TENOFOVIR DISOPROXIL FUMARATE- tenofovir disoproxil fumarate tablet
Strides Pharma Science Limited
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 in patients who dis continue 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)].
Tenofovir disoproxil fumarate is 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.
Pediatric use information is approved for Gilead Sciences, Inc.’s VIREAD® (tenofovir disoproxil fumarate) tablets. However, due to Gilead Sciences, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.
2.1 Testing Prior to Initiation of Tenofovir disoproxil fumarates for Treatment of HIV-1 Infection or Chronic Hepatitis B
Prior to or when initiating Tenofovir disoproxil fumarate, test patients for HBV infection and HIV-1 infection. Tenofovir disoproxil fumarate 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, 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 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 is the same for both HIV and HBV indications.
The recommended dosage of Tenofovir disoproxil fumarate 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 dose adjusted accordingly.
Table 1 Recommended Dosing for Patients 2 Years and Older and Weighing at Least 17 kg Using Tenofovir disoproxil fumarate
|Body Weight (kg)||Dosing of Tenofovir Disoproxil Fumarate Tablets|
|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|
Significant increase in drug exposures occurred when tenofovir disoproxil fumarate was 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 50–80 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)*||Hemodialysis Patients|
|50 or greater||30–49||10–29|
|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 †|
No data are available to make dose recommendations in pediatric patients with renal impairment.
Tenofovir disoproxil fumarate tablets 300 mg contain 300 mg of tenofovir disoproxil fumarate which is equivalent to 245 mg of tenofovir disoproxil. The tablets are white circular film coated, convex tablets engraved “TDF” on one side and plain on other side.
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.
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 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 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.
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