TENOFOVIR DISOPROXIL FUMARATE Tablets
Brand names: TENOFOVIR DISOPROXIL FUMARATE
Boxed warning
WARNING: POSTTREATMENT ACUTE EXACERBATION OF HEPATITIS B Severe acute exacerbations of hepatitis B virus (HBV) have been reported in HBV-infected patients who have discontinued anti-hepatitis B therapy, including tenofovir disoproxil fumarate. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in HBV-infected patients who discontinue anti-hepatitis B therapy, including tenofovir disoproxil fumarate. If appropriate, resumption of anti-hepatitis B therapy may be warranted [see Warnings and Precautions ( 5.1 )] . WARNING: POSTTREATMENT ACUTE EXACERBATION OF HEPATITIS B S e e full prescribing information for complete boxed warning. Severe acute exacerbations of hepatitis B virus (HBV) have been reported in HBV-infected patients who have discontinued anti-hepatitis B therapy, including tenofovir disoproxil fumarate. Hepatic function should be monitored closely in HBV-infected patients who discontinue tenofovir disoproxil fumarate. If appropriate, resumption of anti-hepatitis B therapy may be warranted. ( 5.1 )
Warnings
5 WARNINGS AND PRECAUTIONS New onset or worsening renal impairment: Can include acute renal failure and Fanconi syndrome. Avoid administering tenofovir disoproxil fumarate with concurrent or recent use of nephrotoxic drugs. ( 5.2 ) HIV testing: HIV antibody testing should be offered to all HBV-infected patients before initiating therapy with tenofovir disoproxil fumarate. Tenofovir disoproxil fumarate should only be used as part of an appropriate antiretroviral combination regimen in HIV-infected patients with or without HBV coinfection. ( 5.3 ) Immune reconstitution syndrome: May necessitate further evaluation and treatment. ( 5.4 ) Decreases in bone mineral density (BMD): Consider assessment of BMD in patients with a history of pathologic fracture or other risk factors for osteoporosis or bone loss. ( 5.5 ) Lactic acidosis/severe hepatomegaly with steatosis: Discontinue treatment in patients who develop symptoms or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity. ( 5.6 ) 5.1 Severe Acute Exacerbation of Hepatitis B in Patients with HBV Infection All patients should be tested for the presence of chronic hepatitis B virus (HBV) before or when initiating tenofovir disoproxil fumarate [see Dosage and Administration ( 2.1 )] . Discontinuation of anti-HBV therapy, including tenofovir disoproxil fumarate, may be associated with severe acute exacerbations of hepatitis B. Patients infected with HBV who discontinue tenofovir disoproxil fumarate should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment. If appropriate, resumption of anti-hepatitis B therapy may be warranted, especially in patients with advanced liver disease or cirrhosis, since posttreatment exacerbation of hepatitis may lead to hepatic decompensation and liver failure. 5.2 New Onset or Worsening Renal Impairment Tenofovir is principally eliminated by the kidney. Renal impairment, including cases of acute renal failure and Fanconi syndrome (renal tubular injury with severe hypophosphatemia), has been reported with the use of tenofovir disoproxil fumarate [see Adverse Reactions ( 6.2 )] . Prior to initiation and during use of tenofovir disoproxil fumarate, 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. Dosing interval adjustment of tenofovir disoproxil fumarate tablets and close monitoring of renal function are recommended in all patients with creatinine clearance below 50 mL/min [see Dosage and Administration ( 2.4 )] . No safety or efficacy data are available in patients with renal impairment who received tenofovir disoproxil fumarate using these dosing guidelines, so the potential benefit of tenofovir disoproxil fumarate therapy should be assessed against the potential risk of renal toxicity. Tenofovir disoproxil fumarate tablets should be avoided with concurrent or recent use of a nephrotoxic agent (e.g., high-dose or multiple non-steroidal anti-inflammatory drugs [NSAIDs]) [see Drug Interactions ( 7.1 ) ] . Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in HIV-infected patients with risk factors for renal dysfunction who appeared stable on TDF. Some patients required hospitalization and renal replacement therapy. Alternatives to NSAIDs should be considered, if needed, in patients at risk for renal dysfunction. Persistent or worsening bone pain, pain in extremities, fractures and/or muscular pain or weakness may be manifestations of proximal renal tubulopathy and should prompt an evaluation of renal function in patients at risk of renal dysfunction. 5.3 Patients Coinfected with HIV-1 and HBV Due to the risk of development of HIV-1 resistance, tenofovir disoproxil fumarate should only be used in HIV-1 and HBV coinfected patients as part of an appropriate antiretroviral combination regimen. HIV-1 antibody testing should be offered to all HBV-infected patients before initiating therapy with tenofovir disoproxil fumarate. It is also recommended that all patients with HIV-1 be tested for the presence of chronic hepatitis B before initiating treatment with tenofovir disoproxil fumarate. 