Collectively, these newly identified effects of Invokana on heart and kidney disease show significantly enhanced benefits of this medicine. Safety information from recent clinical trials also suggests that the risk of amputation, while still increased with canagliflozin, is lower than previously described, particularly when appropriately monitored. Based on these considerations, we have concluded that the Boxed Warning should be removed.
The FDA has now released a new warning against biotin interference with troponin, an essential heart blood test. Biotin or vitamin B7 is a water-soluble molecule found in many over-the-counter supplements such as multivitamins, prenatal, and in those that are meant to improve or protect the health of hair, skin, and nail.
Vitamin B7 is a central catalyst in many laboratory tests, especially those measuring troponin and thyroid hormone levels. When patients take high doses of biotin, especially >30 micrograms daily, it has the potential to underestimate the blood troponin concentration. Troponin measurements are critical in identifying adults with heart disease and particularly those having an acute event such as heart attack or myocardial infarction.
High doses of biotin intake, up to 300 mg daily, have been documented in patients with multiple sclerosis. These extraordinary doses may translate up to 1,200 ng/mL blood concentrations. Biotin has a short half-life of about two hours. It may be reasonable to suspend vitamin B7 intake for two to three days before undergoing any laboratory testing that incorporates biotin-analyte technology.
Patients, physicians, and laboratory personnel should be aware of possible interference of oral biotin with blood troponin and thyroid hormone testing, particularly in decisive clinical circumstances. A grave example would be a biotin user who presents clinically with a heart attack, and yet troponin measurements appear to be normal. Non-elevated troponin can lead to missed diagnosis and life-saving intervention.