Hypertension Explained Clearly by MedCram.com | 2 of 2

Aug 24, 2023

Hypertension Explained Clearly by MedCram.com | 2 of 2

A clear explanation of the medications used to treat hypertension by Dr. Seheult of https://www.medcram.com/?utm_source=Y…
He details some of the less commonly used medications for hypertension including: alpha 2 agonists (clonidine), alpha blockers, nitrates, hydralazine, minoxidil, and spironolactone. This is video 2 of 2 on hypertension (HTN).

Speaker: Roger Seheult, MD
Clinical and Exam Preparation Instructor
Board Certified in Internal Medicine, Pulmonary Disease, Critical Care, and Sleep Medicine.

Recommended Audience: Health care professionals and medical students including physicians, nurse practitioners, physician assistants, nurses, respiratory therapists, EMT and paramedics, and many others. Review for USMLE, MCAT, PANCE, NCLEX, NAPLEX, NDBE, RN, RT, MD, DO, PA, NP school and board examinations.

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Produced by Kyle Allred PA-C

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Content

2.12 -> welcome to part 2 of hypertension we're going to talk about the others in

7.5 -> the last lecture in part 1 we talked about the ABC DS which was the ACE

12.269 -> inhibitor ARB for a the beta blockers for B the calcium channel blockers for C

17.91 -> and the diuretics for D I don't want to get into the other medications that we

23.13 -> use for hypertension maybe not first off the bat but further on down we'll talk

28.05 -> about them one by one and so the others is what we'll be talking about today

33.42 -> the first one we'll talk about is the alpha blockers so alpha blockers and

39.89 -> they do exactly what they say they block the alpha receptor particularly the

45.329 -> alpha 1 receptor so in the peripheral vasculature you've got two things that

50.969 -> can happen you can have vasoconstriction or you can have vasodilation and the

55.8 -> vasoconstriction is mediated by an alpha 1 receptor whereas the vasodilation is

62.539 -> mediated by the beta receptors now you should know just as a way of reminding

68.22 -> you that there's a medicine out there called dobutamine just this wave

73.92 -> reminder of if you want to have more information about this look back at our

77.46 -> septic shock lecture dobutamine is pure beta which is great for the heart is it

83.13 -> will make the heart rate go up and be more strongly contractility goes up but

89.97 -> it also stimulates the beta receptor which causes vasodilation so that's why

95.1 -> dobutamine is not really known as a vaso constrictor or vasopressor but more of a

100.71 -> positive inotrope but yet I digress so let's go back to our alpha blockers so

105.93 -> if you've got alpha receptors on this peripheral vasculature which is causing

111.229 -> vasoconstriction that's obviously going to increase your blood pressure if I

114.75 -> were to block those I wouldn't get this vasoconstriction in other words I could

119.939 -> cause vasodilation which would reduce your blood pressure so typically these

125.189 -> alpha blockers end in Osen or o s I and so process into R as a sin

133.74 -> all of these things are alpha blockers so the thing to remember about alpha

138 -> blocker the thing that they will test you is indications obviously it's used

142.89 -> as a blood pressure medication but it's never really been shown to reduce

147.87 -> mortality in congestive heart failure in myocardial infarction so really there's

153.81 -> no indication for reduction in incidence of my carbon for a congestive heart

159.42 -> failure but it does reduce blood pressure so if you just want numbers to

163.44 -> reduce blood pressure it may be effective the other thing that you

166.44 -> should remember about alpha blockers is sometimes it can actually as an

171 -> alternative also be used to prevent nightmares in PTSD so they may ask you

176.61 -> that on boards the other thing to remember probably the biggest thing to

179.97 -> remember is this thing is a side effect called first dose hypotension now the

193.26 -> thing to remember about first those hypotension is if your body is not used

196.95 -> to taking it you could really impair your body's ability to vasoconstrict and

203.7 -> this is important if for instance you're standing up if you stand up you need

207.21 -> vasoconstriction so that all of the blood doesn't rush to

210.24 -> your feet not to your head and you could pass out so that's really what you'll

214.2 -> see is first those hypotension or first those orthostatic hypotension as a

218.61 -> result of this we'd like to have the first dose taken right before bedtime so

224.37 -> take it what we call pio orally qhs that means every night before bed so that

232.14 -> most of that first dose hypotension occurs while you're already laying down

235.29 -> asleep now the other thing you should know about these alpha blockers is

238.71 -> really where they're mostly used they're not really used a lot in hypertension