5.4 Immune Reconstitution Syndrome Immune reconstitution syndrome has been reported in HIV-1 infected patients treated with combination antiretroviral therapy, including tenofovir disoproxil fumarate. During the initial phase of combination antiretroviral treatment, HIV-1 infected patients whose immune system responds may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneu mocystis jirovecii pneumonia [PCP], or tuberculosis), which may necessitate further evaluation and treatment. Autoimmune disorders (such as Graves’ disease, polymyositis, and Guillain-Barré syndrome) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable, and can occur many months after initiation of treatment. 5.5 Bone Loss and Mineralization Defects Bone Mineral Density In clinical trials in HIV-1 infected adults, tenofovir disoproxil fumarate was associated with slightly greater decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism, suggesting increased bone turnover relative to comparators [see Adverse Reactions ( 6.1 )] . Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher in subjects receiving tenofovir disoproxil fumarate. Clinical trials evaluating tenofovir disoproxil fumarate in pediatric subjects were conducted. Under normal circumstances, BMD increases rapidly in pediatric patients. In HIV-1 infected subjects 2 years to less than 18 years of age, bone effects were similar to those observed in adult subjects and suggest increased bone turnover. Total body BMD gain was less in the tenofovir disoproxil fumarate-treated HIV-1 infected pediatric subjects as compared to the control groups. Similar trends were observed in chronic HBV-infected pediatric subjects 2 years to less than 18 years of age. In all pediatric trials, normal skeletal growth (height) was not affected for the duration of the clinical trials [see Adverse Reactions ( 6.1 )]. The effects of tenofovir disoproxil fumarate-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in adults and pediatric subjects 2 years and older are unknown. The long-term effect of lower spine and total body BMD on skeletal growth in pediatric patients, and in particular, the effects of long-duration exposure in younger children is unknown. Although the effect of supplementation with calcium and vitamin D was not studied, such supplementation may be beneficial. Assessment of BMD should be considered for adult and pediatric patients who have a history of pathologic bone fracture or other risk factors for osteoporosis or bone loss. If bone abnormalities are suspected, appropriate consultation should be obtained. Mineralization Defects Cases of osteomalacia associated with proximal renal tubulopathy, manifested as bone pain or pain in extremities and which may contribute to fractures, have been reported in association with tenofovir disoproxil fumarate use [see Adverse Reactions ( 6.2 )] . Arthralgia and muscle pain or weakness have also been reported in cases of proximal renal tubulopathy. Hypophosphatemia and osteomalacia secondary to proximal renal tubulopathy should be considered in patients at risk of renal dysfunction who present with persistent or worsening bone or muscle symptoms while receiving TDF-containing products [see Warnings and Precautions ( 5.2 )] . 5.6 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 TDF, alone or in combination with other antiretrovirals. Treatment with tenofovir disoproxil fumarate 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). 5.7 Risk of Adverse Reactions Due to Drug Interactions The concomitant use of tenofovir disoproxil fumarate and other drugs may result in known or potentially significant drug interactions, some of which may lead to possible clinically significant adverse reactions from greater exposures of concomitant drugs [see Drug Interactions ( 7.2 )] . See Table 12 for steps to prevent or manage these possible and known significant drug interactions, including dosing recommendations. Consider the potential for drug interactions prior to and during therapy with tenofovir disoproxil fumarate; review concomitant medications during therapy with tenofovir disoproxil fumarate; and monitor for adverse reactions associated with the concomitant drugs.
Contraindications
4 CONTRAINDICATIONS None. None. ( 4 )
Overdose
10 OVERDOSAGE If overdose occurs, the patient must be monitored for evidence of toxicity, and standard supportive treatment applied as necessary. Tenofovir is efficiently removed by hemodialysis with an extraction coefficient of approximately 54%. Following a single 300 mg dose of tenofovir disoproxil fumarate tablet, a four-hour hemodialysis session removed approximately 10% of the administered tenofovir dose.
