The labeling for Byetta, a drug used to treat type 2 diabetes, has been revised to include new safety information about possible kidney function problems, including kidney failure.
Byetta was approved by the Food & Drug Administration (FDA) in 2005 to help type 2 diabetics better control blood sugar when other drugs were not adequate. The twice-daily injection is a synthetic form of a lizard hormone that boosts the production of insulin. Insulin is vital to controlling blood sugar levels.
According to a notice posted on the FDA Web site, from April 2005 through October 2008, the agency received 78 cases of altered kidney function (62 cases of acute renal failure and 16 cases of renal insufficiency), in patients using Byetta. Cases of acute renal failure or insufficiency occurred as soon as 3 days and up to 2 years after initiation of Byetta. The patient ages ranged from 23 to 83 years, with an average age of 60 years.
Some cases occurred in patients with pre-existing kidney disease or in patients with one or more risk factors for developing kidney problems, the FDA said. The agency also noted that the most common Byetta side effects include nausea, vomiting, and diarrhea. These side effects may have contributed to the development of altered kidney function. Kidney malfunction can result in a build-up of waste products in the blood, leading to serious illness or life-threatening conditions.
According to the FDA, hospitalization was required in 71 of 78 (91%) patients and there were 4 deaths reported in the cases reviewed. Eighteen patients required dialysis and two patients required kidney transplantation after initiation of Byetta.
Byetta was discontinued in 63 of 78 (80%) patients, with 39 (50%) patients reporting improved signs and symptoms after discontinuation of the drug. One patient experienced recurrent altered kidney function after re-initiation of Byetta.
Due to the serious potential consequences of altered kidney function, the FDA has approved the following revisions to the drug label for Byetta to describe this risk:
- Information regarding post-market reports of acute renal failure and insufficiency, highlighting that Byetta should not be used in patients with severe renal impairment (creatinine clearance <30 ml/min) or end-stage renal disease.
- Recommendations to healthcare professionals that caution should be applied when initiating or increasing doses of Byetta from 5 mcg to 10 mcg in patients with moderate renal impairment (creatinine clearance 30 to 50 ml/min).
- Recommendations that healthcare professionals monitor patients carefully for the development of kidney dysfunction, and evaluate the continued need for Byetta if kidney dysfunction is suspected while using the product.
- Information about kidney dysfunction in the patient Medication Guide to help patients understand the benefits and potential risks associated with Byetta.
Patients taking Byetta should be aware that problems with kidney function could lead to changes in urine color, frequency of urination or the amount of urine, unexplained swelling of the hands or feet, fatigue, changes in appetite or digestion, or dull ache in mid to lower back, the FDA said. Byetta patients who experience any of these symptoms should immediately discuss them with their health care professional.