Overview
Acute kidney injury (AKI) is largely diagnosed in hospital settings. AKI occurring in the community is much less common and may escape diagnosis, partly because it can be asymptomatic or involve mild episodes that go unrecognised. In Australia, the diagnosed cases are predominantly hospital-based, and admission is common for monitoring and management.

Population at risk
AKI in Australia shows strong associations with age; the elderly constitute a major risk group. The indigenous population is another high-risk group, likely due to higher baseline rates of chronic kidney disease (CKD), diabetes, and vascular disease. Multiple underlying conditions are common among those diagnosed with AKI, with a notable proportion presenting with injury and poisoning as a primary diagnosis (i.e., an exposure or toxin causing kidney injury). However, most AKI cases are linked to general medical conditions, with circulatory system disease being the most common.

Major drug culprits: the triple whammy
The most important group of drugs to be aware of is the so-called triple whammy, consisting of diuretics, angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs), and nonsteroidal anti-inflammatory drugs (NSAIDs), including COX-2 inhibitors. These three drug classes are implicated in about $50\%$ of drug-induced kidney injury in Australia. Although the full combination (all three classes together) is relatively uncommon, it accounts for around $20\%$ of reported AKI cases. The three drug groups are present whether or not AKI has been diagnosed, and the risk rises with the number of these drugs a patient is taking.

Case illustration: a classic triple whammy scenario
A typical illustrative case involves a patient with diabetes, gout, heart failure, and a urinary tract infection who becomes dehydrated from poor intake. She is on a diuretic, an ACE inhibitor, and an NSAID, plus a diabetes drug cleared by the kidneys. On presentation, her creatinine is already elevated and rises further despite treatment, peaking at about $10\times$ the average creatinine level and about $5\times$ the patient’s baseline. The creatinine then trends back toward normal, though not always returning completely to pre-event levels, suggesting possible lasting damage. This scenario exemplifies how the interaction of the triple whammy can drive AKI.

Quantitative contributions of drug groups
Overall, the three drug groups (diuretics, ACE inhibitors/ARBs, and NSAIDs) account for around $50\%$ of drug-induced kidney injury in Australia. The triple combination (taking all three classes) is linked with about $20\%$ of reported AKI cases. In addition to these, other drugs contribute smaller portions: radiocontrast media account for roughly $10\%$, cyclosporine (used in renal transplant recipients) around $10\%$, and aminoglycoside antibiotics also about $10\%$. The remainder comprises a wide array of less common causes.

Clinical and epidemiological implications
There is a strong correlation between creatinine elevation and the number of offending drugs present; in practice, when patients are exposed to all three components of the triple whammy, AKI is more likely and may be more severe. Importantly, these three drug classes are active contributors to kidney injury even if the AKI diagnosis has not yet been made, underscoring the need for careful medication review and renal function monitoring in at-risk patients.

Global context: toxic AKI in developing countries
Australia reports relatively low rates of toxic AKI. In contrast, developing countries experience higher rates of AKI due to toxins, including plant or animal toxins, bacterial toxins, snake bites, and wasp stings. Environmental contamination and poorer regulation lead to exposure to heavy metals such as arsenic and lead, as well as pesticides. Dehydration and heat stroke further compound risk in these settings, contributing to a more complex pattern of AKI in developing regions.

Takeaways
The key messages are: AKI is most often diagnosed in hospital; elderly and Indigenous Australians are higher-risk groups; the triple whammy (diuretics + ACE inhibitors/ARBs + NSAIDs) is a major, tractable driver of drug-induced AKI, accounting for about half of cases, with the triple combination responsible for around one-fifth of reported AKI; radiocontrast media, cyclosporine, and aminoglycosides each contribute about one-tenth of cases; and toxin-related AKI is comparatively more common in developing countries due to environmental and exposure factors. In all settings, awareness of these drugs and risk factors is essential for prevention and early detection of AKI.