TRUVADA tablets are fixed-dose combination tablets containing emtricitabine and tenofovir disoproxil fumarate. Emtricitabine is a synthetic nucleoside analog of cytidine. Tenofovir DF is converted in vivo to tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5′-monophosphate. Both emtricitabine and tenofovir exhibit inhibitory activity against HIV-1 reverse transcriptase. Emtricitabine: The chemical name of emtricitabine is 5-fluoro-1-(2 R ,5 S )-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine. Emtricitabine is the (-) enantiomer of a thio analog of cytidine, which differs from other cytidine analogs in that it has a fluorine in the 5-position. It has a molecular formula of C 8 H 10 FN 3 O 3 S and a molecular weight of 247.24. It has the following structural formula: Emtricitabine is a white to off-white crystalline powder with a solubility of approximately 112 mg/mL in water at 25 °C. The partition coefficient (log p) for emtricitabine is -0.43 and the pKa is 2.65. Chemical Structure Tenofovir Disoproxil Fumarate: Tenofovir disoproxil fumarate is a fumaric acid salt of the bis-isopropoxycarbonyloxymethyl ester derivative of tenofovir. 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 water at 25 °C. The partition coefficient (log p) for tenofovir disoproxil is 1.25 and the pKa is 3.75. All dosages are expressed in terms of tenofovir disoproxil fumarate except where otherwise noted. TRUVADA tablets are for oral administration, and are available in the following strengths: Film-coated tablet containing 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate (which is equivalent to 245 mg of tenofovir disoproxil) as active ingredients Film-coated tablet containing 167 mg of emtricitabine and 250 mg of tenofovir disoproxil fumarate (which is equivalent to 204 mg of tenofovir disoproxil) as active ingredients Film-coated tablet containing 133 mg of emtricitabine and 200 mg of tenofovir disoproxil fumarate (which is equivalent to 163 mg of tenofovir disoproxil) as active ingredients Film-coated tablet containing 100 mg of emtricitabine and 150 mg of tenofovir disoproxil fumarate (which is equivalent to 123 mg of tenofovir disoproxil) as active ingredients All strength of TRUVADA tablets also include the following inactive ingredients: croscarmellose sodium, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and pregelatinized starch (gluten free). The 200 mg/300 mg strength tablets are coated with Opadry II Blue Y-30-10701, which contains FD&C Blue #2 aluminum lake, hypromellose 2910, lactose monohydrate, titanium dioxide, and triacetin. The 167 mg/250 mg, 133 mg/200 mg, and 100 mg/150 mg strength tablets are coated with Opadry II Blue, which contains FD&C Blue #2 aluminum lake, hypromellose 2910, lactose monohydrate, titanium dioxide, and triacetin. Chemical Structure

TRUVADA is a combination of EMTRIVA and VIREAD, both nucleoside analog HIV-1 reverse transcriptase inhibitors. TRUVADA is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults and pediatric patients weighing at least 17 kg. TRUVADA is indicated in combination with safer sex practices for pre-exposure prophylaxis (PrEP) to reduce the risk of sexually acquired HIV-1 in adults at high risk

Treatment of HIV-1 Infection TRUVADA ® , a combination of EMTRIVA ® and VIREAD ® , is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults and pediatric patients weighing at least 17 kg . The following points should be considered when initiating therapy with TRUVADA for the treatment of HIV-1 infection:The following points should be considered when initiating therapy with TRUVADA for the treatment of HIV-1 infection: It is not recommended that TRUVADA be used as a component of a triple nucleoside regimen. TRUVADA should not be coadministered with ATRIPLA ® , COMPLERA ® , EMTRIVA, GENVOYA ® , ODEFSEY ® , STRIBILD ® , VIREAD or lamivudine-containing products . In treatment experienced patients, the use of TRUVADA should be guided by laboratory testing and treatment history