Drug interactions
7 DRUG INTERACTIONS Tenofovir disoproxil fumarate increases didanosine concentrations. Dose reduction and close monitoring for didanosine toxicity are warranted. ( 7.2 ) Coadministration decreases atazanavir concentrations. When coadministered with tenofovir disoproxil fumarate, use atazanavir given with ritonavir. ( 7.2 ) Coadministration of tenofovir disoproxil fumarate with certain HIV-1 protease inhibitors or certain drugs to treat HCV increases tenofovir concentrations. Monitor for evidence of tenofovir toxicity. ( 7.2 ) Consult Full Prescribing Information prior to and during treatment for important drug interactions. ( 7.2 ) 7.1 Drugs Affecting Renal Function Tenofovir is primarily eliminated by the kidneys [see Clinical Pharmacology ( 12.3 ) ] . Coadministration of tenofovir disoproxil fumarate with drugs that are eliminated by active tubular secretion may increase concentrations of tenofovir and/or the coadministered drug. Some examples include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions ( 5.2 ) ]. Drugs that decrease renal function may increase concentrations of tenofovir. In the treatment of chronic hepatitis B, tenofovir disoproxil fumarate should not be administered in combination with HEPSERA (adefovir dipivoxil). 7.2 Established and Significant Interactions Table 12 provides a listing of established or clinically significant drug interactions. The drug interactions described are based on studies conducted with TDF [see Clinical Pharmacology ( 12.3 )]. T ab l e 12 Established and Significant a D rug Interactions: Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Trials Concomitant Drug Class: Drug Name Effect on Concentration b Clinical Comment NRTI: didanosine ↑ didanosine Patients receiving tenofovir disoproxil fumarate tablets and didanosine should be monitored closely for didanosine-associated adverse reactions. Discontinue didanosine in patients who develop didanosine-associated adverse reactions. Higher didanosine concentrations could potentiate didanosine-associated adverse reactions, including pancreatitis, and neuropathy. Suppression of CD4+ cell counts has been observed in patients receiving tenofovir disoproxil fumarate with didanosine 400 mg daily. In patients weighing greater than 60 kg, reduce the didanosine dose to 250 mg when it is coadministered with tenofovir disoproxil fumarate. In patients weighing less than 60 kg, reduce the didanosine dose to 200 mg when it is coadministered with tenofovir disoproxil fumarate. When coadministered, tenofovir disoproxil fumarate and Videx EC may be taken under fasted conditions or with a light meal (less than 400 kcal, 20% fat). HIV-1 Protease Inhibitors : atazanavir ↓ atazanavir When coadministered with tenofovir disoproxil fumarate tablets, atazanavir 300 mg should be given with ritonavir 100 mg. lopinavir/ritonavir atazanavir/ritonavir darunavir/ritonavir ↑ tenofovir Monitor patients receiving tenofovir disoproxil fumarate tablets concomitantly with lopinavir/ritonavir, ritonavir-boosted atazanavir, or ritonavir-boosted darunavir for TDF-associated adverse reactions. Discontinue tenofovir disoproxil fumarate tablets in patients who develop TDF-associated adverse reactions. Hepatitis C Antiviral Agents: sofosbuvir/velpatasvir sofosbuvir/velpatasvir/voxilaprevir ↑ tenofovir Monitor patients receiving tenofovir disoproxil fumarate tablets concomitantly with EPCLUSA ® (sofosbuvir/velpatasvir) for adverse reactions associated with TDF. ledipasvir/sofosbuvir Monitor patients receiving tenofovir disoproxil fumarate tablets concomitantly with HARVONI ® (ledipasvir/sofosbuvir) without an HIV-1 protease inhibitor/ritonavir or an HIV-1 protease inhibitor/cobicistat combination for adverse reactions associated with TDF. In patients receiving tenofovir disoproxil fumarate tablets concomitantly with HARVONI and an HIV-1 protease inhibitor/ritonavir or an HIV-1 protease inhibitor/cobicistat combination, consider an alternative HCV or antiretroviral therapy, as the safety of increased tenofovir concentrations in this setting has not been established. If coadministration is necessary, monitor for adverse reactions associated with TDF. a This table is not all inclusive b ↑=Increase, ↓=Decrease
Uses
1 INDICATIONS AND USAGE Tenofovir disoproxil fumarate tablets are a nucleotide analog HIV-1 reverse transcriptase inhibitor and an HBV reverse transcriptase inhibitor and is indicated: in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults and pediatric patients 2 years of age and older weighing at least 10 kg. ( 1.1 ) for the treatment of chronic hepatitis B in adults and pediatric patients 2 years and older weighing at least 10 kg. ( 1.2 ) 1.1 HIV-1 Infection Tenofovir disoproxil fumarate tablets are indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults and pediatric patients 2 years of age and older weighing at least 10 kg. 1.2 Chronic Hepatitis B Tenofovir disoproxil fumarate tablets are indicated for the treatment of chronic hepatitis B virus (HBV) in adults and pediatric patients 2 years of age and older weighing at least 10 kg.
