What is a classic drug known to cause Acute Interstitial Nephritis?

Acute Interstitial Nephritis (AIN) is a known adverse reaction associated with certain medications, particularly those that can induce an allergic reaction leading to inflammation of the renal interstitium. Among the options presented, penicillin is a classic drug associated with AIN due to its immunological reactions that can occur in some individuals.

Penicillin can elicit a hypersensitivity response in susceptible individuals, leading to the accumulation of inflammatory cells in the renal interstitium, which is characteristic of AIN. This condition can manifest with symptoms such as fever, rash, eosinophilia, and renal impairment shortly after the medication is administered.

While amoxicillin is also a type of penicillin and can potentially cause AIN, the question specifically highlights penicillin itself as a classic example, as it has been historically well-documented in the literature as a cause of this condition. Other antibiotics, such as vancomycin and ciprofloxacin, can have kidney-related side effects but are not classically recognized as common causative agents for AIN in the same way as penicillin.