Three questions about renal function asked by PTs and OTs

It was the moment I had finished the conference and was about to head home.
That was when it happened.

“HONO-san, does renal function have anything to do with exercise?”

A fellow PT called out to me.
I was very happy that they asked.
Because until then, I had never received a question that directly linked 'renal function' to rehabilitation.

This article is a verbatim transcript of that conversation.

And it is also a story about what I still feel is the 'fascinating aspect of a convalescent rehabilitation ward,' even now, after working as a pharmacist for over 20 years.

Why pharmacists care about renal function

When that PT approached me,
I was just reviewing a patient's medication history.

“HONO-san, do you have a moment? Does renal function have anything to do with rehabilitation?”

For a moment, I wondered, 'Where should I even start?'

The reason pharmacists care about renal function is simple.
Because most drugs leave the body through the kidneys.that is why.

Once ingested, drugs dissolve into the blood, circulate throughout the body, and are eventually excreted as urine. The kidneys act as the 'exit' for this process. Therefore, when renal function declines, drugs are not excreted and instead accumulate inside the body.

What happens when they accumulate?

For example, with sleeping pills or anti-anxiety medication,
over-sedationoccurs.

This is a state of 'feeling somewhat dazed' or 'feeling unsteady.'

With painkillers,
it can lead to gastrointestinal issues or further deterioration of renal function.
Depending on the antibiotic, some can affect hearing or cause muscle spasms.

And above all,the risk of falling increases.

When I explained it this way,
I felt the PT's expression change slightly.
I think that with the word 'falling,'
it suddenly became a personal matter for them.

“...Does that happen during rehabilitation too?”

“Yes, it does. When medication is too effective, it can manifest as unsteadiness during walking practice or delayed reactions. Especially if renal function has declined and the medication dosage hasn't been adjusted.”

Three questions frequently asked in a convalescent rehabilitation ward

Following that day's conversation, not only PTs, but also OTs and STs began to reach out to me little by little. The content of their questions generally boils down to three patterns.

Question 1: "Can kidney function worsen during rehabilitation?"

This is a question I was asked by an OT.
"Can rehabilitation itself put a strain on the kidneys?"

When I received this question,
I hesitated on how to answer.
Although the term "rhabdomyolysis" came to mind, I paused for a moment, wondering "how far and how should I explain this?"

Even now,
there are moments like this where I have to organize my thoughts while speaking.

"It is possible. For example, when the intensity of rehabilitation is suddenly increased, a large amount of muscle can be broken down. This is called rhabdomyolysis, and the fragments of broken muscle can clog the kidneys and reduce their function. It's rare, though."

"Wait, muscle breaking down...?"

"Muscle soreness after exercise is also a state where muscle fibers are microscopically damaged, but this is when destruction occurs at a level incomparable to that. That's why we need to be cautious about suddenly applying rapid loads—"

"I've heard that urine turns red; is that it?"

"Yes, exactly. Cola-colored urine is a typical sign."

Then I added,
"Also, dehydration hits the kidneys directly. If hydration is insufficient during rehabilitation, the blood becomes concentrated and blood flow to the kidneys drops. Special care is also needed before and after contrast-enhanced examinations—" as I was saying this, the OT confirmed, "Contrast media is what you use for CT scans and such, right?"

I like those kinds of exchanges,
which might be why I work in convalescent rehabilitation.

Question 2: "Should I lower the rehabilitation intensity for patients with low eGFR?"

This is a question I was asked again later
by the same PT.

"I have a patient with an eGFR in the 30s; should I lower the rehabilitation intensity?"

Looking at the number alone, it is certainly low.
But I
answer, "You can't decide based on the number alone."

"The eGFR number is an important indicator, but it's dangerous to determine intensity based on that alone. You have to consider it as a set: what medications the person is currently taking, what their nutritional status is, and whether they are showing symptoms."

"What kind of symptoms?"

"If they have severe fatigue, leg cramps, shortness of breath, loss of appetite, or swelling... if those things overlap, I suspect that the kidney condition might be worse than the numbers suggest. Conversely, if the eGFR is low but there are few subjective symptoms and nutritional status is maintained, rehabilitation can sometimes be progressed cautiously."

