From the Guidelines
Losartan can interact with lithium, potentially leading to increased lithium levels and toxicity. When considering the management of patients on both losartan and lithium, it's crucial to understand the potential for this interaction, which can be serious. The mechanism behind this interaction involves the effect of losartan, an angiotensin-receptor blocker (ARB), on renal function and lithium clearance. Although the provided study 1 does not directly address the interaction between losartan and lithium, it discusses the importance of monitoring renal function and electrolytes in patients on lithium, highlighting the potential for renal tubular dysfunction with lithium use. Given the potential for losartan to affect kidney function and thereby lithium clearance, patients on both medications should be closely monitored. Key points to consider include:
- Monitoring lithium levels more frequently, especially when starting, stopping, or changing the dose of losartan.
- Potential need to adjust lithium doses to prevent toxicity.
- Importance of reporting any unusual symptoms promptly to the healthcare provider. It's also worth noting that while the study 1 from 2014 provides valuable insights into the management of patients with chronic kidney disease and the use of lithium, the most recent and highest quality evidence should always be consulted for the latest recommendations on managing potential drug interactions. However, based on the principles of pharmacology and the known effects of ARBs on renal function, it is clear that careful monitoring and potentially dose adjustments are necessary when losartan and lithium are used concomitantly.
From the FDA Drug Label
Losartan Potassium Tablets and certain other medicines may interact with each other Especially tell your doctor if you are taking: • lithium (a medicine used to treat a certain kind of depression)
Losartan can interact with lithium. It is recommended to inform your doctor if you are taking lithium, as it may interact with losartan. 2
From the Research
Interaction between Losartan and Lithium
- There is no direct evidence in the provided studies that specifically addresses the interaction between losartan and lithium.
- However, the studies suggest that lithium can have adverse effects on the kidneys, and drugs that affect renal blood flow and function can potentially interact with lithium 3, 4.
- Losartan is an angiotensin II receptor antagonist (AT1 antagonist) that can affect renal blood flow and function.
- A study found that AT1 antagonists, such as losartan, can potentially interact with lithium and increase lithium serum levels 4.
- Therefore, it is possible that losartan may interact with lithium, although the exact nature and extent of this interaction are not clear from the provided studies 4.
Mechanism of Interaction
- The interaction between losartan and lithium may be related to the effect of losartan on renal blood flow and function, which can affect lithium excretion and increase lithium serum levels 4.
- The study found that the number of potentially interacting drugs, including AT1 antagonists like losartan, was significantly associated with increasing serum levels of lithium 4.