July 29th 2025
By Ari Parker
Learn the common causes of low sodium in older adults, including medications, chronic conditions, and dietary factors, plus when to seek medical care.
By Ari Parker
Low sodium level in the blood, also known as hyponatremia, is common in seniors. Possible causes for low sodium levels in the elderly include age-related kidney changes, use of certain medications, and underlying medical issues like heart and kidney disease.
Because low sodium levels are linked to confusion and an increased risk of falls, it’s important to seek treatment. Severe hyponatremia in seniors can also be life-threatening and requires immediate medical attention.
Low sodium levels in the elderly can result from medications such as diuretics, antidepressants, and antiseizure drugs.
Some health issues can increase your risk of low sodium levels. These include kidney, liver, and heart disease.
Symptoms of low sodium include nausea and vomiting, muscle cramps and weakness, headache, and confusion. More serious symptoms include seizures, loss of consciousness, and coma.
We often cut down our salt intake to manage medical conditions like high blood pressure and maintain a healthy lifestyle in general. However, a less-than-normal level of sodium in our blood can also be harmful. We need the right amount of sodium —neither too much nor too little—in order for our body to function properly.
Hyponatremia is defined as having less than normal sodium in your blood. This is below 135 milliequivalents/liter (mEq/L). A normal sodium level is between 135 and 145 milliequivalents per liter (mEq/L).
Sodium is an electrolyte that helps to manage the amount of water in and around your cells. It plays an important role in regulating blood pressure and ensuring that your muscles and nerves work properly.
When there is too little sodium, water levels in your tissues can increase rapidly, causing them to swell. This can be especially harmful to your brain.
The elderly are at higher risk of developing hyponatremia due to medications or underlying health issues that cause sodium levels to drop. Medications that can increase the risk of low sodium include diuretics (water pills), antidepressants, and some pain relievers. Chronic health conditions affecting the heart, kidneys, and liver can also cause low sodium levels.
In the elderly, sodium levels in the blood can drop for several reasons. Certain medications, chronic health conditions, and age-related changes all play a role. In most cases of hyponatremia, a combination of factors is responsible rather than a single one.
Certain medications can put you at higher risk of developing hyponatremia. These include:
Diuretics: Also known as water pills, diuretics work by increasing urination, which expels excess water and sodium from the body. They are often prescribed to treat high blood pressure, heart failure, and kidney and liver diseases. A high dose of diuretics may cause sodium levels to drop below normal.
Antidepressants: Some antidepressants, like selective serotonin reuptake inhibitors (SSRIs), can cause your kidneys to retain water. Increased water retention can dilute sodium levels in the blood. Antidepressants are generally used to treat depression, but they may also be prescribed to help with anxiety or fibromyalgia.
Pain relievers: Over-the-counter non-steroidal pain relievers (NSAIDs), such as aspirin and ibuprofen, can affect sodium levels in the body by causing the kidneys to retain fluid.
Antiepileptics: Medications used to treat seizures have been linked to low sodium levels in the body. This is due to their impact on hormones and kidney function.
Chronic health conditions that can impact sodium levels in the body include:
Kidney disease: People suffering from kidney disease may have trouble eliminating excess water from the body, leading to fluid retention. This can impact the balance between sodium and water levels, which can lead to low sodium.
Liver disease: Liver diseases, such as liver cirrhosis, can cause water retention, which can lead to electrolyte imbalance.
Heart disease: Heart disease, especially congestive heart failure, can cause low sodium levels. When the heart isn’t pumping efficiently, the body can misinterpret this as dehydration or low blood pressure. This causes hormones to be secreted that increase water retention.
Underactive thyroid or adrenal glands: Both underactive thyroid gland disorder (hypothyroidism) and underactive adrenal glands (Addison’s disease) can cause fluid retention. In Addison’s disease, low levels of aldosterone and cortisol hormones cause the kidneys to lose sodium and retain more water.
Diabetes: When blood sugar is high, the body draws extra water from the cells into the bloodstream. This can dilute the concentration of sodium in the blood. Additionally, increased urination due to kidney function or certain diabetes medications may also contribute to hyponatremia.
