March 19, 2017 by Leah
One of the major side effects of kidney disease is high blood pressure. Your kidneys are more amazing than any of us know, and when they go bad, it sets off a fantastically intricate cascade of non-optimal events. Angiostatin converting enzyme (ACE) inhibitors are the gold standard of blood pressure drugs for kidney patients because they have a preservative effect on kidney function – even reduced kidney function. They’re also poorly studied when it comes to use in breastfeeding mothers; the ones that have been studied have been shown to transfer to breastmilk and pose a risk for severe hypotension (low blood pressure) in infants, and are therefore not recommended for breastfeeding mothers.
The effect of drugs on nursing infants and/or lactation is actually a field that has not been studied in great depth in general, because the ethical implications of doing drug trials on pregnant women and nursing infants are murky, and there are a couple of different schools of thought. One is that breastmilk is so beneficial to babies that drugs that don’t seem to have much of a risk should be okay as long as the carefully-monitored infant is thriving. The other is that we just don’t know what effects drugs can have on nursing infants and mothers should avoid pharmaceuticals the way they should avoid illegal drugs and cigarettes. (A third school of thought, explained to me by a maternal-fetal medical nurse practitioner last fall, is that anything that is safe in pregnancy is safe while breastfeeding because “they use the same metabolic pathways.” This is patently untrue. The rule of thumb for breastfeeding-safe drugs is that anything that can be safely given to a young child – not a pregnant woman – can be given to the nursing mother.)
I’ve been on Labetalol, a blood pressure drug that is a “gold standard” for both pregnant and nursing women, since last fall, when I delivered M. Right before I was transferred to the high-risk maternity ward in Spokane, my local hospital gave me a dose of the stuff to get my high blood pressure down for the trip over. After I delivered the baby and my blood pressure was showing no sign of decreasing (it was actually getting worse), the doctors put me on a different drug (Nifedipine) that had very little effect on my blood pressure, but had side effects so major that I actually went to the ER because I thought I was having a cardiac episode. (I was not, and after eight hours and dosing me with radioactive stuff because I was in renal failure and couldn’t take the CT contrast dye, it was determined I was also not suffering from any blood clots.)
When M made it out of the NICU in record time (12 days for a 32 week, 5 day preemie!), I hightailed it back to my OB in my hometown and asked her for a different drug. She put me back on the Labetalol and it had a marked effect on my BP. (By which I mean I almost passed out in the pediatrician’s office during Malin’s first appointment with our pediatrician here at home, had to call my husband, and get wheeled out in a wheelchair.) She said that as long as my home BP monitoring put me in the 130s-140s over 90s, she was happy with that, and that those numbers wouldn’t indicate a need to stop breastfeeding. My numbers were mostly there, but I kept having big spikes on weekend evenings and at other random times, so she upped my dosage.
When I got to my nephrologist, he said those numbers weren’t acceptable and that we needed to keep my diastolic at or below 80 to have a positive effect on my kidney function. So my OB suggested switching my dosage to three times a day instead of two.
The upshot of all this was that I felt like a horrible person that I couldn’t get my blood pressure down. I don’t know if it’s because they always tell you to relax when they take your BP or what, but every time my blood pressure is taken I freak the heck out, and I was actually crying about it a lot of the time I checked it (twice daily) last fall, because I felt like such a complete failure of a human being. (See: having to be on pharmaceuticals while nursing a baby, being fat, having high blood pressure. Failure.)
Well. After my most recent visit, my nephrologist said, “We have a lot of room to go up on the Labetalol. Maximum dosage is 2300 mg per day.” And so we bumped me up. And guess what? My blood pressure has been running 120-125 over 75-80 since then. And I am so relieved. And I am so retroactively mad that I spent five months feeling like a terrible person and cutting my life expectancy by hardening my arteries because no one gave me that extra push to up my dosage. I am hoping that by keeping my diastolic under 80 while on a breastfeeding-friendly medication, and eating a kidney-friendly diet, I’ll be able to nurse and pump long enough to get enough milk in the freezer so that M can make it to 12-14 months and switch to cows’ milk. (Not that I have anything against formula. It’s just that I like breastfeeding, and I’m good at it, and she’s my last baby, and she was a preemie, and also I’m kind of cheap.)