HCTZ in pregnancy

[Reperfused]

For exam purposes, can we give Hydrochlorothiazide to a pregnant woman with chronic severe hypertension, or is it contraindicated?

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[zhopv10]

FA lists it as usable along with labetalol methydopa and nifedipine


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[worldbeater]

Quick hits related to this:
-Methyldopa can be used in pregnancy because of the methyl group is very large, it can't cross the placental barrier..it has a "big a-- methyl group according to KISSPharm..lol"
-the placenta in a pregnant patient has thousands of capillaries, this is what causes the blood pressure to decrease, hence why a pregnancy patient has a lower blood pressure compared a standard patient

 

[teehees]

But is it first line?

 

[Phloston]

Not at all first-line. If a pregnant woman has HTN, go-to drugs are methyldopa and labetalol. Hydralazine is used only acutely. Nifedipine is a tocolytic. I'm finishing my obgyn term in a week and have never heard/read of thiazide use in obstetrics.

 

[teehees]

Yep didn't think I had ever seen it given either. But things can change pretty quick

 

[22031 Alum]

Someone already controlled on a thiazide may continue it. It would not be initiated in pregnancy. First line is usually labetalol- aldomet has fallen out of favor except among older docs. This is real life, not sure how much help that'd be for your test.

 

[worldbeater]

Also another point about alpha methyl dopa I just came across, it is an alpha 2 agonist (makes sense, anything with a '2' causes dilation) and has a SE of coombs and hemolytic anemia

 

[Reperfused]

Thanks all of you for your inputs.
Actually I came across a question in RX in which a woman with chronic severe hypertension was on ACE-I and HCTZ. Now she was planning to get pregnant. The qs asked what would you change in the regimen and correct ans was "remove ACE-I (that's obvious)" & "increase the dose of HCTZ".

I remember coming across a statement in a previous qs in RX that mentioned HCTZ being contraindicated in pregnancy. Since FA doesn't make it clear, I just wanted to find out.

Looks like the consensus are that you would never think of initiating HCTZ in a pregnant woman, but one who's already on it, can continue.

 

[worldbeater]

Also for reference, usually thiazides are for people who have hypertension due to a high salt diet. This is usually found in canned foods (as a preservative) and for patients in poverty stricken areas. An poor african-american/black patient is a classic type of case.

 

[Phloston]

Thiazides are a first-line option for essential hypertension in someone withOUT heart failure. Dihydropyridine CCBs are also first-line in this setting. These drugs do not improve mortality in heart failure, in contrast to drugs like (but not limited to) ARBs/ACEi which do. But in the absence of heart failure, the latter won't further improve mortality unless one is diabetic. Essentially one shouldn't consider thiazides and dCCBs unless the heart is perfectly okay. I personally would never prescribe a thiazide because of their link to diabetes, unless it's a generally fit lad with calcium stones (thiazides decrease urinary calcium). There are plenty of other options out there otherwise.

 

[Phloston]

Also for reference, usually thiazides are for people who have hypertension due to a high salt diet. This is usually found in canned foods (as a preservative) and for patients in poverty stricken areas. An poor african-american/black patient is a classic type of case.

Blacks often have stiffer vessels and I'd go with a dihydropyridine CCB over a thiazide initially, in the absence of heart failure. In a black with heart failure, we'd be looking at an ACEi/ARB first, followed by a beta-blocker (bisoprolol, metoprolol-XR, carvedilol, or nebivolol, only), followed by spironolactone, followed by hydralazine and isosorbide dinitrate. I'm over-simplifying the HF Tx scheme for the sake of this thread, but the two points I want to make are 1) blacks benefit from afterload reduction (so in the absence of HF it makes no sense to choose a thiazide over a dCCB), and 2) hydralazine + isosorbide dinitrate, as a combination, yields extra mortality benefit in this group, in the setting of heart failure.

 

[W19]

Just finished pharm and the consensus was methyldopa > hydralazine ~ labetolol are the drugs that should be used to manage HTN is pregnant women. Maybe things are different in practice.

 

[W19]

Blacks often have stiffer vessels and I'd go with a dihydropyridine CCB over a thiazide initially, in the absence of heart failure. In a black with heart failure, we'd be looking at an ACEi/ARB first, followed by a beta-blocker (bisoprolol, metoprolol-XR, carvedilol, or nebivolol, only), followed by spironolactone, followed by hydralazine and isosorbide dinitrate. I'm over-simplifying the HF Tx scheme for the sake of this thread, but the two points I want to make are 1) blacks benefit from afterload reduction (so in the absence of HF it makes no sense to choose a thiazide over a dCCB), and 2) hydralazine + isosorbide dinitrate, as a combination, yields extra mortality benefit in this group, in the setting of heart failure.

I was under the impression that most physicians use thiazide like HCTZ in African Americans (AA) because of their diuretic effects (i.e their mechanism of action) since it's well known that AA use a lot of salt in their diet. But I think dCCB such as norvasc would also be good DOC to treat HTN in AA. Treating B/P sometimes varies wildly among physicians.

 

[Phloston]

I was under the impression that most physicians use thiazide like HCTZ in African Americans (AA) because of their diuretic effects (i.e their mechanism of action) since it's well known that AA use a lot of salt in their diet. But I think dCCB such as norvasc would also be good DOC to treat HTN in AA. Treating B/P sometimes varies wildly among physicians.

"AA use a lot of salt in their diet." Are we making conclusions that we know how AAs eat? Apparently they are better salt retainers though. That could be an explanation to use thiazides.

 

[W19]

"AA use a lot of salt in their diet." Are we making conclusions that we know how AAs eat? Apparently they are better salt retainers though. That could be an explanation to use thiazides.

That's probably a better way to say it!

 

[worldbeater]

I was under the impression that most physicians use thiazide like HCTZ in African Americans (AA) because of their diuretic effects (i.e their mechanism of action) since it's well known that AA use a lot of salt in their diet. But I think dCCB such as norvasc would also be good DOC to treat HTN in AA. Treating B/P sometimes varies wildly among physicians.

"AA use a lot of salt in their diet." Are we making conclusions that we know how AAs eat? Apparently they are better salt retainers though. That could be an explanation to use thiazides.

It's due to poverty, they eat a lot of canned foods that contain salt as a preservative. If you have a white/hispanic/rainbow-colored patient that lives in the same poverty stricken area, you would give the same treatment, thiazides. It's not solely based ethnicity, it's socio-economic factors. But anyways that's why your go-to for a practice question for a poor AA with hypertension is thiazides.

 

[Transposony]

Cost is also a factor since HCTZ is very cheap as you want to prescribe a drug which patient can afford (and take).

 

[deleted763299]

For what it's worth, HCTZ is listed as Pregnancy Category B according to Lexicomp. So definitely not contraindicated for pregnant patients.