Syndrome of inappropriate anti-diuretic hormone (SIADH): SIADH occurs when your body produces too much antidiuretic hormone. This leads to water retention. SIADH may occur as a result of another medical condition, like cancer or lung disease, intake of certain medicines, or even brain surgery.
Several age-related changes can also impact sodium levels. These include:
Reduction in thirst: As we age, our thirst sensation can reduce. If you’re not drinking enough, this can lead to dehydration, which can impact sodium levels in the body.
Decreased kidney function: Kidney function also naturally reduces with age. This can impact the body’s ability to balance water and sodium levels.
Changes in hormones: The body’s ability to regulate salt and water balance through hormones may be compromised with age. This can change the way your body stores sodium.
How low sodium impacts you depends on the severity and the rate of drop in sodium levels. In this section, we’ll compare the different causes of low sodium.
Low sodium can be chronic, meaning there’s a gradual decline in sodium levels accompanied by milder symptoms. It can also be acute, where there’s a sudden drop in sodium levels, requiring immediate medical attention.
Dilutional hyponatremia, also called euvolemic hyponatremia, occurs when there is too much water in the body, which dilutes the concentration of sodium. It can stem from medical issues, such as hypothyroidism or Addison’s disease, or the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Certain antidepressant, pain-relieving, or diuretic medications may also exacerbate dilutional hyponatremia.
Depletional hyponatremia, or hypovolemic hypnatremia, occurs when the body loses too much sodium. This can happen through the kidneys, but it can also result from severe gastrointestinal (GI) problems, like vomiting and diarrhea.
Mild: 130-134 mEq/L
Moderate: 125-129 mEq/L
Severe: Below 125 mEq/L
Common signs and symptoms of low sodium include:
Nausea and/or vomiting
Muscle cramps and weakness
Headache
Extreme fatigue or lethargy
Confusion
Restlessness and irritability
Feeling off balance or falling
Seizures
Nausea and vomiting are typical early symptoms of low sodium. You might also experience headaches, muscle weakness, or cramps. Because low sodium levels impact the brain, changes in mood or behavior, like irritability, confusion, or difficulty making decisions may also appear.
Low sodium levels may also cause you to feel off balance, raising the risk of falls. Severe hyponatremia may result in seizures or coma.
Seizures, coma, confusion, and loss of consciousness are all emergency symptoms that require urgent medical care. If you have mild or moderate symptoms that only seem to get worse, seek immediate medical care.
Knowing the risk factors for low sodium can improve awareness, leading to early detection, diagnosis, and treatment. This is especially important for the elderly as their symptoms can worsen rapidly due to a combination of factors.
If you’re taking a diuretic, antidepressant, or pain killer, it’s a good idea to discuss your risk for developing low blood sodium with your doctor.
Having a heart, kidney, or liver condition can also put you at higher risk. People in health care settings face greater risks. For instance, 18% of those aged 60 and above in nursing homes had low blood sodium. In contrast, only 7.7% of the general population aged 55 and above experienced this issue.
If you do take a medication that puts you at higher risk for low blood sodium, your doctor will likely monitor how your body is responding to the medication.
This will help ensure that you are on the right dose. As taking multiple medications can further increase your risk, your doctor must be aware of all medications that you are taking, both prescription and non-prescription.
If you have low blood sodium, then your doctor might recommend that you change the amount of salt you consume or the amount of water you drink.
However, it’s important to do this under medical supervision to ensure that your sodium levels remain at the right level. Eating healthy, well-balanced meals is also important for your overall health, including your sodium levels.
If you drink alcohol, your doctor might recommend you to limit the intake or stop drinking altogether, as alcohol can impact your hydration levels. Starting or maintaining an exercise routine is also recommended, as this helps your body balance sodium and water levels. If you don’t already have an exercise regimen, check with your doctor before getting started to ensure it’s a good fit for you.
Because low sodium levels can be a medical emergency, it’s important to know when to seek medical care.
Severe symptoms of low sodium are those that progress rapidly. Severe symptoms may affect the brain and cause confusion, disorientation, irritation, and changes in consciousness.
If you or someone you know has seizures, confusion, or loses consciousness, seek medical help right away.
If you take medication or have a health issue that increases your risk of low sodium, your doctor may suggest regular sodium level tests.
Letting your doctor know about any changes in how you feel can help them to better monitor your condition. It’s also important to work with your doctor to manage any medical conditions, as treating these medical conditions can help lower your risk of hyponatremia.