Pre-Exposure Prophylaxis TRUVADA is indicated in combination with safer sex practices for pre-exposure prophylaxis (PrEP) to reduce the risk of sexually acquired HIV-1 in adults at high risk. This indication is based on clinical trials in men who have sex with men (MSM) at high risk for HIV-1 infection and in heterosexual serodiscordant couples . When considering TRUVADA for pre-exposure prophylaxis the following factors may help to identify individuals at high risk: has partner(s) known to be HIV-1 infected, or engages in sexual activity within a high prevalence area or social network and one or more of the following: inconsistent or no condom use diagnosis of sexually transmitted infections exchange of sex for commodities (such as money, food, shelter, or drugs) use of illicit drugs or alcohol dependence incarceration partner(s) of unknown HIV-1 status with any of the factors listed above When prescribing TRUVADA for pre-exposure prophylaxis, healthcare providers must: prescribe TRUVADA as part of a comprehensive prevention strategy because TRUVADA is not always effective in preventing the acquisition of HIV-1 infection ; counsel all uninfected individuals to strictly adhere to the recommended TRUVADA dosing schedule because the effectiveness of TRUVADA in reducing the risk of acquiring HIV-1 was strongly correlated with adherence as demonstrated by measurable drug levels in clinical trials ; confirm a negative HIV-1 test immediately prior to initiating TRUVADA for a PrEP indication. If clinical symptoms consistent with acute viral infection are present and recent (<1 month) exposures are suspected, delay starting PrEP for at least one month and reconfirm HIV-1 status or use a test approved by the FDA as an aid in the diagnosis of HIV-1 infection, including acute or primary HIV-1 infection ; and screen for HIV-1 infection at least once every 3 months while taking TRUVADA for PrEP.

TRUVADA tablets are available in four dose strengths: Tablet: 100 mg of emtricitabine and 150 mg of tenofovir disoproxil fumarate (equivalent to 123 mg of tenofovir disoproxil): blue, oval-shaped, film-coated, debossed with "GSI" on one side and with "703" on the other side. Tablet: 133 mg of emtricitabine and 200 mg of tenofovir disoproxil fumarate (equivalent to 163 mg of tenofovir disoproxil): blue, rectangular-shaped, film-coated, debossed with "GSI" on one side and with "704" on the other side. Tablet: 167 mg of emtricitabine and 250 mg of tenofovir disoproxil fumarate (equivalent to 204 mg of tenofovir disoproxil): blue, modified capsule-shaped, film-coated, debossed with "GSI" on one side and with "705" on the other side. Tablet: 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate (equivalent to 245 mg of tenofovir disoproxil): blue, capsule-shaped, film-coated, debossed with "GILEAD" on one side and with "701" on the other side. Tablets: 200 mg/300 mg, 167 mg/250 mg, 133 mg/200 mg, and 100 mg/150 mg of emtricitabine and tenofovir disoproxil fumarate, respectively.

Treatment of HIV-1 Infection Recommended dose in adults and pediatric patients weighing greater than or equal to 35 kg: One TRUVADA tablet (containing 200 mg/300 mg of emtricitabine and tenofovir disoproxil fumarate) once daily taken orally with or without food. Recommended dose in pediatric patients weighing greater than or equal to 17 kg and able to swallow a whole tablet: one TRUVADA low strength tablet (100 mg/150 mg, 133 mg/200 mg, or 167 mg/250 mg based on body weight) once daily taken orally with or without food. Recommended dose in renally impaired HIV-1 infected adult patients: Creatinine clearance 30–49 mL/min: 1 tablet every 48 hours. CrCl below 30 mL/min or hemodialysis: Do not use TRUVADA. Pre-exposure Prophylaxis Recommended dose in HIV-1 uninfected adults: One tablet (containing 200 mg/300 mg of emtricitabine and tenofovir disoproxil fumarate) once daily taken orally with or without food. Recommended dose in renally impaired HIV-uninfected individuals: Do not use TRUVADA in HIV-uninfected individuals if CrCl is below 60 mL/min. If a decrease in CrCl is observed in uninfected individuals while using TRUVADA for PrEP, evaluate potential causes and re-assess potential risks and benefits of continued use

Recommended Dose for Treatment of HIV-1 Infection in Adults and Pediatric Patients Weighing 35 Kg or More The recommended dose of TRUVADA in adults and in pediatric patients with body weight greater than or equal to 35 kg is one tablet (containing 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate) once daily taken orally with or without food