242.07 -> they're usually usually used in prostatic hypertrophy or b ph benign

249.66 -> prostatic hypertrophy it's benign in terms of the fact that it's not cancer

254.49 -> however it can cause neuropathy obstruction and kidney failure if it's

259.62 -> not treated adequately and the reason why does this is for it's very same

263.669 -> principle that it causes relaxation of not only in this case the blood

268.56 -> vessels but also the smooth muscle right before the urine it comes out through

272.82 -> the urethra okay the next medication I want to talk

276.87 -> about is different class although it sounds very similar and that's the

281.07 -> alpha-2 agonist now you just said that well alpha one blockers are going to

289.5 -> reduce high blood pressure why would an alpha agonist reduce blood pressure well

293.669 -> it's because of where it is it's an alpha 2 the key there is alpha 2 and the

298.56 -> probably the best example of this one is clonidine now whereas the alpha that we

306.36 -> were talking about before works on the blood vessels the alpha 2 that we're

312.15 -> talking about those receptors are actually in the brain okay

316.59 -> there's my there's a little bit better picture of a brain okay

320.88 -> and so in the in the central brain stem there are alpha 2 receptors that are

327.57 -> actually feedback mechanisms and if you can stimulate those it'll actually ramp

332.52 -> down the sympathetic tone so if you want to know the more pathophysiological

337.68 -> explanation basically clonidine stimulates these alpha 2 receptors in

343.65 -> the brain which reduces cardiac output and peripheral vascular resistance

347.36 -> lowering blood pressure so it specifically binds to these presynaptic

351.74 -> alpha 2 receptors and so when you've got this synapse basically down here okay

360.03 -> and there's little alpha 2 receptors here when you stimulate those it

367.83 -> actually reduces the calcium in the pre synaptic cleft and it inhibits the

375.65 -> release of norepinephrine which causes low blood pressure okay so that's the

382.56 -> that's the mechanism so what do you need to know about these things well

385.889 -> clonidine is a medication because of its central action it also in addition to

391.86 -> lowering blood pressure it also can be helpful in opioid withdrawal

402.699 -> okay so that's something that it's also used for it comes it comes in two

408.259 -> different forms it can come in an oral form Pio and it can also come topically

413.419 -> as well which may be helpful in patients who can't swallow pills or patients are

417.379 -> in the intensive care unit things of that nature

420.519 -> climbing patch be aware of course that the clonidine patch is dosed q week

428.559 -> whereas the p o-- is dosed tid three times a day okay now as a result of all

436.339 -> of this you've got to remember that because it acts centrally you have a big

440.809 -> problem with withdrawal withdrawal of the

446.599 -> medication think about this on exams where you've got a patient that came in

450.949 -> with clonidine and it wasn't continued and as a result the patient becomes what

456.11 -> would they become they would become hypertensive and also tachycardic so be

460.639 -> aware of that so that's clonidine it can be it's got a number of uses it can also

466.069 -> be used for as I mentioned opioid withdrawal heroin withdrawal all those

470.899 -> sorts of things but it's also used in hypertension so just be aware of it I

474.319 -> think those are the the key points that you should know okay let's talk about

478.189 -> nitrates I'm sure you've heard of nitrates before nitrates are pretty cool

484.189 -> so let me kind of draw what we're talking about what nitrates are used

488.179 -> first of all they are used for blood pressure of course but they cause

492.229 -> vasodilation and specifically they cause more and this is the key here veno

498.559 -> dilation although they do cause vasodilation too why is this important

508.49 -> this is important because of perfusion to the myocardium let me explain

514.25 -> so what you have here is you've got myocardium okay and here you have the

523.31 -> arterial side and it's going in to feed the myocardium okay

530 -> and then where does it come out comes out to the veins

533.96 -> and it collects into the coronary sinus and it dumps into the right atrium so if

545.42 -> you want to get more oxygen profusion to the myocardium it's going to be

553.19 -> dependent on the flow to the myocardium so this myocardial tissue and that's

557.45 -> going to be the difference in pressure between the arterial supply and the

567.5 -> right atrium anything we can do to increase the pressure in the coronary

572.66 -> arteries with respect to the right atrium is going to improve myocardial

578 -> oxygen supply so when you give nitrates because it's a vino dilator because

583.79 -> remember the veins also dump in to the right atrium so if we reduce the

591.53 -> pressure in the veins it's going to reduce the pressure in the right atrium

598.82 -> and as a result of that it's going to increase the difference in the pressure

