Medical News Today: Passing kidney stones: 2-drug combo may relieve pain

Researchers from the Massachusetts Institute of Technology (MIT), in Cambridge, may have found a combination of drugs that can relieve the pain of passing a kidney stone. They performed their study in pigs.

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New research may help alleviate kidney stone pain.

Anyone who has ever passed a kidney stone knows that it can be a painful experience.
Every year, over half a million people in the United States experience this pain, and about 1 in 10 people will have a kidney stone at some point.
Kidney stones usually leave the body without a doctor's intervention, but this can be a slow, painful process.

However, the experience may soon be a thing of the past, according to a new study appearing in Nature Biomedical Engineering.

The team behind this research has found a combination of two drugs that can relax the walls of porcine ureters. Potentially, these medications could prevent kidney stones from causing such severe pain in humans.

The problem with kidney stones

Prof. Michael Cima, the study's senior author, notes, "We think this could significantly impact kidney stone disease, which affects millions of people."
Prof. Cima works with MIT's Department of Materials Science and Engineering and the school's Koch Institute for Integrative Cancer Research.

The stones form when urine that usually washes crystals from the kidneys contains too much solid waste and not enough liquid to get the job done.

These crystals clump together, forming stones that painfully force their way down the narrow ureter, causing cramps and inflammation. Most pass within a few weeks, though the discomfort can be consistent and severe. Occasionally, large stones require surgical removal.

Because the Food and Drug Administration (FDA) have yet to approve the use of any oral medications to widen the ureter and help the stones pass, doctors often simply prescribe pain relief medications.

Previously, other researchers have trialed ureter relaxants, but the drugs have not proved conclusively helpful.

About the new study

The study's lead author is Christopher Lee, Ph.D., of the Harvard-MIT Health Sciences and Technology joint department. He describes the motivation for the new research:

"If you look at how kidney stones are treated today, it hasn't really changed since about 1980, and there's a pretty substantial amount of evidence that the drugs given don't work very well. The volume of how many people this could potentially help is really exciting."

Christopher Lee, Ph.D.

Prof. Cima and Dr. Brian Eisner — the latter a study co-author and urologist that specializes in kidney stones — became interested in finding an effective approach. Lee soon joined their inquiry.

They began by identifying 18 drugs that doctors typically use to treat issues such as hypertension and glaucoma.

Since they suspected that medications directly administered to the ureter might be more effective, they exposed human ureteral cells, grown in lab dishes, to the 18 drug candidates in order to determine the extent to which the medications could relax ureteral tissue.

However, reports Prof. Cima, "We found several drugs that had the effect that we expected, and in every case, we found that the concentrations required to be effective were more than would be safe if given systemically."

2 drugs are better than one

The researchers further analyzed their results, looking for a two-drug combination that might be effective at lower, safer dosages. Eventually, they found two top-performing drugs that could produce even more positive results when administered together.

One of the drugs, nifedipine, is a calcium channel blocker that doctors can use to treat high blood pressure. The other is a Rho kinase inhibitor, which can treat glaucoma.

The team then delivered various dosages of the mixture via a tubular tool called a cystoscope to ureters that had been removed from pigs.

To gauge their effectiveness at relaxing the ureter tissue, the researchers tracked the frequency and length of contractions, or cramps, associated with passing the stones.

Later tests in live, sedated pigs revealed that the drug combination could nearly eliminate these contractions.

In addition, subsequent tests found no traces of either drug in the bloodstream. The implication is that this medication remains in the ureter, reducing the risk of systemic side effects.

The researchers hope to conduct further research and development, eventually leading to trials in humans.

Original Article

Medical News Today: What you need to know about kidney failure

The kidneys filter the blood and remove extra water and waste from the body. When something causes the kidneys to work less efficiently, it can lead to kidney failure.

Various conditions can cause the kidneys to work less efficiently. This prevents the removal of waste, and when this happens, it can give rise to kidney failure.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), kidney failure occurs when a person has less than 15% kidney function.

In this article, learn about the different types of kidney failure, as well as the stages, symptoms, causes, treatment options, and prevention methods.


There are two types of kidney failure: acute and chronic. The sections below will discuss these in more detail.


Acute kidney failure (AKF), otherwise known as acute kidney injury or acute renal failure, comes on suddenly, typically within a few hours or days.

It may occur due to trauma to the kidney or decreased blood flow in the area. It can also occur due to a blockage, such as a kidney stone, or very high blood pressure.

According to the Urology Care Foundation, kidney function often returns with AKF treatment.


According to the NIDDK, chronic kidney disease (CKD), also known as chronic renal failure or chronic renal disease, may affect more than 30 million people in the United States.

