What is the relationship between NSAIDs and Lithium levels?

The relationship between NSAIDs (non-steroidal anti-inflammatory drugs) and lithium levels is important to understand due to the potential effects of NSAIDs on lithium excretion. Specifically, NSAIDs can increase lithium levels in the body. This occurs because NSAIDs can inhibit renal prostaglandin synthesis, which in turn can lead to reduced renal clearance of lithium. As a result, patients who are taking both NSAIDs and lithium may experience elevated levels of lithium, raising the risk of lithium toxicity.

Since lithium has a narrow therapeutic window, careful monitoring of lithium levels is essential when patients are concurrently using NSAIDs to prevent adverse effects. It's important for clinicians to be aware of this interaction and to manage the dosage and frequency of lithium monitoring accordingly.

In contrast, the other options do not accurately describe the interaction. NSAIDs do not lower lithium levels, nor do they have no effect on lithium levels—these options ignore the established evidence of increased lithium levels resulting from NSAID use. Additionally, while NSAIDs are not outright contraindicated with lithium, caution should be exercised because of the potential increase in lithium levels and associated risks.