals or if a patient has high blood pressure.

What are the side effects? This medication works by dilating the vessels, it causes the headache, because when you have dilated vessels in the brain, it holds more blood, it causes the pressure on the brain cells, it causes the headache. So, like, the way it works. It causes the flushing, tachycardia, and lupus like syndrome. And this is the main one, not really often, but sometime they may ask this Hydralizine causes side effects, so, Lupus like syndrome, it can cause.

So, this is really a short drug and this doesn’t fall in any category, so, I just want to cover it separately, mainly used for the hypertension. If you have any question about this drug, feel free to ask us questions. Thanks for watching.

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