Which drug is known to cause renal impairment as a side effect?

Lithium is known for its potential to cause renal impairment, particularly in long-term treatment scenarios. The kidneys play a crucial role in excreting lithium, and with prolonged use, there can be an accumulation leading to toxicity and various renal issues. This includes nephrogenic diabetes insipidus, which affects the kidneys' ability to concentrate urine, resulting in increased urine output and potential dehydration. Monitoring renal function is vital for patients on lithium, reflecting its specific nephrotoxic potential.

Other medications listed, such as valproic acid, lamotrigine, and carbamazepine, have their own side effects but are not primarily associated with renal impairment in the same way lithium is. Valproic acid can cause hepatotoxicity and may affect platelets, lamotrigine is more commonly related to skin reactions and CNS effects, and carbamazepine can influence bone marrow but does not have a prominent renal impairment profile.