Clinical Case 83: Answer and Summary

Which one of these drugs is the most common culprit in acute allergic interstitial nephritis now?

Amoxicillin 13%
Omeprazole 37%
Ciprofloxacin 24%
Ibuprofen 24%

Classically, drug induced AIN has been most commonly linked with antibiotics and NSAIDS. Recently, PPIs have emerged as a more common cause of AIN than the other drugs. This might be due to the massive use of these agents for almost all patients that are admitted to the hospital for ulcer ppx.  A recent study from Mayo Clinic looked at biopsy proven AIN in a single center retrospectively and identified the culprits. Drugs were 70% of the causes followed by autoimmune diseases. The most common class of drugs were antibiotics followed by PPI and then antibiotics. But overall, the top 3 causes were omeprazole, amoxicillin and then ciprofloxacin.  Patients with PPI induced AIN were older, not as symptomatic and had longer duration of drug exposure till getting kidney biopsy.