emtricitabine/tenofovir disoproxil fumarate

Contraindicated in:

Unknown or positive HIV status (for PrEP);
Severe renal impairment (HIV treatment) (CCr <30 mL/min);
Moderate or severe renal impairment (PrEP) (CCr <60 mL/min);
Lactation: Breastfeeding should be avoided in mothers infected with HIV.

Use Cautiously in:

Hepatitis B virus (HBV) (may lead to acute exacerbation of HBV upon discontinuation);
Moderate renal impairment (CCr 30–49 mL/min) (adjust dosing interval);
History of pathologic fractures/osteoporosis/bone loss;
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk (in women with HIV, monitor viral load closely);
Pedi: Safety and effectiveness not established in children who weigh <17 kg (HIV treatment) or <35 kg (PrEP).

Adv. Reactions/Side Effects ⬆ ⬇

F and E: hypophosphatemia

GI: ↑liver enzymes, abdominal pain, autoimmune hepatitis, LACTIC ACIDOSIS/HEPATOMEGALY WITH STEATOSIS, POST-TREATMENT ACUTE EXACERBATION OF HEPATITIS B

GU: ACUTE RENAL FAILURE/FANCONI SYNDROME, renal impairment

Metab: ↓weight

MS: ↓bone mineral density, bone pain, muscle pain, osteomalacia, polymyositis

Neuro: Guillain-Barré syndrome, headache

Misc: immune reconstitution syndrome

Interactions ⬆ ⬇

Drug-drug:

Nephrotoxic agents, including NSAIDs, ↑ risk of nephrotoxicity; avoid concurrent use.
Other drugs eliminated by active tubular secretion, including acyclovir, adefovir, aminoglycosides, cidofovir, ganciclovir, valacyclovir, and valganciclovir, may ↑ levels.
May ↓ atazanavir levels and effectiveness; administer atazanavir with ritonavir when used with emtricitabine/tenofovir disoproxil fumarate.
Lopinavir/ritonavir, atazanavir/ritonavir, or darunavir/ritonavir may ↑ tenofovir levels and risk of toxicity; closely monitor.
Sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, or ledipasvir/sofosbuvir may ↑ tenofovir levels and risk of toxicity; closely monitor.

Availability ⬆ ⬇

(Generic available)

Tablets: emtricitabine 100 mg/tenofovir disoproxil fumarate 150 mg; emtricitabine 133 mg/tenofovir disoproxil fumarate 200 mg; emtricitabine 167 mg/tenofovir disoproxil fumarate 250 mg; emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg

Route/Dosage ⬆ ⬇

HIV-1 Infection

PO (Adults and Children ≥35 kg): One tablet (emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) once daily.
PO (Children 28–<35 kg): One tablet (emtricitabine 167 mg/tenofovir disoproxil fumarate 250 mg) once daily.
PO (Children 22–<28 kg): One tablet (emtricitabine 133 mg/tenofovir disoproxil fumarate 200 mg) once daily.
PO (Children 17–<22 kg): One tablet (emtricitabine 100 mg/tenofovir disoproxil fumarate 150 mg) once daily.

Renal Impairment

PO (Adults ≥35 kg): CCr 30–49 mL/min: One tablet (emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) every 48 hr. CCr <30 mL/min (including hemodialysis): Not recommended.

HIV-1 PrEP

PO (Adults and Children ≥35 kg): One tablet (emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) once daily.

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Emtricitabine and tenofovir disoproxil fumarate: Phosphorylated intracellularly where it inhibits HIV reverse transcriptase, resulting in inhibition of viral replication.

Therapeutic effects:

Slowed progression of HIV infection and decreased occurrence of sequelae.
Reduction in risk of sexually acquired HIV infection in at-risk individuals.

Classifications ⬆ ⬇

Therapeutic Classification: antiretrovirals

Pharmacologic Classification: nucleoside reverse transcriptase inhibitors

Pharmacokinetics ⬆ ⬇

Emtricitabine

Absorption: Rapidly and extensively absorbed (93% bioavailable).

Distribution: Unknown

Metabolism/Excretion: Undergoes some metabolism with 86% renally excreted and 14% excreted in feces as metabolites.

Half-Life: 10 hr

Tenofovir Disoproxil Fumarate

Absorption: Tenofovir disoproxil fumarate is a prodrug and undergoes hydrolysis to be converted to tenofovir, the active component

Distribution: Unknown.

Metabolism/Excretion: 70–80% excreted unchanged in urine by glomerular filtration and active tubular secretion.

Half-Life: 17 hr.

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
Emtricitabine PO	rapid	1–2 hr	24 hr
Tenofovir PO	rapid	1–2 hr	24 hr

Patient/Family Teaching ⬆ ⬇

Emphasize the importance of taking Truvada as directed. Do not take more than prescribed amount and do not stop taking without consulting health care professional. Uninfected individuals who miss doses are at greater risk of acquiring HIV-1. Advise patient to read Medication Guide prior to starting therapy and with each Rx refill in case of changes.
Advise patients taking Truvada for HIV-1 PrEP to only take Truvada if confirmed HIV-1 negative. Some HIV-1 tests can miss HIV-1 infection in patients recently infected. Notify health care professional if flu-like symptoms (tiredness, fever, joint or muscle aches, headache, sore throat, vomiting or diarrhea, rash, night sweats, enlarged lymph nodes in the neck or groin) occur. Advise patient to use condoms consistently and correctly to lower chances of sexual contact with any body fluids (semen, vaginal secretions, blood), the importance of knowing their HIV-1 status and the HIV-1 status of their partner(s), the need to get tested at least every 3 mo or more frequently for HIV-1 and other sexually transmitted infections (syphilis, chlamydia, gonorrhea), and to ask their partner to get tested. Advise patient if they become HIV-1 positive, more antiretroviral medication than Truvada is needed to treat HIV-1.
Advise patients taking Truvada to treat HIV-1 infection that Truvada alone is not a complete treatment for HIV-1; other antiretroviral medications are required.
Instruct patient that Truvada should not be shared with others.
Inform patient that Truvada does not cure AIDS or prevent other sexually transmitted infections, associated or opportunistic infections. Truvada may reduce the risk of transmission of HIV to others through sexual contact or blood contamination. Caution patient to use a condom and to avoid sharing needles or donating blood to prevent spreading HIV to others.
Advise patient to notify health care professional immediately if signs and symptoms of lactic acidosis (nausea, vomiting, unusual or unexpected stomach discomfort, and weakness) or severe liver problems (yellow skin or white part of eyes, dark "tea-colored" urine, light-colored stools, loss of appetite, nausea, stomach-area pain) occur.
Immune reconstitution syndrome may trigger opportunistic infections or autoimmune disorders (Graves’ disease, polymyositis, Guillain-Barré syndrome, autoimmune hepatitis). Notify health care professional if symptoms (signs and symptoms of an infection or inflammation) occur.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: Advise patient to notify health care professional if pregnancy is planned or suspected. Advise patient to avoid breastfeeding during Truvada therapy. Encourage women who become pregnant during Truvada therapy to join the Antiretroviral Pregnancy Registry that monitors pregnancy outcomes in women exposed to Truvada during pregnancy. Enroll patient by calling 1-800-258-4263.
Emphasize the importance of regular follow-up exams and blood counts to determine progress and monitor for side effects.

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Indications ⬇

Contraind./Precautions ⬆ ⬇