How Diuretics Work

Lilly finally gets her water pill

“Doctor Mary, today is the day you’re gonna give me that water pill! I feel it in my ankle bones!”

“I think you’re right, Lilly. I suspect you feel it in your ankle bones because we sure can’t see them. Your labs look as good as I think we’re going to get them, but your ankles still look like they could use a little less fluid. I agree it’s time to start that water pill. Before we do that, is there anything else you want to talk about today?”

“Not really, Doctor Mary. I feel like I’ve been wanting this water pill for a long time and now I’m getting it and I don’t need it as bad as I thought I was going to.”

“Yes, it’s kind of a metaphor for life, isn’t it? But we’ve made great progress in getting your heart and kidneys functioning better! We’ve convinced your heart that things aren’t as bad as it thought, so it doesn’t have to pump so hard. Pumping more effectively means your kidneys are getting a better blood supply and can cleanse the blood better, so your labs are better. Now that the kidneys are receiving a better blood supply, they understand that there’s too much water in your body, and they have been eliminating some of the excess. Your ankles have gotten less swollen. You have less water in your lungs. You’re hauling around less extra fluid. All of this together is making you feel more energetic so you can do your life better! 

“Now, we’re going to add a little water pill to deal with that last bit of extra fluid you’re carrying around that’s pooling at your ankles. The pill will get your kidneys to put more water into your urine than they normally would. Here’s how that works, and why taking too much of a water pill can hurt your kidneys. 

“When blood goes through your kidneys, your kidneys take pretty much everything out of the blood but the blood cells. Then the kidneys inspect what they’ve taken out of the blood, looking for things they think should be kept. Some things, like protein, the kidneys always want to keep. So the protein gets put back into the blood as it leaves the kidneys. But most things the kidneys aim to keep at ideal levels. These are things such as water, sodium, potassium, and calcium. For example, you can eat a bunch of calcium tablets. Your stomach and intestines will then absorb all of that calcium and put it into your bloodstream. But when it gets to your kidneys, your kidneys will see that there’s more calcium in your blood than there should be. They will then put the extra calcium in your urine to get rid of it until your blood calcium level is on target.

“The way the water pill that I am prescribing for you works is that it tells the kidneys to lower their targets for sodium and potassium. Taking more sodium and potassium out of your bloodstream makes extra water go into your pee.

“In general, you want to take this pill early in the morning because if you take it too late in the day, you’ll be up all night peeing. 

“When you start it, you’ll have a few days where you pee off a bunch of extra fluid until you get to your new weight. Your ankles are a little bit swollen. You’ve still got some extra fluid on you, but we’ve done all we can to make your heart and kidneys function better. A lot of that fluid will come off in the first few days on the water pill. 

“Once you get rid of that extra water, every day you will just have to pee off as much fluid as you put in. With the water pill you’ll pee a bit more than usual for the first six hours after taking the pilll, and then a bit less than usual for the rest of the day. 

“Your ankles should get nice and slim, and I bet you lose five more pounds of water. If you combine everything we’ve done now with a low salt diet, keeping your feet up, and compression stockings, you should do really well.”

“I’ve heard for years about how bad salt is for you! I don’t eat salty foods like potato chips. I don’t even have a salt shaker.”

“That’s great! That really helps, but there’s a lot of salt in prepared foods, so if you eat out or eat canned or packaged food, you’re probably getting a lot of salt that you’re not aware of. Lunchmeats are notorious, too, for example.”

Lilly laughed. “On my Social Security check I can’t afford to go out to eat! I grow my own veggies, but I do like salami.”

“Well, one ounce of salami has at least 300mg of sodium, some has more like 500! Your whole daily intake should be around 1500mg so that one slice of salami is  20 to 30% of your whole day’s allowance for salt. A serving of cottage cheese has 800mg of sodium. That’s half a day’s allowance. There’s 400mg in a single slice of American cheese, but only 100 in a glass of milk.”

“Wow! That’s a lot for a little piece of cheese!” 

“Swiss and fresh mozzarella tend to be good options for low sodium. When you shop for food you need to be looking at the nutrition information on the package to see how much salt is in the product. It takes a while to learn about all of this. 