Recommended Dose for Treatment of HIV-1 Infection in Pediatric Patients Weighing at Least 17 kg and Able to Swallow a Whole Tablet The recommended oral dose for pediatric patients weighing greater than or equal to 17 kg and who are able to swallow a whole tablet, is one TRUVADA low strength tablet (emtricitabine [FTC]/tenofovir disoproxil fumarate [TDF]) (167 mg/250 mg, 133 mg/200 mg, or 100 mg/150 mg based on body weight) taken orally once daily with or without food. The recommended oral dosage of TRUVADA low strength tablets is presented in Table 1. Weight should be monitored periodically and the TRUVADA dose adjusted accordingly. Table 1 Dosing for Pediatric Patients Weighing 17 kg to less than 35 kg using TRUVADA Low Strength Tablets Body Weight (kg) Dosing of FTC (mg)/TDF (mg) 17 to less than 22 one 100/150 tablet once daily 22 to less than 28 one 133/200 tablet once daily 28 to less than 35 one 167/250 tablet once daily 2.3 Recommended Dose for Pre-exposure Prophylaxis The dose of TRUVADA in HIV-1 uninfected adults is one tablet (containing 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate) once daily taken orally with or without food

Dose Adjustment for Renal Impairment Treatment of HIV-1 Infection Significantly increased drug exposures occurred when EMTRIVA or VIREAD were administered to subjects with moderate to severe renal impairment . Therefore, adjust the dosing interval of TRUVADA in HIV-1 infected adult patients with baseline creatinine clearance 30–49 mL/min using the recommendations in Table 2. These dosing interval recommendations are based on modeling of single-dose pharmacokinetic data in non-HIV infected subjects. The safety and effectiveness of these dosing interval adjustment recommendations have not been clinically evaluated in patients with moderate renal impairment, therefore clinical response to treatment and renal function should be closely monitored in these patients . No dose adjustment is necessary for HIV-1 infected patients with mild renal impairment (creatinine clearance 50–80 mL/min). No data are available to make dose recommendations in pediatric patients with renal impairment. Table 2 Dosage Adjustment for HIV-1 Infected Adult Patients with Altered Creatinine Clearance Creatinine Clearance (mL/min) Calculated using ideal (lean) body weight ≥50 30–49 <30 (Including Patients Requiring Hemodialysis) Recommended Dosing Interval Every 24 hours Every 48 hours TRUVADA should not be administered. Routine monitoring of estimated creatinine clearance, serum phosphorus, urine glucose, and urine protein should be performed in all individuals with mild renal impairment . Pre-exposure Prophylaxis Do not use TRUVADA for a PrEP indication in HIV-1 uninfected individuals with estimated creatinine clearance below 60 mL/min . Routine monitoring of estimated creatinine clearance, serum phosphorus, urine glucose, and urine protein should be performed in all individuals with mild renal impairment. If a decrease in estimated creatinine clearance is observed in uninfected individuals while using TRUVADA for PrEP, evaluate potential causes and re-assess potential risks and benefits of continued use .

