From the Research
Losartan is not absolutely contraindicated in patients with hyponatremia, but caution is warranted due to the potential risk of worsening sodium levels, as reported in a case study from 2015 1. Patients with hyponatremia should be monitored closely when taking losartan, as this medication can potentially worsen sodium levels in certain situations. Losartan, an angiotensin II receptor blocker (ARB), works by blocking the renin-angiotensin-aldosterone system, which can affect sodium and water balance in the body. The concern arises because ARBs like losartan can reduce aldosterone levels, which normally promotes sodium retention. In patients with conditions that predispose to hyponatremia (such as heart failure, cirrhosis, or those on diuretics), losartan may exacerbate sodium imbalance. Some studies suggest that low-dose losartan may have beneficial effects on sodium homeostasis in certain patient populations, such as those with preascitic cirrhosis 2. However, other studies have reported cases of losartan-induced hyponatremia, highlighting the need for caution and close monitoring 1, 3. Regular monitoring of serum electrolytes, particularly sodium levels, is essential when initiating losartan in patients with pre-existing hyponatremia. The standard starting dose of losartan is 50 mg once daily, but a lower starting dose of 25 mg may be considered in patients with hyponatremia. If hyponatremia worsens during treatment, dose adjustment or discontinuation may be necessary. The underlying cause of hyponatremia should also be addressed concurrently with any ARB therapy. Key considerations for managing patients with hyponatremia on losartan include:
- Close monitoring of serum sodium levels
- Regular assessment of renal function and volume status
- Adjustment of losartan dose or discontinuation if hyponatremia worsens
- Addressing the underlying cause of hyponatremia
- Considering alternative antihypertensive therapies if necessary.