In the elderly, low blood sodium, or hyponatremia, is typically the result of a medication and/or medical condition. Medications like diuretics, antidepressants, and antiseizure medications can raise your risk. Having a heart, kidney, or liver condition or hormonal imbalance can also increase your risk.
If you or a loved one has multiple risk factors for low sodium, it’s important to be aware of the symptoms to ensure they receive timely medical attention. Working with your doctor can help prevent low blood sodium and manage it if it does occur.
Disclaimer: If you have concerns or questions about your health, it’s important to consult a healthcare professional.
Diuretics (water pills) and some types of antidepressants are commonly linked to low sodium levels. Some antiseizure drugs and common painkillers can also increase your risk of low sodium.
Sodium levels can drop quickly, in under 48 hours. This is called acute hyponatremia. In chronic hyponatremia, symptoms develop more slowly, over a few days or weeks.
Drinking too much water can cause low sodium levels in the elderly. However, this isn’t common, as seniors tend to experience lower levels of thirst.
Nausea and vomiting, headaches, muscle cramps and weakness, and confusion are among the first signs of low sodium in older adults.
The treatment for low sodium in elderly patients depends on the cause and the severity. Your doctor might change your medication or restrict your fluid intake. In more severe cases, intravenous (IV) fluids or medications may be required.
Cleveland Clinic. (2022). Hyponatremia. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/17762-hyponatremia
Damanti, S., Pasina, L., Consonni, D., Azzolino, D., & Cesari, M. (2019). Drug-induced hyponatremia: NSAIDS, a neglected cause that should be considered. The Journal of Frailty & Aging, 8(4), 222-223. https://doi.org/10.14283/jfa.2019.18
Durán Rebolledo, C. E., Sandoval-Calle, L. M., Holguín Jaramillo, J. F., Moncayo Libreros, P. A., & Useche-Henao, E. M. (2024). Tea and Toast Syndrome: A Case Report. Gerontology and Geriatric Medicine, 10. https://doi.org/10.1177/23337214241283647
Filippatos, T. D., Makri, A., Elisaf, M. S., & Liamis, G. (2017). Hyponatremia in the elderly: Challenges and Solutions. Clinical Interventions in Aging, 12(12), 1957–1965. https://doi.org/10.2147/CIA.S138535
Hamrahian, S. (2019). Hyponatremia: Practice essentials, pathophysiology, epidemiology. EMedicine. https://emedicine.medscape.com/article/242166-overview
Kugler, J. P., & Hustead, T. (2000). Hyponatremia and Hypernatremia in the Elderly. American Family Physician, 61(12), 3623–3630. https://www.aafp.org/pubs/afp/issues/2000/0615/p3623.html
Liamis, G., Milionis, H., & Elisaf, M. (2008). A Review of Drug-Induced Hyponatremia. American Journal of Kidney Diseases, 52(1), 144–153. https://doi.org/10.1053/j.ajkd.2008.03.004
Mayo Clinic. (2017). Low blood sodium in older adults: A concern? Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/hyponatremia/expert-answers/low-blood-sodium/faq-20058465
MedlinePlus. (2016). Low blood sodium: MedlinePlus Medical Encyclopedia. Medlineplus.gov. https://medlineplus.gov/ency/article/000394.htm
MedlinePlus. (2016). Syndrome of inappropriate antidiuretic hormone secretion: MedlinePlus Medical Encyclopedia. Medlineplus.gov. https://medlineplus.gov/ency/article/000314.htm
Merck Manuals Professional Edition. Hyponatremia - Endocrine and Metabolic Disorders. (n.d.). https://www.merckmanuals.com/en-ca/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hyponatremia
National Kidney Foundation. (2023, November 1). Hyponatremia (low sodium level in the blood). National Kidney Foundation. https://www.kidney.org/kidney-topics/hyponatremia-low-sodium-level-blood
Nelson, J. M., & Robinson, M. V. (2012). Hyponatremia in older adults presenting to the emergency department. International Emergency Nursing, 20(4), 251–254. https://doi.org/10.1016/j.ienj.2012.02.002
Rondon, H., & Badireddy, M. (2023, June 14). Hyponatremia. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK470386/
