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Treatment of hypertension

Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Tanner Marshall.

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Video transcript

- [Voiceover] So the 8th Joint National Committee, or JNC-8, has recently proposed some useful guidelines for when to treat patients with high blood pressure and what blood pressure you should be shooting for. So if you're over 60 years old, treatment should be administered to try and lower your systolic blood pressure to less than 150 millimeters of mercury, and also lower a diastolic pressure to less than 90 millimeters of mercury. If you're less than 60 years old, though, it's recommended to aim to get the blood pressure to lower than 140 millimeters of mercury on the systolic side, and again, less than 90 millimeters of mercury on the diastolic side. In addition, if you're above 18 years old and have either a chronic kidney disease or diabetes, it's also recommended to try and get your blood pressure to lower than 140 on the systolic side and lower than 90 on the diastolic side. To hit these targets, there are various treatment regimens that might be recommended or prescribed, and firstly and very importantly, lifestyle changes might be suggested, and these will almost always be used together with some sort of medication. But one suggestion is to use something called DASH, which stands for dietary approaches to stop hypertension. As the name kind of suggests, this is a diet-based lifestyle change, where we really emphasize eating foods with less sodium as well as eating whole grains, fruits, vegetables, and low fat dairy products. Another lifestyle change, a huge, huge, huge one, is to quit smoking and a bit on the same lines, alcohol consumption should really be done only in moderation. Also, exercising 30 minutes most days of the week and losing weight if already obese is generally suggested as an important lifestyle change. Now again, medications will also likely be prescribed alongside these lifestyle changes. And there are both first line and second line medications for treating hypertension. The first line medications are often recommended as a first, or initial form of therapy because studies have shown that they are the most effective in preventing complications from hypertension, and they're generally safe, and in most cases, pretty inexpensive. So since your blood pressure is related to the flow, or the fluid volume in your body, right, and the resistance in the vessels, these medications will target one of these two factors. And the first are thiazide diuretics. Now these guys increase the excretion of sodium and water by the kidneys, therefore they reduce your fluid volume and so, your blood pressure. You could also be prescribed calcium channel blockers, and these block the channels in your vascular smooth muscles that let calcium ions go through. So, in effect, they reduce the contractions of your blood vessels, and relax them. And this essentially makes them larger and reduces their resistance, which reduces the blood pressure, right? There's also ACE inhibitors, and these prevent the renin-angiotensin-aldosterone system from taking effect. So basically these inhibitors block the formation of angiotensin II, which is a vasoconstrictor. Since vasoconstrictors constrict your blood vessels, this will end up widening the blood vessels and basically reduce the resistance, so it'll also reduce the blood pressure. Not only that though, it'll prevent the formation of aldosterone, which reduces sodium and water retention and reduces blood volume, and so blood pressure goes down as well. And finally there's angiotensin II receptor blockers. And basically these give the same result as the ACE inhibitors but instead of blocking the formation of angiotensin II, they block the receptors that respond to angiotensin II. But if the first line choices for medications aren't effective, then the physician might choose to go to the second line choices for treating hypertension. And some of those are as follows. So first you could have the aldosterone receptor blockers which do pretty much exactly what their name suggests. They block the aldosterone receptors, and since aldosterone causes sodium and water retention, blocking these receptors will reduce your sodium and water retention and therefore reduce your blood volume, and so your blood pressure. Now renin inhibitors inhibit this enzyme called renin, which converts angiotensinogen to angiotensin I. And this prevents the eventual formation of angiotensin II and aldosterone, which just like the ACE inhibitors reduces your resistance and your blood volume. Another one might be alpha-adrenergic blockers. And these guys block the receptors that sit on your vascular smooth muscles. When these receptors are blocked, we inhibit the vasoconstriction and therefore cause the vessels to widen, which reduces your resistance. Finally you've got your central adrenergic inhibitors. And these work to prevent your brain from sending sympathetic nervous system signals that would normally cause your heart to beat faster and your blood vessels to constrict. So when we inhibit this response, your blood vessels widen, your resistance goes down, and the blood pressure goes down as well.