“In the olden days, I used to be able to refer my patients to a nutritionist who could help them out, but since Covid caused so many nutritionists to retire, I haven’t been able to find one. Sometimes if you call your insurance company, they can tell you who they will pay for you to see. They will almost always do this on the cheap, which means it will be on a video call and I bet you don’t know how to do that.”

Lilly holds up her old smartphone with its cracked screen. “Does it work on this? I only pay for a phone connection. I can’t afford no internet. Don’t know how it works anyway.”

“Well, it should, but you’d need someone to show you how and it would have to be someplace where there was free internet. It would be easier to have someone who knows what they’re doing just do everything for you. I don’t remember; does Joann have internet?”

“She has something for her grandkids cuz they spend a lot of time with her. I could ask her. She’s always talking about how her ten-year-old grandson knows how to do everything on the internet. Maybe he could help me.”

“Another thing you could do is to read up on low-salt diets. You could try the library.”

Lilly replied, “Now, there’s something I could do! I should have thought of that! I go there to get DVDs to watch. Our librarians are really helpful and friendly. Since I’m retired I go there when they’re not busy and we chat some, even though you’re not supposed to in libraries. I’m sure they’ll find me something, even if they have to get it from another library.”

“That’s a great idea.”

Lilly was quiet for a moment, and then changed the subject, “Now, I’m not slapping my kidneys around with this pill am I? I don’t want to do that.”

“No, this is a small dose. It should be just fine, and to be sure that it is, I will ask you to check your labs in about a week to make sure your kidneys aren’t unhappy with it. Also, this is not the same kind of water pill I prescribed for you last year, when your heart was in better shape and all we were trying to do was to lower your blood pressure. While that pill took water out of you, the main effect it had was to lower your blood pressure. This new water pill gets water out of you while only lowering your blood pressure a little bit. 

“Now, as for your other question. The other water pill I gave you was for when your blood pressure was high. It was almost like its main job was lowering your blood pressure and the water part was just a happy side benefit. This one is more for getting rid of fluid and it may well lower your blood pressure a little bit, but that’s not its main job. 

“And - not to keep coming back to this - but when you were taking four of those blood pressure pills that also lowered your water, not only were you forcing your kidneys to get rid of more water than they should be, you were pushing your blood pressure lower which then made your heart to work harder. But your heart was already working as hard as it could, so you ended up hurting your heart and your kidneys. Fortunately, this did not go on long enough to cause permanent damage to your kidneys or your heart, and to make sure that doesn’t happen is one of the reasons we have you get your labs done regularly.

“You see these two numbers here?” I show her her latest set of kidney labs. “This one and this one, you can see how they’ve gone up and down together? Well, probably what will happen when we add a little water pill is this one will stay the same,” I point at the creatinine, “and this one will go up a little bit.” I point at the BUN. That’s how we know we’re in the sweet spot, where your kidneys are not unhappy with what they’re being told to do, or at least they’re not too unhappy.”

We both stare at the computer screen for a moment, then I continue, “It’s like working together as a team. We’ve told your heart to get more blood to your kidneys so they can work better. We’re now asking the kidneys to be a bit less comfortable so the rest of the team can work better.”

Lilly frowns a bit, “I just get worried whenever anyone says you have to be part of a team because that usually means someone else is getting something they want from me, and I’m getting the short end of the stick. Like sure, I’ll work overtime so the boss can take care of her sick mother-in-law and then when she comes back, I get fired. Team usually means someone wants something from me, then they’re gonna take advantage of me or get rid of me. I can’t do that to parts of my body. I’m not that kind of person.”

I had thought my teamwork explanation would play well with Lilly, but her response took me by surprise. Now, it was my turn to sit quietly and think. “Well, your kidneys will tell us if they’re not happy by changing their lab values, like they did before.”

“I know and I feel so bad that I didn’t understand. I thought if two of them other water pills was good, four would probably be better.”

“That’s why we check your labs. Your kidneys will tell us what they’re thinking as long as we keep checking your labs. They won’t – they can’t – hide their feelings. 

“In addition to those lab numbers, I’m depending on you to tell me about how you are doing overall: how are you climbing the stairs, are you able to lie down flat at night, stuff like that. Then we put all of that together to make our plan for how to make you overall as well as possible. That can mean making things harder for some of your healthier organs so that things are easier for your less healthy organs. Each part of your body depends on the other parts.”