New onset or worsening renal impairment: Can include acute renal failure and Fanconi syndrome. Assess estimated creatinine clearance before initiating treatment with TRUVADA. In patients at risk for renal dysfunction, assess estimated creatinine clearance, serum phosphorus, urine glucose and urine protein before initiating treatment with TRUVADA and periodically during treatment. Avoid administering Truvada with concurrent or recent use of nephrotoxic drugs. Coadministration with Other Products: Do not use with drugs containing emtricitabine, tenofovir alafenamide or tenofovir disoproxil fumarate including ATRIPLA, COMPLERA, EMTRIVA, GENVOYA, ODEFSEY, STRIBILD, VIREAD; or with drugs containing lamivudine. Do not administer in combination with HEPSERA. 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. Redistribution/accumulation of body fat: Observed in patients receiving antiretroviral therapy. Immune reconstitution syndrome: May necessitate further evaluation and treatment. Triple nucleoside-only regimens: Early virologic failure has been reported in HIV-infected patients. Monitor carefully and consider treatment modification. Comprehensive management to reduce the risk of acquiring HIV-1: Use as part of a comprehensive prevention strategy including other prevention measures; strictly adhere to dosing schedule. Management to reduce the risk of acquiring HIV-1 drug resistance: Prior to initiating TRUVADA for PrEP - if clinical symptoms consistent with acute viral infection are present and recent (<1 month) exposures are suspected, delay starting PrEP for at least one month and reconfirm negative HIV-1 status or use a test approved by the FDA as an aid in the diagnosis of HIV-1 infection, including acute or primary HIV-1 infection. While using TRUVADA for PrEP - HIV-1 screening tests should be repeated at least every 3 months. 5.1 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 VIREAD, a component of TRUVADA, in combination with other antiretrovirals. A majority of these cases have been in women. Obesity and prolonged nucleoside exposure may be risk factors. Particular caution should be exercised when administering nucleoside analogs to any patient or uninfected individual with known risk factors for liver disease; however, cases have also been reported in HIV-1 infected patients with no known risk factors. Treatment with TRUVADA should be suspended in any patient or uninfected individual 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)

HBV Infection It is recommended that all individuals be tested for the presence of chronic hepatitis B virus (HBV) before initiating TRUVADA. TRUVADA is not approved for the treatment of chronic HBV infection and the safety and efficacy of TRUVADA have not been established in patients infected with HBV. Severe acute exacerbations of hepatitis B have been reported in patients who are coinfected with HBV and HIV-1 and have discontinued TRUVADA. In some patients infected with HBV and treated with EMTRIVA, the exacerbations of hepatitis B were associated with liver decompensation and liver failure. Patients who are infected with HBV should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment with TRUVADA. If appropriate, initiation of anti-hepatitis B therapy may be warranted. HBV-uninfected individuals should be offered vaccination

New Onset or Worsening Renal Impairment Emtricitabine and tenofovir are 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 VIREAD . It is recommended that estimated creatinine clearance be assessed in all individuals prior to initiating therapy and as clinically appropriate during therapy with TRUVADA. In patients at risk of renal dysfunction, including patients who have previously experienced renal events while receiving HEPSERA ® , it is recommended that estimated creatinine clearance, serum phosphorus, urine glucose, and urine protein be assessed prior to initiation of TRUVADA, and periodically during TRUVADA therapy. TRUVADA should be avoided with concurrent or recent use of a nephrotoxic agent (e.g., high-dose or multiple non-steroidal anti-inflammatory drugs (NSAIDs)) . 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 tenofovir disoproxil fumarate (tenofovir DF). 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 at-risk patients. Treatment of HIV-1 Infection Dosing interval adjustment of TRUVADA and close monitoring of renal function are recommended in all patients with estimated creatinine clearance 30–49 mL/min . No safety or efficacy data are available in patients with renal impairment who received TRUVADA using these dosing guidelines, so the potential benefit of TRUVADA therapy should be assessed against the potential risk of renal toxicity. TRUVADA should not be administered to patients with estimated creatinine clearance below 30 mL/min or patients requiring hemodialysis. Pre-exposure Prophylaxis TRUVADA for a PrEP indication should not be used if estimated creatinine clearance is less than 60 mL/min. If a decrease in estimated creatinine clearance is observed in uninfected individuals while using TRUVADA for PrEP, evaluate potential causes and re-assess potential risks and benefits of continued use

Coadministration with Other Products TRUVADA is a fixed-dose combination of emtricitabine and tenofovir disoproxil fumarate. Do not coadminister TRUVADA with other drugs containing emtricitabine or tenofovir disoproxil fumarate, or containing tenofovir alafenamide, including ATRIPLA, COMPLERA, EMTRIVA, GENVOYA, ODEFSEY, STRIBILD, or VIREAD. Due to similarities between emtricitabine and lamivudine, do not coadminister TRUVADA with other drugs containing lamivudine, including Combivir (lamivudine/zidovudine), Dutrebis (lamivudine/raltegravir) , Epivir or Epivir-HBV (lamivudine), Epzicom (abacavir sulfate/lamivudine), Triumeq (abacavir sulfate/dolutegravir/lamivudine), or Trizivir (abacavir sulfate/lamivudine/zidovudine). Do not coadminister TRUVADA with HEPSERA (adefovir dipivoxil) Do not coadminister TRUVADA with HEPSERA (adefovir dipivoxil)

