One of my Gitelman patients (whom I kidding, “one of my Gitelman patients”, how about “my only Gitelman patient”) finally got pregnant. We had been managing her with amiloride and a truck load of oral potassium and magnesium supplements. I was shocked to find that amiloride is acceptable in pregnancy with a track record of successful births. Prior to starting amiloride the patient was taking twenty-eight 20 mEq pills of KCl a day. She abandoned her prior nephrologists when she was told to further increase her potassium pills.
We are now using magnesium sulfate infusions 4 grams twice a week to keep her magnesium north of zero. She was able to keep her magnesium around 1.4 with oral supplements and amiloride prior to being pregnant but now, despite 8 grams of weekly IV magnesium her magnesium is sitting around 1.1. This probably represents one of downsides of the up-regulated GFR of pregnancy.
Interestingly, she saw her labs and saw that her sodium was 132. Modest hyponatremia is a normal finding in pregnancy, so she decided to increase her dietary sodium intake. Bad move, increased renal sodium loads increases renal magnesium losses. Her serum mag fell 30% to 0.8.