Neurologist reveals shocking truth about 3 medicines that cause life-threatening low blood sodium levels in the body |
Low blood sodium, medically known as hyponatremia, is a condition in which the concentration of sodium in the blood falls below normal levels, leading to fluid imbalance in and around cells. Although it may begin with subtle symptoms such as fatigue or confusion, untreated hyponatremia can progress to serious complications, including seizures or coma. Dr Sudhir Kumar, senior neurologist at Apollo Hospitals, Hyderabad, has drawn attention to the risk posed by three commonly prescribed categories of medicines in triggering dangerously low sodium levels in his post on X. With many patients on long-term medication regimes, especially older adults, the risk of hyponatremia may be under-recognised.
What is hyponatremia (low blood sodium) and why does it matter
Sodium is a key electrolyte responsible for regulating water distribution in the body’s cells and maintaining various bodily functions. When blood sodium levels drop too low, water moves into cells, causing them to swell. In mild cases, this may result in nausea, headache, or dizziness; in more severe cases, the swelling can affect brain cells and lead to seizures or loss of consciousness. Medical literature recognises hyponatremia as potentially life-threatening if not detected and addressed promptly.
Medicines that can trigger low blood sodium levels in body (Hyponatremia)
In his post shared on X, Dr Kumar identifies three classes of medication that are frequently prescribed yet can contribute to low blood sodium levels, especially in older patients or those with other risk factors.
1. Thiazide Diuretics
These include medications such as hydrochlorothiazide and indapamide, commonly used to manage high blood pressure. They work by increasing the body’s excretion of sodium and water through urine. In some cases, the loss of sodium may outpace the body’s ability to maintain normal levels, leading to hyponatremia. Elderly patients or those who are dehydrated may be particularly vulnerable.
2. Selective Serotonin Reuptake Inhibitors (SSRIs)
SSRIs, such as sertraline or escitalopram, are used to treat depression and anxiety. They can influence the secretion of antidiuretic hormone (ADH), which governs water retention in the body. Higher levels of ADH may cause excess water retention, diluting sodium concentrations. Patients who also use diuretics or have other illnesses are at higher risk.
3. Carbamazepine and Oxcarbazepine
These medications are used for seizure control or as mood stabilisers. They are known to sometimes trigger a condition called Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH), which causes excessive ADH release and a corresponding drop in sodium levels. The risk is higher in patients with other comorbidities or taking multiple medications.
Who is at risk of low blood sodium and what increases the danger
While these medications are widely used, certain factors raise the risk of developing hyponatremia:
- Older age, as sodium regulation and kidney function decline with age.
- Concurrent use of multiple medications that affect sodium or water balance (for instance, a diuretic and an SSRI).
- Dehydration due to illness, vomiting, or diarrhoea.
- Underlying conditions like heart failure, liver disease, or kidney disorders.
- Drinking excessive amounts of fluid (in some cases) can dilute sodium further.
When several risk factors overlap, the danger increases significantly.
Low blood sodium levels in body: Signs and symptoms to watch for
Early detection of low sodium is key. Patients and caregivers should be alert to symptoms, including:
- Unusual fatigue or lethargy.
- Confusion, difficulty concentrating, or disorientation.
- Dizziness or light-headedness, particularly when standing up.
- Muscle weakness, cramps or spasms.
- Headache or nausea, and vomiting.
- In more severe cases: seizures, loss of consciousness or coma.
Anyone on high-risk medication who develops these symptoms should seek medical attention immediately.
How hyponatremia is diagnosed and managed
Diagnosis typically involves a blood test measuring serum sodium concentration. If sodium is low, further tests may assess water balance, kidney and liver function, hormone levels (including ADH), and possible medication causes. Management may include:
- Adjusting or stopping the offending medication under a doctor’s guidance.
- Restricting fluid intake in some cases to avoid further dilution of sodium.
- Administering intravenous sodium solutions in more severe cases.
- Monitoring sodium levels regularly, particularly when starting high-risk medicine or in patients with multiple risk factors.
Dr Kumar emphasises that anyone on these therapies who begins experiencing relevant symptoms should get their sodium checked.
Implications for patients and practitioners
For prescribing doctors, awareness of the sodium-lowering potential of certain medications is important. It may warrant caution, especially when prescribing to older adults or patients with multiple comorbidities. Monitoring strategies may need to be built into care plans. For patients, the message is one of vigilance: understanding potential side-effects, recognising early symptoms, and maintaining regular check-ups. Hyponatremia may be preventable or treatable with timely action.Profoundly low sodium levels can lead to severe health outcomes, ranging from seizures to coma. Three widely-used categories of medicine: thiazide diuretics, SSRIs, and the anti-seizure drugs carbamazepine/oxcarbazepine have been linked by medical experts to an increased risk of hyponatremia. While they perform important roles in the treatment of high blood pressure, depression, anxiety and seizures, careful monitoring, patient education, and prompt intervention can mitigate the risk.
Disclaimer: This article provides general information for educational purposes and should not be considered medical advice. Please consult a qualified healthcare professional for personalised guidance.