Bone Effects of Tenofovir DF Bone Mineral Density: In clinical trials in HIV-1 infected adults and in a clinical trial of HIV-1 uninfected individuals, tenofovir DF 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 . Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher in subjects receiving tenofovir DF. Clinical trials evaluating tenofovir DF in pediatric and adolescent subjects were conducted. Under normal circumstances, BMD increases rapidly in pediatric patients. In HIV-1 infected subjects aged 2 years to less than 18 years, bone effects were similar to those observed in adult subjects and suggest increased bone turnover. Total body BMD gain was less in the tenofovir DF treated HIV-1 infected pediatric subjects as compared to the control groups. Similar trends were observed in chronic hepatitis B infected adolescent subjects aged 12 years to less than 18 years. In all pediatric trials, skeletal growth (height) appeared to be unaffected. For more information, consult the VIREAD prescribing information. The effects of tenofovir DF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk are unknown. 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. Although the effect of supplementation with calcium and vitamin D was not studied, such supplementation may be beneficial. If bone abnormalities are suspected then 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 the use of tenofovir DF . Arthralgias 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 products containing tenofovir DF

Fat Redistribution Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and "cushingoid appearance" have been observed in HIV-1 infected patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established

Immune Reconstitution Syndrome Immune reconstitution syndrome has been reported in HIV-1 infected patients treated with combination antiretroviral therapy, including TRUVADA. 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, Pneumocystis 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

Early Virologic Failure Clinical trials in HIV-1 infected subjects have demonstrated that certain regimens that only contain three nucleoside reverse transcriptase inhibitors (NRTI) are generally less effective than triple drug regimens containing two NRTIs in combination with either a non-nucleoside reverse transcriptase inhibitor or a HIV-1 protease inhibitor. In particular, early virologic failure and high rates of resistance substitutions have been reported. Triple nucleoside regimens should therefore be used with caution. Patients on a therapy utilizing a triple nucleoside-only regimen should be carefully monitored and considered for treatment modification

Comprehensive Management to Reduce the Risk of Acquiring HIV-1 Use TRUVADA for pre-exposure prophylaxis only as part of a comprehensive prevention strategy that includes other prevention measures, such as safer sex practices, because TRUVADA is not always effective in preventing the acquisition of HIV-1 . Counsel uninfected individuals about safer sex practices that include consistent and correct use of condoms, knowledge of their HIV-1 status and that of their partner(s), and regular testing for other sexually transmitted infections that can facilitate HIV-1 transmission (such as syphilis and gonorrhea). Inform uninfected individuals about and support their efforts in reducing sexual risk behavior. Use TRUVADA to reduce the risk of acquiring HIV-1 only in individuals confirmed to be HIV-negative. HIV-1 resistance substitutions may emerge in individuals with undetected HIV-1 infection who are taking only TRUVADA, because TRUVADA alone does not constitute a complete treatment regimen for HIV-1 treatment ; therefore, care should be taken to minimize drug exposure in HIV-infected individuals. Many HIV-1 tests, such as rapid tests, detect anti-HIV antibodies and may not identify HIV-1 during the acute stage of infection. Prior to initiating TRUVADA for a PrEP indication, evaluate seronegative individuals for current or recent signs or symptoms consistent with acute viral infections (e.g., fever, fatigue, myalgia, skin rash, etc.) and ask about potential exposure events (e.g., unprotected, or condom broke during sex with an HIV-1 infected partner) that may have occurred within the last month. If clinical symptoms consistent with acute viral infection are present and recent (<1 month) exposures are suspected, delay starting PrEP for at least one month and reconfirm HIV-1 status or use a test approved by the FDA as an aid in the diagnosis of HIV-1 infection, including acute or primary HIV-1 infection. While using TRUVADA for a PrEP indication, HIV-1 screening tests should be repeated at least every 3 months. If symptoms consistent with acute HIV-1 infection develop following a potential exposure event, PrEP should be discontinued until negative infection status is confirmed using a test approved by the FDA as an aid in the diagnosis of HIV-1, including acute or primary HIV-1 infection. Counsel uninfected individuals to strictly adhere to the recommended TRUVADA dosing schedule. The effectiveness of TRUVADA in reducing the risk of acquiring HIV-1 is strongly correlated with adherence as demonstrated by measurable drug levels in clinical trials .