When a condition is chronic, it means that it occurs over a long period of time. Damage to the kidneys occurs gradually and can eventually lead to kidney failure.


According to the National Kidney Foundation, there are five stages of kidney disease:

a infographic showing the stages of kidney disease


Symptoms vary greatly depending on whether a person has acute or chronic kidney failure and what stage it is at.

Although symptoms can start at any stage of kidney disease, they typically begin in the later stages.

Typical symptoms of kidney failure include:

  • swelling of the feet and legs due to fluid retention
  • trouble sleeping
  • muscle cramps
  • numbness or tingling in the fingers or toes
  • loss of appetite
  • metallic taste in the mouth

By stage 5, symptoms may also include:

  • headache
  • producing little or no urine
  • trouble breathing
  • nausea and vomiting
  • changes to skin color


In order to diagnose kidney disease, a health professional can perform a blood test or urine test.

A blood test measures the creatinine level. If there is more creatinine in the blood, the kidneys may not be functioning as well.

A urine test checks for albumin, a protein that may pass through the urine if the kidneys are damaged.

Causes and risk factors

Various types of injuries and diseases can give rise to kidney failure. Certain conditions might cause AKF, while others may lead to CKD.

Common causes of AKF include:

  • low blood flow to the kidneys
  • inflammation
  • sudden high blood pressure
  • blockages, sometimes due to kidney stones

Common causes of CKD include:

  • elevated blood sugar
  • high blood pressure
  • kidney infections
  • polycystic kidney disease

Although anyone can experience kidney failure, certain factors may increase a person's risk of developing the condition.

Some risk factors include:


When the kidneys do not function properly, it has a significant impact on other organs in the body. This means that as kidney failure progresses, other complications can also develop.

Possible complications include:

  • heart disease
  • high blood pressure
  • bone loss
  • anemia


Treatment for kidney failure often includes the following options:


Dialysis involves using a dialyzer machine, which performs the healthy function of the kidneys. The machine filters water and waste from the blood.

A type of dialysis called peritoneal dialysis uses the lining of a person's abdomen to filter the blood.

After a dialysis nurse has trained them for 1–2 weeks, a person can perform this dialysis at home, work, or when traveling.

Dialysis does not cure kidney failure, but it may help improve a person's quality of life.

Kidney transplant

If a person's kidney function is 20% or less, they may be eligible for a kidney transplant. Donated kidneys can come from a living person or a deceased donor.

After receiving the new kidney, the person will need to take medication to make sure that the body does not reject it.

The transplant matching process is lengthy, and not everyone is eligible for a transplant.

Clinical trials

Clinical trials are also an option for some people with CKD.

Various trials are available that evaluate medications, treatments, and protocols for kidney failure.

Treatment plans

A treatment plan will be comprehensive and may include:

  • carefully self-monitoring to watch for signs of worsening kidney function
  • following a renal diet, as prescribed by a doctor or nutritionist
  • limiting or eliminating alcohol, which causes the kidneys to work harder
  • getting plenty of rest
  • exercising

A person may also need treatment for the complications of kidney disease. For example, to treat anemia, a doctor may prescribe iron, vitamin B, or folic acid supplements.

Coping and support

People with CKD may need emotional support. It may be helpful to talk about feelings with a friend or family member.

Getting professional help from a dialysis unit social worker or counselor may also be useful to work through emotions.

A person with kidney failure should find ways to relax, stay active, and continue participating in everyday life to aid their emotional well-being.


Taking certain steps may decrease a person's risk of developing kidney failure.

Additional preventive measures include:

  • treating urinary tract infections to prevent kidney damage
  • limiting alcohol intake
  • stopping smoking
  • eating a healthful diet
  • maintaining a healthy weight
  • exercising for at least 30 minutes on most days of the week

When to see a doctor

If a person experiences any symptoms of kidney failure, they should see their doctor.

The sooner treatment for kidney failure starts, the better the outcome. Getting treatment for AKF may also prevent the condition from progressing to CKD.


The outlook for kidney failure varies depending on whether the condition is chronic or acute.

AKF usually responds well to treatment, and kidney function often returns. CKD usually does not improve, but it is manageable with treatments such as dialysis.

Undergoing a kidney transplant to treat CKD may also improve the outlook.


Kidney failure occurs when the kidneys can no longer adequately filter blood and remove waste from the body.

The condition can occur suddenly or develop slowly over time. Kidney failure can lead to various complications, including anemia, bone loss, and heart disease.

Usually, treatment involves dialysis and making lifestyle modifications.

Original Article