Lilly replies, “One thing I’ve learned in life is that I’ve got to depend on myself. Can’t trust nobody except my dogs and my friend Joann. My church family is good to a point, but I’ve seen them turn on somebody for no good reason. Gotta look out for yourself, Doctor Mary. Can’t trust nobody else to.”

“I don’t know, Lilly. Sometimes you do have to trust other people, maybe just a little bit. Very few of us, maybe none, spend our entire lives able to take care of ourselves completely. We pretty much all need help at the beginning and end, at least. Hopefully, we have a lot of time in the middle to figure out who we can trust. I hope you feel you can trust me, and I hope that I demonstrate that I deserve that trust.”

Lilly begrudgingly replies, “Yeah, you’ve done okay so far, Doctor Mary, you’re all right. Joann was right. You’re not like them doctors who act all bossy, pushing their pills, making it sound like you’re gonna die in ten minutes if you don’t follow their commands.” 

I know Lilly does not trust easily. This shred of trust in me is precious, and she is telling me how I can screw it up: make her feel like I’m pushing her around, not just with pills, but with anything I say or do. 

Trust is a key priority for a successful relationship. I would like to be able to talk with her about the very real risks to her of not fully treating her heart failure. Roughly half of the people diagnosed with heart failure are dead within five years. But I’m in a Catch-22 here. If I tell Lilly about how poor her prognosis is, she’s going to interpret it as me pushing her around, telling her she’s going to die in ten minutes. Then she’s going to lose trust in me, and I can’t do my job as a doctor. If I don’t tell Lilly, then I’m not doing my job as a doctor. I’m failing to allow Lilly to take full advantage of all the things that would help keep her alive. But I’m concerned that even telling her this might cause her to reject all treatment from me, but I feel I’m not doing a good job of informed consent with her without having this conversation. 

I’ve focused Lilly’s treatment so far on things I can do for her that she’ll readily be able to feel and see benefits from. I have other treatments that I’d like to talk to her about: things that will help her to live longer. While we doctors know these things work, because clinical trials have been done on them to prove they work, Lilly can’t assess them herself. They’re just more pills to take, more doctor visits, more co-pays to make from her limited budget. She’ll never be able to judge them for herself - and Lilly is about the only person whose judgment of things Lilly trusts. 

Yet, how can she say no to something whose benefit has not been explained to her? My education and my valuing patient autonomy scream out “No! You must tell her more.” At the same time, I recognize that Lilly has repeatedly demonstrated that she has very little trust in doctors, and what precious little she has is in my hands. If I do anything to lose that trust, Lilly is unlikely to trust any doctor ever again.

“Thank you for that, Lilly. I will do my best to deserve your trust.”

“Well, like I used to tell my kids, nothing worthwhile comes easy.” 

Lilly’s mood has shifted a lot from the beginning of our appointment. She seemed to be looking forward to getting her water pill, but somehow my mentioning teamwork triggered some unpleasant memories for her. Lilly appears to be one of those people who just aren’t team players, and trying to make them into team players backfires. Good healthcare, however, is a team effort between patient and doctor. So in our relationship, all of the teamwork is going to depend upon me.

“Anyway, are we done with this water pill thing?”

“Yes. I’ll put the orders in for those labs. Let’s give you a few days on the water pills and then we check your labs and see you on, say, Tuesday. Of course, if you don’t feel well before then, give us a call. If all goes according to plan on Tuesday, you can have three months off after that without coming in.”

“That would be good. I’m getting tired of the art in your waiting room.”

“I’ll let our office manager know,” I smiled, “Remember: wear your socks and avoid salt. Your limit is 1500mg. Let me know how you do at the library.”

With Lilly, so much about what I normally talk about with patients ends up left unsaid and ambiguous. Yet, I didn’t see that I could do anything with her other than what I was doing. I hoped it was enough. And not too much.

This poster is for sale at allposters.com should you like it more than Lilly does.

* As always, Lilly is a patient amalgam and any resemblance to a real patient is accidental. The statistic, however, is all too real.

**Nothing in here should be taken as personal medical advice. If you want to know more about your heart or kidneys or how to care for them, please call your doctor.