No drug interaction trials have been conducted using TRUVADA tablets. Drug interaction trials have been conducted with emtricitabine and tenofovir disoproxil fumarate, the components of TRUVADA. This section describes clinically relevant drug interactions observed with emtricitabine and tenofovir disoproxil fumarate . Didanosine: Tenofovir disoproxil fumarate increases didanosine concentrations. Use with caution and monitor for evidence of didanosine toxicity (e.g., pancreatitis, neuropathy) when coadministered. Consider dose reductions or discontinuations of didanosine if warranted. HIV-1 protease inhibitors: Coadministration decreases atazanavir concentrations and increases tenofovir concentrations. When coadministered with TRUVADA, use atazanavir given with ritonavir. Coadministration of TRUVADA with atazanavir and ritonavir, darunavir and ritonavir, or lopinavir/ritonavir increases tenofovir concentrations. Monitor for evidence of tenofovir toxicity

Didanosine Coadministration of TRUVADA and didanosine should be undertaken with caution and patients receiving this combination should be monitored closely for didanosine-associated adverse reactions. Didanosine should be discontinued in patients who develop didanosine-associated adverse reactions. When tenofovir disoproxil fumarate was administered with didanosine the C max and AUC of didanosine increased significantly . The mechanism of this interaction is unknown. 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 DF with didanosine 400 mg daily. In patients weighing greater than 60 kg, the didanosine dose should be reduced to 250 mg when it is coadministered with TRUVADA. Data are not available to recommend a dose adjustment of didanosine for adult or pediatric patients weighing less than 60 kg. When coadministered, TRUVADA and Videx EC may be taken under fasted conditions or with a light meal (less than 400 kcal, 20% fat)

HIV-1 Protease Inhibitors Tenofovir decreases the AUC and C min of atazanavir . When coadministered with TRUVADA, it is recommended that atazanavir 300 mg is given with ritonavir 100 mg. TRUVADA should not be coadministered with atazanavir without ritonavir . Lopinavir/ritonavir, atazanavir coadministered with ritonavir, and darunavir coadministered with ritonavir have been shown to increase tenofovir concentrations . Tenofovir disoproxil fumarate is a substrate of P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) transporters. When tenofovir disoproxil fumarate is co-administered with an inhibitor of these transporters, an increase in absorption may be observed. Patients receiving TRUVADA concomitantly with lopinavir/ritonavir, ritonavir-boosted atazanavir, or ritonavir-boosted darunavir should be monitored for tenofovir disoproxil fumarate-associated adverse reactions. TRUVADA should be discontinued in patients who develop tenofovir disoproxil fumarate-associated adverse reactions

Hepatitis C Antiviral Agents Coadministration of tenofovir disoproxil fumarate and HARVONI ® (ledipasvir/sofosbuvir) has been shown to increase tenofovir exposure . In patients receiving TRUVADA concomitantly with HARVONI without an HIV-1 protease inhibitor/ritonavir or an HIV-1 protease inhibitor/cobicistat combination, monitor for adverse reactions associated with tenofovir disoproxil fumarate. In patients receiving TRUVADA 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 tenofovir disoproxil fumarate

Drugs Affecting Renal Function Emtricitabine and tenofovir are primarily excreted by the kidneys by a combination of glomerular filtration and active tubular secretion . No drug-drug interactions due to competition for renal excretion have been observed; however, coadministration of TRUVADA with drugs that are eliminated by active tubular secretion may increase concentrations of emtricitabine, tenofovir, and/or the coadministered drug. Some examples include, but are not limited to, acyclovir, adefovir dipivoxil, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs . Drugs that decrease renal function may increase concentrations of emtricitabine and/or tenofovir.