606.8 -> and that's going to give more flow to the myocardium this is the major reason

610.16 -> why nitrates are used in ischemia and cardiac ischemia so yes nitrates are

617.27 -> great at what we call preload reduction and as a result of that they can

626.3 -> increase myocardial oxygen perfusion the other thing they do is they reduce

631.55 -> afterload that's very important as well especially in patients with congestive

637.1 -> heart failure let me explain you've got the thoracic cage in that thoracic cage

644.81 -> sits your heart then you've got the aorta coming out and going down into

650.81 -> your body if you've got very very high afterload the heart has to pump against

658.43 -> that after load and as a result of that there's a there's a big back pressure

663.83 -> and so let me demonstrate that using a graph

667.67 -> here is the after load here is where the heart sits in terms of pressure in the

673.61 -> chest and here is where the aorta is and the heart has to take blood at that

682.61 -> level and pump it up to this level before it'll jecht through the aorta

686.81 -> this difference is known as afterload okay if we give somebody a nitrate yes

698.03 -> it does reduce preload but it also reduces after load and so instead of the

704.42 -> pressure in the aorta being up here it's now moved down to here that reduces

711.92 -> after load and now there's less pressure that the heart has to pump against and

716.96 -> therefore this can help in someone with congestive heart failure who has

721.1 -> pulmonary edema so we see nitrates used in myocardial infarction congestive

727.52 -> heart failure ischemia and it also reduces blood pressure the other thing I

732.74 -> should tell you is that in patients who cannot tolerate beta blockers we have

740.57 -> already said that they are key in patients with congestive heart failure

743.78 -> an alternative to beta blockers is nitrates plus hydralazine we'll talk

755.69 -> about hydrolyses next but if you can use these two together if you cannot use

760.16 -> beta blockers in congestive heart failure

762.73 -> alright so those are nitrates typically the thing you should know about nitrates

767.63 -> is that it's absolutely contraindicated in patients with right ventricular heart

773.99 -> attack or right reticular myocardial infarction or RV failure they call it so

779.27 -> don't do it in RV failure the other thing you should know is every day there

782.99 -> should be a nitrate free interval that means if you continuously use nitrates

789.68 -> the patient becomes used to it and you need to have a moment during the day

793.82 -> where the patient is not on nitrate so usually we'll do it for the greater part

798.47 -> of a day and then take it off take the patch off

801.05 -> or have a nitrate-free interval okay let's talk about hydralazine hydralazine

812.089 -> is simply a vasodilator and that's obviously going to cause the blood

819.38 -> pressure to go down so it reduces a blood pressure by causing vasodilation

824.149 -> more than it does vino dilation the the problem I guess that you should know

828.62 -> about hydralazine is it needs to be given four times a day

832.22 -> qid it can be given IV or Pio and it can't be given in combination with

837.769 -> nitrates as we mentioned in congestive heart failure patients especially in

841.04 -> african-americans seems to do pretty good the one thing that you should know

845.12 -> is that if you give it for too long you can get a lupus like condition which

855.44 -> goes away with withdrawal so it does go away they may test you for that on

863.839 -> boards if you've got a patient who's got hydralazine so the thing about

867.44 -> hydralazine is is that a vasodilator you can expect if it's going to cause

871.579 -> vasodilation what's the body going to do as a result of that it's going to see

876.62 -> that there's more volume so you might notice that your heart rate will go up

880.94 -> and you also may notice that you retain fluid so some things that you may need

889.1 -> to add to the patient who you're starting them on hydralazine is

892.55 -> something that will slow heart rate down like a beta blocker and if the retaining

898.73 -> fluid you may need to add something like a diuretic

902.56 -> okay so just be aware of that okay so let's talk about minoxidil minoxidil is

912.709 -> a vasodilator it actually hits potassium channels causing the hyper polarization

918.709 -> of the cell making it less likely to vasoconstrict

921.61 -> what you see there in minoxidil is also hair growth so it's used topically so

928.94 -> just be aware that if it's used as a blood pressure medication

934.579 -> that it can cause hair growth especially if it's used topically obviously it's

938.839 -> it's indicator for male pattern baldness but it's going to drop blood pressure I

943.459 -> find that it's very helpful in some my end-stage renal disease patients if we

951.049 -> can't get the blood pressure under better control however I would I would

954.319 -> not go to minoxidil without a nephrologist involved and just be aware

958.819 -> that minoxidil is kind of one of the last things that you would go for I

962.059 -> don't see it being tested that much just be aware of its other indication so last

