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Drugs reference index «Emtricitabine/Tenofovir Disoproxil Fumarate»

Emtricitabine / Tenofovir Disoproxil Fumarate

Pronunciation: (EM-trye-SYE-ta-been/ten-OH-foe-vir DYE-soe-PROX-il fue-MAR-ate)Class: Nucleoside analog reverse transcriptase inhibitor combination

Trade Names:Truvada- Tablets emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg (equiv. to tenofovir disoproxil 245 mg)

Pharmacology

Emtricitabine

Inhibits activity of HIV-1 reverse transcriptase by competing with the natural substrate deoxycytidine 5-triphosphate and by being incorporated into nascent viral DNA, resulting in chain termination.

Tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate is a prodrug of tenofovir, which inhibits the activity of HIV-1 reverse transcriptase by competing with deoxyadenosine 5-triphosphate and by DNA chain termination after incorporation into DNA.

Indications and Usage

Treatment of HIV-1 infection in combination with other antiretroviral agents.

Contraindications

Standard considerations.

Dosage and Administration

Adults

PO Emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg once daily.

Renal Function ImpairmentAdults

PO

CrCl 50 mL/min or more

Give dose every 24 h.

CrCl 30 to 49 mL/min

Give dose every 48 h.

CrCl less than 30 mL/min

Do not administer.

General Advice

  • Administer without regard to meals. Administer with food if GI upset occurs.
  • If coadministering with didanosine enteric-coated tablets, administer with a light meal or under fasted conditions. If coadministering with didanosine buffered tablet, administer under fasted conditions.

Storage/Stability

Store tablets at controlled room temperature (59° to 86°F).

Drug Interactions

Atazanavir, lopinavir/ritonavir

Tenofovir concentrations may be elevated, increasing the risk of adverse reactions. The AUC and C min of atazanavir may be decreased.

Didanosine

AUC and C max of didanosine may be elevated, increasing the risk of adverse reactions (eg, neuropathy, pancreatitis).

Drugs that reduce renal function or compete for active tubular secretion (eg, acyclovir, cidofovir, ganciclovir, valacyclovir)

May increase serum concentrations of emtricitabine or tenofovir.

Lamivudine

Because of similarities between emtricitabine and lamivudine, drugs containing lamivudine should not be coadministered.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Incidences of the following adverse reactions were reported with combined use of emtricitabine/tenofovir disoproxil fumarate plus efavirenz.

CNS

Depression, fatigue (9%); dizziness (8%); headache (6%); insomnia (5%); asthenia (postmarketing).

Dermatologic

Rash (7%).

EENT

Nasopharyngitis (5%).

GI

Diarrhea, nausea (9%); vomiting (2%); abdominal pain, increased amylase, pancreatitis (postmarketing).

Genitourinary

Acute renal failure, acute tubular necrosis, Fanconi syndrome, increased creatinine, interstitial nephritis, nephrogenic diabetes insipidus, polyuria, proteinuria, proximal renal tubulopathy, renal failure, renal insufficiency (postmarketing).

Hepatic

Hepatic steatosis, hepatitis, increased liver enzymes (postmarketing).

Hypersensitivity

Allergic reactions (postmarketing).

Lab Tests

Increased fasting cholesterol (22%); increased creatine kinase (9%); increased serum amylase (8%); elevated fasting triglycerides (4%); decreased neutrophils, hematuria, increased AST (3%); hyperglycemia, increased ALT (2%); increased alkaline phosphatase (1%).

Metabolic-Nutritional

Hypokalemia, hypophosphatemia, lactic acidosis (postmarketing).

Musculoskeletal

Muscular weakness, myopathy, osteomalacia, rhabdomyolysis (postmarketing).

Respiratory

Sinusitis, upper respiratory tract infections (8%); dyspnea (postmarketing).

Precautions

Warnings

Lactic acidosis and hepatomegaly with steatosis (including fatal cases) have been reported with use of nucleoside analogues alone and in combination with other antiretroviral agents. Truvada is not indicated for the treatment of chronic hepatitis B virus (HBV) infection and the safety and efficacy have not been established in patients co-infected with HBV and HIV.

Monitor

Lactic acidosis

Monitor patient for signs of lactic acidosis. Withhold drug and notify health care provider immediately if any of the following occur: feeling cold, dizzy, or light-headed; profound weakness or tiredness; slow or irregular heartbeat; unexpected stomach discomfort; unusual muscle pain.

Calculate CrCl prior to starting therapy and as appropriate during therapy.

Pregnancy

Category B .

Lactation

Undetermined. Advise HIV-infected mothers not to breast-feed infants.

Children

Safety and efficacy not established.

Elderly

Use with caution because of greater frequency of decreased hepatic, renal, or cardiac function, and concomitant diseases or other drug therapy.

Renal Function

Dosage adjustments are recommended. Do not administer to patients with CrCl less than 30 mL/min or to patients with end-stage renal disease requiring dialysis.

Bone effects

Decreases from baseline bone mineral density at the lumbar spine and hip have been seen. Ensure that bone density monitoring is performed in HIV-infected patients with history of pathologic bone fracture or at substantial risk for osteopenia. Ensure that supplementation with calcium and vitamin D has been considered in patients with HIV-associated osteopenia or osteoporosis.

Fat redistribution

Redistribution and accumulation of body fat, including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and cushingoid appearance, may occur.

Hepatitis B

Exacerbations of hepatitis B have been reported after discontinuation of emtricitabine. It is recommended that all patients with HIV be tested for chronic HBV before initiating antiretroviral therapy. Closely monitor patients who are coinfected with HIV and HBV with both clinical and laboratory follow-up for at least several months after stopping treatment.

Renal function impairment

Dosage adjustment is recommended.

Immune reconstitution syndrome

During initial phase of treatment, patients may develop an inflammatory response to indolent or residual opportunistic infections.

Worsening renal function

Renal function impairment, including acute renal failure and Fanconi syndrome, can occur.

Overdosage

Symptoms

Limited clinical experience is available.

Patient Information

  • Advise patient or caregiver to review the patient information leaflet before starting therapy and with each refill.
  • Advise patient to take 1 tablet once daily without regard to meals, but to take with food if stomach upset occurs.
  • Instruct patient that if a dose is missed, to take it as soon as possible and then to take the next dose at the regularly scheduled time. If it is almost time for the next dose, advise patient not to take the missed dose, and to wait and take the next dose as scheduled. Caution patient not to double the next dose to catch up.
  • Warn patient that this drug is not to be used by itself, but is combined with other antiviral agents.
  • Instruct patient to report the following symptoms immediately to health care provider: abdominal swelling or enlargement; fatty diarrhea; feeling cold, dizzy, or light-headed; profound weakness or tiredness; slow or irregular heartbeat; unexpected stomach discomfort.
  • Inform patient that the drug does not completely eliminate HIV virus and, therefore, does not reduce risk of transmitting HIV to others. Appropriate precautions must still be followed.
  • Advise patient that drug is not a cure for HIV infection and that they may continue to acquire illnesses associated with HIV infection (including opportunistic infections) and should remain under a health care provider's care.
  • Advise patient with HIV-associated osteopenia or osteoporosis to discuss need for supplementation with calcium and vitamin D with health care provider
  • Advise women to notify health care provider if pregnant, planning to become pregnant, or breast-feeding. Advise HIV-infected mothers not to breast-feed to prevent infecting infants with HIV.

Copyright © 2009 Wolters Kluwer Health.