Emtricitabine and Tenofovir

Pronunciation

(em trye SYE ta been & te NOE fo veer)

U.S. Brand Names

Truvada™

Synonyms

Tenofovir and Emtricitabine

Generic Available

No

Use

Treatment of HIV infection in combination with other antiretroviral agents

Pregnancy Risk Factor

B

Pregnancy Implications

Refer to individual agents.

Lactation

Excretion in breast milk unknown/not recommended

Contraindications

Hypersensitivity to emtricitabine, tenofovir, or any component of the formulation; severe renal impairment (Clcr<30 mL/minute).

Warnings/Precautions

Not recommended as a component of a triple nucleoside regimen.

Lactic acidosis and severe hepatomegaly with steatosis have been reported with nucleoside analogues, including fatal cases; use with caution in patients with risk factors for liver disease (risk may be increased in obese patients or prolonged exposure) and suspend treatment in any patient who develops clinical or laboratory findings suggestive of lactic acidosis (transaminase elevation may/may not accompany hepatomegaly and steatosis).

Use caution in moderate renal impairment (Clcr 30-50 mL/minute); dosage adjustment required. May cause osteomalacia and/or renal toxicity; avoid concurrent therapy with other nephrotoxic drugs; monitor renal function and possible bone abnormalities during therapy. Use caution in hepatic impairment. All patients with HIV should be tested for HBV prior to initiation of treatment. Safety and efficacy during co-infection of HIV and HBV have not been established; acute, severe exacerbations of HBV have been reported following discontinuation of antiretroviral therapy. In HBV co-infected patients, monitor hepatic function closely for several months following discontinuation. Safety and efficacy have not been established in pediatric patients.

Adverse Reactions

The adverse reaction profile of combination therapy has not been established. See individual agents.

Drug Interactions

Tenofovir: Inhibits CYP1A2 (weak)

Refer to individual agents.

Ethanol/Nutrition/Herb Interactions

Food: Food decreases peak plasma concentrations, but does not alter the extent of absorption or overall systemic exposure.

Stability

Store tablets at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Mechanism of Action

Nucleoside and nucleotide reverse transcriptase inhibitor combination; emtricitabine is a cytosine analogue while tenofovir disoproxil fumarate (TDF) is an analog of adenosine 5'-monophosphate. Each drug interferes with HIV viral RNA dependent DNA polymerase resulting in inhibition of viral replication.

Pharmacodynamics/Kinetics

Refer to individual monographs.

Dosage

Adults: Oral: One tablet (emtricitabine 200 mg and tenofovir 300 mg) once daily

Dosage adjustment in renal impairment:

Clcr 30-49 mL/minute: Increase interval to every 48 hours.

Clcr<30 mL/minute or hemodialysis: Not recommended.

Administration

May be administered with or without food. If used with didanosine; refer to didanosine monograph for additional information.

Monitoring Parameters

CBC with differential, reticulocyte count, serum creatine kinase, CD4 count, HIV RNA plasma levels, renal and hepatic function tests, bone density (long-term), serum phosphorus; testing for HBV is recommended prior to the initiation of antiretroviral therapy

Patients with HIV and HVB co-infection should be monitored for several months following tenofovir discontinuation.

Dietary Considerations

May be taken without regard to meals. Consider calcium and vitamin D supplementation in patients with history of bone fracture or osteopenia.

Mental Health: Effects on Mental Status

Depression, insomnia, and dizziness are common; may cause abnormal dreams

Mental Health: Effects on Psychiatric Treatment

GI side effects are common; combined use with SSRIs (lithium or valproic acid) may produce additive effects. May cause increases in serum triglycerides; monitor in patients receiving concurrent psychotropic medication especially, clozapine, olanzapine, quetiapine, or mirtazapine. May cause glucose abnormalities; use caution with clozapine, olanzapine, quetiapine, and risperidone. May cause neutropenia; use caution with clozapine and carbamazepine.

Dosage Forms

Tablet, film coated: Emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg