Chronic kidney disease (CKD) is marked by long term, irreversible loss of function. Since it is irreversible, what we can do is only slow down its progress to end-stage renal disease (ESRD) which requires dialysis. Diabetes and high blood pressure are the most common causes of CKD. For the person having diabetes or high blood pressure, working with doctor to keep blood sugar and blood pressure under control is the best way to prevent kidney disease.

Why is good nutrition important for people with CKD?

Making healthy food choices is important to us all, but it is even more important if you have chronic kidney disease. Good nutrition gives you energy to:
– Do your daily tasks
– Prevent infection
– Build muscle
– Help maintain a healthy weight
– May keep your kidney disease from getting worsen

Will I need to control any other nutrients?

When your kidneys are not working as well as they should, waste and fluid build up in your body. Over time, the waste and extra fluid can cause heart, bone and other health problems.
You may need to balance fluids and other nutrients. There are:
– Sodium
-Phosphorus
-Potassium

SODIUM

Sodium is a mineral found in most foods. It is also found in table salt. Sodium affects blood pressure and water balance in body. If your kidneys do not work well, sodium and fluid build up in your body. This can cause high blood pressure and other problems, like swelling of ankles.

You can limit sodium by avoiding table salt and foods such as:
– Seasonings like soy sauce, sea salt, teriyaki sauce
– Most canned foods and frozen foods
– Processed meats like ham, bacon, hot dog, sausage
– Salted snack foods like chips and crackers

POTASSIUM

Potassium is a mineral found in almost all foods. Your body need some potassium to make your muscles work, but too much potassium can be dangerous. When your kidneys are not working well, your potassium level may be too high or too low.
Having too high or too low of potassium can cause muscle cramps, problems with heart beats and muscles weakness.

Use the list below to get some ideas about how to make healthy choices if you need limit potassium.

PHOSPHORUS

Phosphorus is a mineral found in almost all foods. It works with calcium and vitamin D to keep your bones healthy. Healthy kidneys keep the right amount of phosphorus in your body. When your kidneys are not working well, phosphorus can build up in your blood. Too much phosphorus in your blood can lead to weak bones that break easily.

Use the list below to get some ideas about how to make healthy choices if you need limit potassium.

FLUIDS

You need water to live, but when you have kidney disease, you may not need much water. This is because damaged kidneys do not get rid of extra fluids as well as they should. Too much fluids in your body can be dangerous. It can cause high blood pressure, swelling and heart failure. Extra fluid can also build up around your lungs and make it hard to breathe.

Depending on your stage of kidney disease, your doctor may tell you to limit fluid. To avoid dehydration, let your doctor help plan your fluids intake.

N-acetylcysteine, also known as Acetylcysteine, NAC or N-acetyl-cysteine, is a derivative of an amino acid called cysteine which is important in the production of glutathione, a potent antioxidant in human body.

Benefits of N-acetylcysteine

1. Antioxidative function

When consumed, N-acetylcysteine gets converted into L-cysteine, an amino acid that is the direct precursor to glutathione in human body. Glutathione is a potent antioxidant that can neutralize free radicals and thus protect your body cells and tissues from oxidative damage.1 Therefore, N-acetylcysteine acts as an antioxidant by replenishing the glutathione pool in body cells that becomes depleted with increased level of inflammation and oxidative stress in human body.2 This antioxidant property can help improve illnesses caused by oxidative stress, such as heart disease and infertility as well as help maintaining healthy function of immune system.3, 4, 5

2. Liver-protective function

N-acetylcysteine has been used for long as the mainstay treatment and antidote for paracetamol overdose to prevent or reduce liver damage.6 When given intravenously within 8 hours after the ingestion of paracetamol, the treatment is highly effective.6 N-acetylcysteine is also found to improve liver function in patients with non-paracetamol induced liver failure and non-alcoholic fatty liver disease thanks to its antioxidative and anti-inflammatory effect.7, 8

3. Helps relieve symptoms of respiratory condition

N-acetylcysteine is also commonly used to reduce phlegm in respiratory system. It achieves this effect by acting as mucolytic agent that reduces mucus viscosity and as a muco-regulatory agent which reduces airway mucus secretion.2 These effects, along with the anti-inflammatory and antioxidant properties of N-acetylcysteine helps to improve breathing and lung function in lung disorders such as chronic obstructive pulmonary disease, chronic bronchitis and many others.2, 9

4. Kidney-protective function

N-acetylcysteine has been speculated to be able to slow down the progress of chronic kidney disease by reducing serum creatinine and improving the structure of some of the cells in kidneys.10, 11

5. May improve mental health condition and substance use disorder

In recent years, there has been increasing interest in the use of N-acetylcysteine in helping to manage mental health conditions and substance use disorder. N-acetylcysteine has been discovered to be able to regulate the level of glutamate, an important neurotransmitter in human brain. 12 While glutamate is needed for normal brain activity, excess glutamate in brain has been found to be associated with mental illnesses such as schizophrenia or depression. 13, 14 When used in patient with substance use disorders, especially to treat young individuals addicted to cocaine and cannabis, N-acetylcysteine is effective in reducing the craving for the substances and can help abstinent individuals to prevent relapsing.13 There are also promising evidence for the use of N-acetylcysteine in treating obsessive-compulsive disorders and mood disorders, but better designed studies are required to further investigate its clinical effectiveness. 13

6. May improve fertility

N-acetylcysteine has been yielding positive results in studies that look into fertility improvement in recent years. It was found that N-acetylcysteine can be helpful in polycystic ovarian syndrome(PCOS)-related and unexplained female infertility, especially in women with high BMI, insulin resistance, and oxidative stress15 N-acetylcysteine is also discovered to have ovulation induction properties and thus can be an effective adjuvant to improves pregnancy rate in patients receiving intrauterine insemination.16 However, more well-controlled studies still need to be done to further confirm and establish the findings.

Risks and side effects of N-acetylcysteine

N-acetylcysteine on its own has very good tolerability and safety profile even at high dose.8, 13, 14 The most common side effects that are associated with it are mainly gastrointestinal disorders such as diarrhea, gastric reflux, bloating. 14, 17

However, N-acetylcysteine can potentiate the vasodilation effect of Nitroglycerin, an antianginal medication which can lead to higher incidence of side effects such as headache and severe hypotension.18, 19

People who are taking blood thinning medication, have bleeding disorders or for those who are about to undergo major surgery also need to be cautious with the use of N-acetylcysteine because N-acetylcysteine has anticoagulant and platelet-inhibiting properties, thus can increase bleeding risk.20

References

1. Ershad M, Naji A, Vearrie D. National Center for Biotechnology Information [Internet]. N Acetylcysteine. National Library of Medicine; 2023 [cited 2023Apr22]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537183/
2. Sadowska AM. N-Acetylcysteine mucolysis in the management of chronic obstructive pulmonary disease. Therapeutic Advances in Respiratory Disease. 2012;6(3):127-135. 
3. Shackebaei D, King N, Shukla B, Suleiman MS. Mechanisms underlying the cardioprotective effect of L-cysteine. Mol Cell Biochem. 2005;277(1-2):27-31.
4. Adeoye O, Olawumi J, Opeyemi A, Christiania O. Review on the role of glutathione on oxidative stress and infertility. JBRA Assist Reprod. 2018;22(1):61-66.
5. Dröge W, Breitkreutz R. Glutathione and immune function. Proc Nutr Soc. 2000;59(4):595-600.
6. Daly, F. F., Fountain, J. S., Murray, L., Graudins, A., & Buckley, N. A. (2008). Guidelines for the management of paracetamol poisoning in Australia and New Zealand-explanation and elaboration. Medical journal of Australia, 188(5), 296.
7. Dludla PV, Nkambule BB, Mazibuko-Mbeje SE, et al. N-Acetyl Cysteine Targets Hepatic Lipid Accumulation to Curb Oxidative Stress and Inflammation in NAFLD: A Comprehensive Analysis of the Literature. Antioxidants (Basel). 2020;9(12):1283. Published 2020 Dec 16.
8. Nabi T, Nabi S, Rafiq N, Shah A. Role of N-acetylcysteine treatment in non-acetaminophen-induced acute liver failure: A prospective study. Saudi J Gastroenterol. 2017;23(3):169-175.
9. Cazzola M, Calzetta L, Page C, et al. Influence of N-acetylcysteine on chronic bronchitis or COPD exacerbations: a meta-analysis. Eur Respir Rev. 2015;24(137):451-461.
10. Tian N, Rose R, Jordan S, Dwyer TM, Hughson MD, Manning RD Jr. N-acetylcysteine improves renal dysfunction, ameliorates kidney damage and decreases blood pressure in salt-sensitive hypertension. J Hypertens. 2006;24:2263–2270.
11. Ye M, Lin W, Zheng J, Lin S. N-acetylcysteine for chronic kidney disease: a systematic review and meta-analysis. Am J Transl Res. 2021;13(4):2472-2485.
12. Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. Glutamate. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10807/
13. McQueen G, Lally J, Collier T, et al. Effects of N-acetylcysteine on brain glutamate levels and resting perfusion in schizophrenia. Psychopharmacology (Berl). 2018;235(10):3045-3054. doi:10.1007/s00213-018-4997-2
14. Onaolapo AY, Onaolapo OJ. Glutamate and depression: Reflecting a deepening knowledge of the gut and brain effects of a ubiquitous molecule. World J Psychiatry. 2021;11(7):297-315.
15. Devi N, Boya C, Chhabra M, Bansal D. N-acetyl-cysteine as adjuvant therapy in female infertility: a systematic review and meta-analysis. J Basic Clin Physiol Pharmacol. 2020;32(5):899-910.
16. Bedaiwy, M.A., RezkH. Al Inany, A. and Falcone, T. (2004) “N-acetyl Cystein improves pregnancy rate in long standing unexplained infertility: A novel mechanism of ovulation induction,” Fertility and Sterility, 82.
17. Calverley P, Rogliani P, Papi A. Safety of N-Acetylcysteine at High Doses in Chronic Respiratory Diseases: A Review. Drug Saf. 2021;44(3):273-290.
18. Horowitz JD, Henry CA, Syrjanen ML, et al. Nitroglycerine/N-acetylcysteine in the management of unstable angina pectoris. Eur Heart J. 1988;9 Suppl A:95-100.
19. Ardissino D, Merlini PA, Savonitto S, et al. Effect of transdermal nitroglycerin or N-acetylcysteine, or both, in the long-term treatment of unstable angina pectoris. J Am Coll Cardiol. 1997;29(5):941-947.
20. Niemi TT, Munsterhjelm E, Pöyhiä R, Hynninen MS, Salmenperä MT. The effect of N-acetylcysteine on blood coagulation and platelet function in patients undergoing open repair of abdominal aortic aneurysm. Blood Coagul Fibrinolysis. 2006;17(1):29-34.

The kidneys are important organs that filter waste and maintain our body’s fluid balance. They also release hormones that help to regulate blood pressure at a normal level, and they play an important role in producing red blood cells in our body. Besides that, they are vital in producing the active form of vitamin D which is essential to promote strong and healthy bones.

In this article, we will discuss some common medications that will affect the kidney’s function. It’s important to understand and be aware of which medications may be harmful to the kidneys and precautions shall be taken to protect our kidneys.

Pain Relievers (Non-Steroidal Anti-Inflammatory Drugs-NSAIDs)

Some pain relievers, for example ibuprofen and naproxen, can harm the kidneys if taken frequently or in large doses. These medications relieve pain and help with inflammation.

However, it can be dangerous for those who have existing kidney problems or those who are dehydrated. Thus, we shall not take too much of pain relievers but to take them cautiously according to the dosage recommended by doctors.

Certain Antibiotics

Certain antibiotics can hurt the kidneys through a variety of mechanisms. For example, some antibiotics can block the urine flow by producing crystals that cannot be broken down. Some antibiotics have substances that can damage certain kidney cells when they are excreted from the kidneys. There are also cases where some people develop allergic reactions towards antibiotics that will adversely affect their kidneys.

When antibiotics are used for a short period of time, they are generally safe. The risk of damage to kidneys is increased when antibiotics are used in high dosage or for a prolonged period. So, bear in mind that we should only take antibiotics when prescribed by doctors and we should strictly follow their medical advices.

Diuretics/Water Pills

Diuretics, or water pills, are usually prescribed by doctors to treat high blood pressure and swelling. They work by helping to excrete extra fluid in the body. However, some diuretics, like furosemide, can affect kidney function. This is because sometimes diuretics will dehydrate the body, disturbing the balance of electrolytes in the body and the blood flow to the kidneys which can be bad for the kidneys.

Thus, it is crucial for people taking diuretics to have regular monitoring of kidney function and electrolyte levels.

Contrast Dyes

In many cases, the use of a contrast dye is necessary while carrying out diagnostic tests such as CT scans, angiograms and MRIs to help doctors see certain body tissues or blood vessels better. However, it is important to know that sometimes these dyes can be harmful to the kidneys and will either cause kidney problems, or cause problems in patients with existing kidney disease. Thus, it is important to inform doctors if you have any kidney diseases before undergoing any imaging tests involving contrast dyes.

Certain Antiviral Medications

Some antiviral medications, such as acyclovir and tenofovir, used to treat viral infections, can damage the kidneys. These medications can cause harms to the kidneys or reduce kidney function, especially when taken at high doses or for a long period. Antiviral medications can cause renal failure in many ways such as through crystal deposition in the kidneys as well as causing injury on the renal transporters and renal cells. Thus, it is imperative to have regular monitoring of kidney function if taking these antiviral medications.

Take away messages

While medications can be beneficial, it is crucial to understand the potential risks they pose to the kidneys. Be aware of which medications will affect kidney function and take necessary precautions to protect our kidneys. We shall always take medications according to the recommended dosage so as to reduce the risk of developing medication-related kidney problems and always talk to your doctors if you have any existing kidney diseases.

Reference:

1.    National Kidney Foundation. (n.d.). Pain Medicines (Analgesics). Retrieved from https://www.kidney.org/atoz/content/painmeds_analgesics

2.   American Association of Kidney Patients. (n.d.). Understanding Diuretics. Retrieved from https://aakp.org/dialysis/understanding-diuretics/

3.    Radiological Society of North America. (2020). Contrast Materials. Retrieved from https://www.radiologyinfo.org/en/info.cfm?pg=contrast-ct

4.     National Kidney Foundation. (n.d.). Common Medicines Used for People with Kidney Disease. Retrieved from https://www.kidney.org/atoz/content/medications-kidney-disease

5.     WebMD. (2022). What Meds Might Hurt My Kidneys? Retrieved from https://www.webmd.com/a-to-z-guides/medicine-hurt-kidneys

6.     National Kidney Foundation. (n.d.). Contrast Dye and the Kidneys. Retrieved from https://www.kidney.org/atoz/content/Contrast-Dye-and-Kidneys#:~:text=Contrast dyes are often used,the way they normally should.

7.     National Library of Medicine. (2005). Retrieved from https://pubmed.ncbi.nlm.nih.gov/15861345/#:~:text=Antiviral drugs cause renal failure,epithelial cells of the kidney.