965.989 -> one I want to talk about which is a nice medicine is spironolactone now spine

974.54 -> relax own is a diuretic and as such we probably should have talked about it

980.239 -> during the the first lecture that we did and if you haven't seen that lecture I

984.619 -> would recommend that you look at it the reason why I left it here is it kind of

987.739 -> stands on its own a bit as you recall the nephron the proximal convoluted

993.709 -> tubule you've got the loop of Henle collecting tube you'll remember in the

1000.699 -> distal convoluted tubule you have a sodium potassium pump where you've got

1004.029 -> sodium being reabsorbed and potassium being dumped and that would be

1009.97 -> stimulated by a hormone called aldosterone if you don't remember that

1016.449 -> look at the adrenal gland lecture that we've done i remember just go to med

1020.049 -> cram videos and you can see all the lectures that we've done but remember

1023.35 -> aldosterone is a steroid hormone secreted from the zona glomerulosa of

1027.549 -> the adrenal cortex spironolactone is a very similar-looking structure that

1032.889 -> blocks that and therefore inhibits this kind of action in the distal convoluted

1038.559 -> tubules and it's a diuretic in that case it's a potassium sparing diuretic as

1043.329 -> well so you're going to get not potassium necessarily going up

1048.51 -> potentially but not going down as much as the other diuretics would now the

1054.1 -> thing you should remember about spironolactone is that it is indicated

1057.639 -> in CHF in patients with New York Heart Association class three and four who

1065.83 -> have an ejection fraction of 35 percent or less okay so they did a

1073.72 -> trial back in 1999 that was reported in the rails trial the trial was actually

1077.86 -> discontinued early due to the unexpected benefits there was actually a 30%

1082.51 -> reduction in the risk of death and a 35% reduction in hospitalization for the

1087.25 -> patients that were receiving spironolactone and so it's it's good to

1092.56 -> use this in a patient with congestive heart failure and this kind of goes

1095.32 -> along with everything else in congestive heart failure

1098.08 -> seems as though everything that raises potassium is good so beta blockers raise

1102.64 -> potassium are good ACE inhibitors raise potassium are good spironolactone raises

1109.21 -> potassium it's just kind of a nice way to remember everything so congestive

1113.62 -> heart failure now what about the side effects

1115.36 -> obviously hyperkalemia is something you've got to watch for the other thing

1119.29 -> that they looked for and we've got to be careful of especially in these patients

1122.77 -> with congestive heart failure is the creatinine so if these patients have a

1128.2 -> crack knee that's worse than you know three three and a half things of that

1131.95 -> nature you've got to be very careful with that so acute renal failure is

1137.19 -> something you've got to watch for there's also something else that you've

1141.01 -> got to watch for and that's gynecomastia okay so if they've got gynecomastia that

1149.44 -> could be a result of the spinal a stone again probably because it is a steroid

1153.76 -> hormone blocker and so when you when you block those hormones you allow the

1159.4 -> gynecomastia to occur well now fortunately there's a new

1163.51 -> medicine that's sort of a new version of Spira lactone called EPL e r e and o and

1172.84 -> a pleura known this doesn't cause the gynecomastia the sexual side effects

1179.2 -> because it's a little bit cleaner it's specifically this a player known is

1183.82 -> specifically indicated for the reduction of cardiovascular death in patients with

1187.78 -> heart failure and congestive heart failure dysfunction within three to 14

1191.83 -> days I'm going to acute myocardial infarction so post mi with congestive

1198.07 -> heart failure in the Ephesus trial this lowered the risk of death and never

1204.519 -> needed to treat of 41 to save one life which is pretty impressive so that's

1209.35 -> something else to think about and keep in the back of your head that if you're

1212.559 -> looking for spiral lactone without the gynecomastia think of a player known

1217.48 -> it's relatively new medication but also indicator for congestive heart failure

1221.159 -> so we've talked about in a hypertension we've talked about what defines it what

1226.659 -> the indications are for treating it and again I want to emphasize that all of

1230.23 -> these things can reduce blood pressure but you want to match up what the

1233.47 -> patient's diagnosis are with the right type of medicines to use so that you can

1239.35 -> maximize the benefit and minimize the side effects and I think that's what

1245.08 -> they're going to be testing you on on the test and knowing the side effects so

1248.38 -> please go ahead and look at some of the other lectures and we will continue

1251.799 -> makes very much for joining us

1257.21 -> you

1262.55 -> you

Source: https://www.youtube.com/watch?v=NgMfZVEWQd8