The Food and Drug Administration has granted accelerated approval to budesonide (Tarpeyo) to reduce proteinuria in adults with primary immunoglobulin A (IgA) nephropathy, also known as Berger's disease. In IgA nephropathy, IgA (a type of antibody) builds up in the glomeruli of the kidney, causing inflammation (glomerulonephritis) and a gradual decrease in the kidney's ability to filter the blood. The inflammation and decrease in filtering lead to tissue damage in the kidneys, causing them to leak blood and protein into the urine. Complications of IgA nephropathy include hypertension, elevated cholesterol levels, acute or chronic kidney disease, kidney failure, and nephrotic syndrome.

Budesonide is a corticosteroid with potent glucocorticoid activity and weak mineralocorticoid activity that undergoes substantial first pass metabolism. Mucosal B cells in the ileum produce IgA1 antibodies, which cause IgA nephropathy. Budesonide has antiinflammatory and immunosuppressant effects and can modulate the numbers of B cells and their activity. As a corticosteroid, budesonide can cause adverse effects similar to those caused by other corticosteroids. It can suppress endogenous cortisol concentrations and impair hypothalamus-pituitary-adrenal axis function. The most common adverse effects of budesonide are hypertension; peripheral edema; muscle spasms; acne; dermatitis; weight gain; dyspnea; facial edema; dyspepsia; fatigue; and excess hair, often around the nose and mouth.

The effectiveness of budesonide on proteinuria was assessed in a randomized, double-blind, placebo-controlled, multicenter study of 199 participants with IgA nephropathy, reduced kidney function, and proteinuria who were taking a maximally tolerated renin-angiotensin inhibitor. The primary end point was the percent reduction in the urine protein-to-creatinine ratio at nine months compared with the beginning of the study. Those receiving budesonide had a significant reduction in the urine protein-to-creatinine ratio compared with those receiving placebo (34% versus 5%). It has not yet been established if budesonide slows the decline of kidney function in people with IgA nephropathy.

Nurses should assess if any coadministered drugs are potent cytochrome P-450 (CYP) 3A4 inhibitors (for example, ketoconazole or grapefruit juice) because these can increase circulating levels of budesonide, which is metabolized by CYP3A4; concurrent use should be avoided. Patients should be advised to not drink grapefruit juice while taking budesonide. Because budesonide causes immunosuppression, nurses should advise patients to avoid exposure to people with illnesses and infections such as chicken pox, measles, or tuberculosis, or to other fungal, bacterial, viral, or parasitic infections.

For complete prescribing information for budesonide, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2021/215935s000lbl.pdf.