Dosage forms & strengths
2 DOSAGE AND ADMINISTRATION Testing: Prior to or when initiating tenofovir disoproxil fumarate tablets test for hepatitis B virus infection and HIV-1 infection. Prior to initiation and during use of Tenofovir disoproxil fumarate tablets, 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 phosphorous. ( 2.1 ) Recommended tablet dosage in adults and pediatric patients weighing at least 35 kg: One tenofovir disoproxil fumarate 300 mg tablet once daily taken orally without regard to food. ( 2.2 ) Recommended dosage in pediatric patients at least 2 years of age and adults: Tablets: For patients weighing at least 17 kg who can swallow an intact tablet, one tenofovir disoproxil fumarate tablet (150 mg, 200 mg, 250 mg, or 300 mg based on body weight) once daily taken orally without regard to food. ( 2.2 ) Recommended dosage in renally impaired adult patients: Creatinine clearance (CrCL) 30 to 49 mL/min: 300 mg every 48 hours. ( 2.4 ) CrCL10 to 29 mL/min: 300 mg every 72 to 96 hours. ( 2.4 ) Hemodialysis: 300 mg every 7 days or after approximately 12 hours of dialysis. ( 2.4 ) 2.1 Testing Prior to Initiation of tenofovir disoproxil fumarate tablets for Treatment of HIV-1 Infection or Chronic Hepatitis B Prior to or when initiating tenofovir disoproxil fumarate tablets, test patients for HBV infection and HIV-1 infection. Tenofovir disoproxil fumarate tablets alone should not be used in patients with HIV-1 infection [see Warnings and Precautions ( 5.3 )]. Prior to initiation and during use of tenofovir disoproxil fumarate tablets, 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 [see Warnings and Precautions ( 5.2 )]. 2.2 Recommended Tablet Dosage in Adults and Pediatric Patients 2 Years and Older Weighing at Least 17 kg The recommended dosage of tenofovir disoproxil fumarate tablet in adults and pediatric patients weighing at least 35 kg is one 300 mg tablet taken orally once daily without regard to food. The dosage for tenofovir disoproxil fumarate tablets is the same for both HIV and HBV indications. The recommended dosage of tenofovir disoproxil fumarate tablets tablet in adults and pediatric patients 2 years and older weighing at least 17 kg is 8 mg of tenofovir disoproxil fumarate (TDF) per kg of body weight (up to a maximum of 300 mg) once daily. Dosage for pediatric patients 2 years and older weighing between 17 kg and 35 kg and able to swallow an intact tablet is provided in Table 1. Weight should be monitored periodically and the tenofovir disoproxil fumarate tablets dose adjusted accordingly. Table 1 Recommended Dosing for Patients 2 Years and Older and Weighing at Least 17 kg Using Tenofovir Disoproxil Fumarate Tablets Body Weight (kg) Dosing of Tenofovir Disoproxil Fumarate T ablets 17 to less than 22 one 150 mg tablet once daily 22 to less than 28 one 200 mg tablet once daily 28 to less than 35 one 250 mg tablet once daily at least 35 one 300 mg tablet once daily 2.4 Dosage Adjustment in Patients with Renal Impairment Significant increase in drug exposures occurred when tenofovir disoproxil fumarate tablets were administered to subjects with moderate to severe renal impairment (creatinine clearance below 50 mL/min). Table 3 provides dosage interval adjustment for patients with renal impairment. No dosage adjustment of tenofovir disoproxil fumarate tablets 300 mg is necessary for patients with mild renal impairment (creatinine clearance 50 to 80 mL/min) [see Warnings and Precautions ( 5.3 ), Use in Specific Populations ( 8.6 ), and Clinical Pharmacology ( 12.3 ) ] . Table 3 Dosage Interval Adjustment for Adult Patients with Altered Creatinine Clearance Creatinine Clearance (mL/min) a Hemodialysis Patients 50 or greater 30 to 49 10 to 29 Recommended 300 mg Dosing Interval Every 24 hours Every 48 hours Every 72 to 96 hours Every 7 days or after a total of approximately 12 hours of dialysis b a. Calculated using ideal (lean) body weight. b. Generally once weekly assuming 3 hemodialysis sessions a week of approximately 4 hours’ duration. Tenofovir disoproxil fumarate tablets should be administered following completion of dialysis. No data are available to make dosage recommendations in patients with creatinine clearance below 10 mL/min who are not on hemodialysis. No data are available to make dosage recommendations in pediatric patients with renal impairment.