IV hydralazine and "PRNs for high BP" on inpatients

[cbrons]

This is something that literally makes my blood boil. In my hospital, the admission order set includes IV labatolol and hydralazine for SBP >160 and 170, respectively. Is there any one else who finds the general practice of aggressive treatment of asymptomatic hypertension in inpatients to be incredibly dangerous and idiotic?

Also, is there any instance that you can think of where IV hydralazine is an acceptable drug to use in adult human beings? It has an immediate onset of action, cause reflex tachycardia, and lasts for like 20 minutes. Not to mention the fact that it is extraordinarily unpredictable.

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[IlDestriero]

It's great for intraop hypertension from prolonged tourniquet time, a vasoactive drip of some sort would probably be better, but I don't have that in my cart. You have to be cautious though as the 1/2 life is several hours not minutes and it takes several minutes to cause the desired BP drop.


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Il Destriero

 

[AdmiralChz]

Labetalol's onset is near-immediate, hydralazine is relatively delayed 5-10 minutes at the most (in the operating room, this can seem like an eternity). While labetalol is much easier titrated, it can be poorly tolerated in patients with bradycardia and cardiomyopathies.

While hydralazine usually isn't my first-line anti-hypertensive, it's one of the first ones in my tool box if I'm struggling and it's important to maintain lower pressure in a given patient population. One can argue for nicardipine but that's not as easily titratable either and isn't very practical for acute, intraoperative management.

I suspect we'll see more of clevidipine going forward, an ultra-fast acting arteriolar vasodilator lending itself to rapid titratability.

 

[NotAProgDirector]

I agree, it's dumb. Upon taking over a service, I d/c all of these orders. Unfortunately, especially in the step down unit, I get pages asking me what we are going to do about an SBP of 172. My answer is "nothing", but then I spend a few minutes explaining that we wouldn't admit a patient to the hospital for a BP like that.

So far, I haven't heard of anything bad coming from PRN labetalol or hydralazine.

 

[Rendar5]

The reason to use hydralazine is if the patient already has a HR down to about 60, and I need to drop the SBP under 180mmHg so the floor nurse doesn't try and throw a fit about taking the patient from the ED. It's just to get a good number for someone else (not for me). If the patient is asymptomatic I don't treat just to treat. And if they're actually malignant htn (I don't believe in htn urgency), then I prefer a drip that's titratable (not labetalol either).

 

[surgonc2017]

IV hydralazine is to to treat the nurse not the patient. I put in prn hydralazine for low HR and labetolol for high HR and now I don't get woken up by pages all night on my service of 50 hypertensive nonogenarians asking for antihypertensives.


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[Another Second Opinion]

This is something that literally makes my blood boil. In my hospital, the admission order set includes IV labatolol and hydralazine for SBP >160 and 170, respectively. Is there any one else who finds the general practice of aggressive treatment of asymptomatic hypertension in inpatients to be incredibly dangerous and idiotic?

Also, is there any instance that you can think of where IV hydralazine is an acceptable drug to use in adult human beings? It has an immediate onset of action, cause reflex tachycardia, and lasts for like 20 minutes. Not to mention the fact that it is extraordinarily unpredictable.

Good questions. I agree that treating SBP <170mmHg with IV meds is aggressive. But I would say that it is a great drug when someone's BP acutely jumps >190mm Hg and they have a lower pulse rate. It's not a long term solution, but gets your BP into an acceptable range while you treat other issues- pain, delirium, etc.

 

[cbrons]

Good questions. I agree that treating SBP <170mmHg with IV meds is aggressive. But I would say that it is a great drug when someone's BP acutely jumps >190mm Hg and they have a lower pulse rate. It's not a long term solution, but gets your BP into an acceptable range while you treat other issues- pain, delirium, etc.

Why do you need to treat asymptomatic systolic P of 190? Why not just address the underlying issue, e.g. pain.

I've seen 3 instances where IV hydralazine has lowered someone from above 180 to sub-100s even using the lowest dose. That is far more dangerous than leaving them alone.

 

[Rendar5]

Why do you need to treat asymptomatic systolic P of 190? Why not just address the underlying issue, e.g. pain.

I've seen 3 instances where IV hydralazine has lowered someone from above 180 to sub-100s even using the lowest dose. That is far more dangerous than leaving them alone.

You don't need to treat asymptomatic htn immediately to help the patient. Hopefully no one is arguing that. (and hopefully this myth of acutely dangerous asymptomatic htn starts going by the wayside, but look how long it's take for shellfish/iodine to go away. The data on htn is like 15yr old and it takes 20-25years for medical myths to go by the wayside. I still get pushback on giving ceftriaxone to pcn-allergic patients)

That said I've never seen a catastrophic bp drop with small doses but I always do multiple things before it comes to any dosing such as repeat bp multiple times on different extremities make sure it's the right size cuff, treat underlying anxiety and pain, etc., so the only thing left is BP (either malignant [though that normalllly gets drips], symptomatic, preventing tpa, or a road block to getting the patient to the floor).

 

[Another Second Opinion]

Why do you need to treat asymptomatic systolic P of 190? Why not just address the underlying issue, e.g. pain.

I've seen 3 instances where IV hydralazine has lowered someone from above 180 to sub-100s even using the lowest dose. That is far more dangerous than leaving them alone.

I see your point, but if I have an older patient with CHF or significant CAD, I'm not going to let the heart work that hard while I figure out the cause. I'll get the BP lowered, then go from there. I use hydrazine all the time, never once had someone bottom out from a standard dose. I usually start with 10mg and titrate from there.

 

[cbrons]

I see your point, but if I have an older patient with CHF or significant CAD, I'm not going to let the heart work that hard while I figure out the cause. I'll get the BP lowered, then go from there. I use hydrazine all the time, never once had someone bottom out from a standard dose. I usually start with 10mg and titrate from there.

So why would you use a drug that increases myocardial work from reflex tachycardia?

 

[flagyladams]

Hydralazine is a great drug to lower sbp in acute stroke for tpa administration

 

[Another Second Opinion]

So why would you use a drug that increases myocardial work from reflex tachycardia?

I feel like you're trying to argue because you don't like Hydralazine, which is fine, you don't need to use it.

If someone had a pulse in the 50's or 60's with a poor heart and severe hypertension, I would give hydralazine, accepting that there may be some reflexive tachycardia. Severe aortic/mitral regurgitation would benefit from a faster heart rate and lower BP anyway.

The point is you have to use your clinical judgement. You can't make a blanket statement that Hydralazine is a bad drug and should never be used. Would I use it on a guy sitting in the ED with high BP and completely asymptomatic? No. Would I use it if the BP spiked and there was a new graft over the carotid or fresh thyroidectomy? Probably, if the clinical scenario justified it.

 

[AdmiralChz]

So why would you use a drug that increases myocardial work from reflex tachycardia?

I see this concern, but for the situations described above it shouldn't be too much of an issue. If the HR is 40s to 50s or even 60s, I have yet to see profound reflex tachycardia above 80. I have seen some hypotension from midlevels and interns ordering some aggressive doses, but even then the tachycardia wasn't all that bad.

 

[flasheroonie]

So why would you use a drug that increases myocardial work from reflex tachycardia?

On the floors, I've only ever used hydralazine as a last resort. In any case, I'd want to know WHY their BP is so high. Are they in pain? Are they agitated? Are they having sex with a visitor (actually happened with one of my patients while on telemetry during residency)?


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[Another Second Opinion]

Are they having sex with a visitor (actually happened with one of my patients while on telemetry during residency)?


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Maybe a replacement for the treadmill stress test?