Severe Acute Exacerbation of Hepatitis B after Discontinuation of Treatment: Discontinuation of anti-hepatitis B therapy, including Tenofovir alafenamide may result in severe acute exacerbations of hepatitis B. Patients who discontinue Tenofovir alafenamide should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment. If appropriate resumption of antihepatitis B therapy may be warranted.Risk of Development of HIV-1 Resistance in Patients Coinfected with HBV and HIV-1: Due to the risk of development of HIV-1 resistance Tenofovir alafenamide alone is not recommended for the treatment of HIV-1 infection. The safety and efficacy of Tenofovir alafenamide have not been established in patients coinfected with HBV and HIV-1. HIV antibody testing should be offered to all HBV-infected patients before initiating therapy with Tenofovir alafenamide and if positive, an appropriate antiretroviral combination regimen that is recommended for patients coinfected with HIV-1 should be used.New Onset or Worsening Renal Impairment: Postmarketing cases of renal impairment, including acute renal failure, proximal renal tubulopathy (PRT) and Fanconi syndrome have been reported with TAF-containing products; while most of these cases were characterized by potential confounders that may have contributed to the reported renal events, it is also possible these factors may have predisposed patients to tenofovir- related adverse events. Patients taking tenofovir prodrugs who have impaired renal function and those taking nephrotoxic agents, including non-steroidal anti-inflammatory drugs, are at increased risk of developing renal-related adverse reactions. Prior to or when initiating Tenofovir alafenamide and during treatment with Tenofovir alafenamide on a clinically appropriate schedule, assess serum creatinine, estimated creatinine clearance, urine glucose and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue Tenofovir alafenamide in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome.Lactic Acidosis/Severe Hepatomegaly with Steatosis: Lactic acidosis and severe hepatomegaly with steatosis including fatal cases have been reported with the use of nucleoside analogs including tenofovir disoproxil fumarate (TDF) another prodrug of tenofovir alone or in combination with other antiretrovirals. Treatment with Tenofovir alafenamide should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity (which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations).