"In other words, you mean to look at the numbers and symptoms together."

That's right. While I always confirm with the attending physician, from a pharmacological perspective, I go into conferences with information like, 'This patient is on many renally excreted drugs, so a dose reduction might be necessary,' or 'This patient is taking medication that increases the risk of dehydration.'

The PT thought for a moment before speaking.
'We didn't have that perspective.'
It makes me truly happy to hear them say that.

Question 3: 'This patient is edematous, is it okay to restrict their fluid intake?'

This is one of the 'scariest' questions
I have received from a nurse.

'Their legs are swollen and they have heart failure, so should I restrict their fluid intake?'

At first glance, it seems like 'edema = too much fluid = should restrict.' But you can't judge based on that alone.

'The heart and kidneys are connected. When heart function declines, blood flow to the kidneys decreases, and the kidneys try to retain water. This mechanism is called cardiorenal syndrome. Therefore, the appropriate response changes completely depending on whether the cause of the edema is the kidneys, the heart, or hypoalbuminemia due to malnutrition.'

'Can't we just use diuretics?'

'Diuretics certainly reduce edema, but if used too much, they lead to dehydration, which in turn puts a burden on the kidneys. The balance of electrolytes—sodium and potassium—is also disrupted. That is why it is necessary to monitor the dosage and effects of diuretics and act while confirming 'where the patient is currently at.'

The nurse frowned slightly.

'That's quite complicated.'

'It is complicated. But I think that is exactly whywe think about it as a multidisciplinary team. Nurses are the ones who notice the edema, and PTs and OTs are the ones who see the changes during rehabilitation. I believe my role as a pharmacist is to add the perspective of medication to that.'

When I speak at multidisciplinary conferences

What I always check before a conference is
the recent trend in renal function.
Whether the eGFR is up or down this week.
I look at the flow, not just a single numerical value.
Then, I checkwhether any renally excreted drugs are being used and if the dosage is appropriate.

The timing for talking about renal function is
often 'when there is a change in the patient's behavior.'

'They've been acting a bit dazed lately'
'They've been stumbling more often during rehab'
When reports like these come up,
I speak up as it is a time to suspect the influence of medication.

Even if the numbers haven't changed,
I sometimes suggest, 'It might be better to adjust this medication according to their renal function.'

I don't always have all the answers ready to go every time.
There are still times when I say, 'I'll take this back and check,' and look it up later.
But I think that's fine.
Because I believe that showing that attitude is the first step toward getting people to think, 'Let's ask the pharmacist.'

What is important is not having the answer, but showing the attitude of wanting to think about it together, is what I have learned over these 20 years.

There is only one thing I do to make PTs and OTs think, 'Let's ask the pharmacist.'

Being in a place where it is easy to be approached.

Stopping for a moment after the conference.
In that sense, I think having a pharmacist stationed on the ward is a very good environment.

If PTs and OTs are reading this, please let me say this.
When you think, 'I wonder if it's okay to ask a pharmacist,' I want you to value that feeling.
That 'just asking a quick question' might prevent one patient fall.

Starting in June, I will begin a series called 'From the Front Lines of Rehabilitation Pharmacy'.
I intend to write about what I see from the convalescent ward, including medication adjustment lists based on renal function, actual interactions during conferences, and the reality of multidisciplinary collaboration.
This article is episode 0. I would be happy if you read the continuation.

Conclusion

'HONO-san, please teach me again sometime.'
When a PT said that to me,
I felt glad to be a pharmacist.

Talk about kidneys is difficult.
But depending on how you convey it, you can become a partner to other professions.
I believe that is the interesting part of being a pharmacist in a convalescent ward.

At your workplace, have you ever asked a pharmacist about renal function?
Whether it's 'I didn't know I could ask that' or 'I've been asked something like this,' any feedback is welcome.
Please let me know in the comments.

▼ Click here for articles related to 'Rehabilitation Pharmacy' that I conduct together with other professions in the convalescent ward.