TENOFOVIR DISOPROXIL FUMARATE (Page 4 of 10)
Based on published data, tenofovir has been shown to be present in human breast milk (see Data). It is not known if tenofovir affects milk production or has effects on the breastfed child.
Treatment of HIV-1 infection:
The Centers for Disease Control and Prevention recommend that HIV-1 infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV-1.
Because of the potential for: (1) HIV transmission (in HIV-negative infants); (2) developing viral resistance (in HIV-positive infants); and (3) adverse reactions in a breastfed infant similar to those seen in adults, instruct mothers not to breastfeed if they are taking tenofovir disoproxil fumarate for the treatment of HIV-1.
Treatment of HBV infection:
The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for tenofovir disoproxil fumarate and any potential adverse effects on the breastfed infant from tenofovir disoproxil fumarate or from the underlying maternal condition.
In a study of 50 HIV-uninfected, breastfeeding women on a tenofovir-containing regimen initiated between 1 and 24 weeks postpartum (median 13 weeks), tenofovir was undetectable in the plasma of most infants after 7 days of treatment in mothers. There were no serious adverse events in mothers or infants.
8.4 Pediatric Use
Pediatric Patients 2 Years and Older with HIV-1 infection
The safety and effectiveness of tenofovir disoproxil fumarate in pediatric patients 2 years to less than 18 years of age is supported by data from two randomized trials. Trial 352 was a randomized controlled trial in 92 HIV-1 treatment experienced subjects 2 years to less than 12 years of age who were virologically suppressed on a stavudine- or zidovudine-containing regimen and were randomized to either switch to a tenofovir disoproxil fumarate -containing regimen (N=44) or stay on their original regimen (N=48) for 48 weeks. At Week 48, 89% of subjects in the tenofovir disoproxil fumarate treatment group and 90% of subjects in the d4T or AZT treatment group had HIV-1 RNA concentrations <400 copies/mL. Trial 321 was a placebo-controlled trial in 87 HIV-1 treatment experienced subjects 12 years to less than 18 years of age who were treated with tenofovir disoproxil fumarate (N=45) or placebo (N=42) in combination with an optimized background regimen for 48 weeks. Overall, the trial failed to show a difference in virologic response between the tenofovir disoproxil fumarate and placebo groups. Subgroup analyses suggest the lack of difference in virologic response may be attributable to imbalances between treatment arms in baseline viral susceptibility to tenofovir disoproxil fumarate and OBR [see Adverse Reactions (6.1) and Clinical Studies (14.3)].
Although changes in HIV-1 RNA in these highly treatment-experienced subjects in Trial 321 were less than anticipated, the pharmacokinetic profile of tenofovir in patients 2 years to less than 18 years of age at the recommended doses was similar to that found to be safe and effective in adult clinical trials [see Clinical Pharmacology (12.3)].
The effects of tenofovir disoproxil fumarate -associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in HIV-1 pediatric patients 2 years and older are unknown. The long- term effect of lower spine and total body BMD on skeletal growth in pediatric patients 2 years and older, and in particular, the effects of long-duration exposure in younger children is unknown [see Warnings and Precautions (5.5), Adverse Reactions (6.1)].
Safety and effectiveness of tenofovir disoproxil fumarate in pediatric patients younger than 2 years of age and weighing less than 10 kg with HIV-1 infection have not been established.
Pediatric Patients 12 Years of Age and Older with Chronic Hepatitis B
The safety and effectiveness of tenofovir disoproxil fumarate in pediatric patients 12 years to less than 18 years of age is supported by data from one randomized trials (Trial 115) in which tenofovir disoproxil fumarate was administered to HBV-infected treatment-experienced subjects .
In Trial 115, 106 HBeAg negative (9%) and positive (91%) subjects 12 years to less than 18 years of age with chronic HBV infection were randomized to receive blinded treatment with tenofovir disoproxil fumarate or placebo for 72 weeks. At Week 72, 88% of subjects in the tenofovir disoproxil fumarate group and 0% of subjects in the placebo group had HBV DNA <400 copies/mL (69 IU/mL).
The effects of tenofovir disoproxil fumarate -associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in chronic HBV-infected pediatric patients 2 years and older are unknown. The long-term effect of lower spine and total body BMD on skeletal growth in pediatric patients 2 years and older, and in particular, the effects of long-duration exposure in younger children is unknown [see Warnings and Precautions (5.5), Adverse Reactions (6.1)].
Safety and effectiveness of tenofovir disoproxil fumarate in chronic HBV-infected pediatric patients younger than 2 years of age and weighing less than 10 kg have not been established.
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
8.5 Geriatric Use
Clinical trials of tenofovir disoproxil fumarate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for the elderly patient should be cautious, keeping in mind the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
8.6 Renal Impairment
The dosing interval for tenofovir disoproxil fumarate should be modified in adult patients with estimated creatinine clearance below 50 mL/min or in patients with end stage renal disease requiring dialysis [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3)].
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, a four-hour hemodialysis session removed approximately 10% of the administered tenofovir dose.
Tenofovir disoproxil fumarate (a prodrug of tenofovir) is a fumaric acid salt of bisisopropoxycarbonyloxymethyl ester derivative of tenofovir. In vivo tenofovir disoproxil fumarate is converted to tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5′-monophosphate.
Tenofovir exhibits activity against HIV-1 reverse transcriptase.
The chemical name of tenofovir disoproxil fumarate is 9-[( R)-2-[[bis[[(isopropoxycarbonyl)oxy]methoxy]phosphinyl]methoxy]propyl]adenine fumarate (1:1). It has a molecular formula of C 19 H 30 N 5 O 10 P • C 4 H 4 O 4 and a molecular weight of 635.52. It has the following structural formula:
Tenofovir disoproxil fumarate is a white to off-white crystalline powder with a solubility of 13.4 mg/mL in distilled water at 25 °C. It has an octanol/phosphate buffer (pH 6.5) partition coefficient (log p) of 1.25 at 25 °C.
Tenofovir disoproxil fumarate is available as tablets.
Tenofovir disoproxil fumarate tablets are for oral administration in strength of 300 mg of tenofovir disoproxil fumarate, which is equivalent to 245 mg of tenofovir disoproxil. Each tablet contains the following inactive ingredients: croscarmellose sodium, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and pregelatinized starch. The tablets are coated with Opadry White Y-1-7000 , which contains Hypromellose, Titanium dioxide USP & Polyethylene glycol 400 (Macrogol) USP.
In this insert, all dosages are expressed in terms of tenofovir disoproxil fumarate except where otherwise noted.
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