emtricitabine and tenofovir disoproxil fumarate

emtricitabine and tenofovir disoproxil fumarate

Truvada

Pharmacologic class: Nucleoside/nucleotide reverse-transcriptase inhibitor combination

Therapeutic class: Antiretroviral

Pregnancy risk category B

Action

Inhibits activity of human immunodeficiency virus-1 (HIV-1) reverse transcriptase by competing with natural substrate and by its incorporation into nascent viral DNA, thereby halting viral replication. Tenofovir disoproxil fumarate inhibits activity of HIV-1 reverse transcriptase by competing with the natural substrate deoxyadenosine 5′-triphosphate and by its incorporation into viral DNA, resulting in chain termination.

Availability

Tablets: 200 mg emtricitabine/300 mg tenofovir disoproxil fumarate

⊘Indications and dosages

➣ HIV-1 infection in adults

Adults: 1 tablet P.O. daily

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:
• renal impairment
• increased risk of lactic acidosis or hepatic impairment
• decreased bone density
• obese patients
• elderly patients
• children (safety and efficacy not established).

Administration

• Give with or without food.
• Don't give with drug products containing lamivudine.
• Know that drug is usually given with other antiretrovirals.

Route	Onset	Peak	Duration
P.O.	Rapid	1-2 hr	Unknown

Adverse reactions

CNS: headache, insomnia, abnormal dreams, asthenia, dizziness, depressive disorder, neuropathy, peripheral neuropathy, peripheral neuritis, paresthesia

CV: chest pain

EENT: rhinitis

GI: nausea, vomiting, diarrhea, abdominal pain, anorexia, dyspepsia, flatulence, pancreatitis

GU: hematuria, glycosuria, proteinuria, proximal tubulopathy, renal insufficiency, acute tubular necrosis, renal failure, acute renal failure, Fanconi syndrome

Hepatic: hepatotoxicity

Metabolic: cushingoid appearance (buffalo hump, moon face), hypophosphatemia, lactic acidosis

Musculoskeletal: arthralgia, myalgia, back pain

Respiratory: dyspnea, increased cough, pneumonia

Skin: sweating, rash, pruritus, urticaria, skin discoloration (hyperpigmentation of palms and soles)

Other: weight loss, fever, allergic reaction, body fat redistribution

Interactions

Drug-drug. Acyclovir, adefovir dipivoxil, cidofovir, ganciclovir, valacyclovir, valganciclovir: increased concentration of emtricitabine/tenofovir

Atazanavir, lopinavir/ritonavir: increased tenofovir concentration

Didanosine: increased didanosine concentration

Drug-diagnostic tests. Alanine phosphatase, amylase, aspartate aminotransferase, bilirubin, creatine kinase, creatinine, lipase, urine and serum glucose: increased levels

Neutrophils: decreased count

Patient monitoring

☞ Monitor patient closely (especially female or obese patient) for signs and symptoms of lactic acidosis and hepatotoxicity, even if patient doesn't have marked transaminase elevations.
• Assess neurologic status, especially for depression, peripheral neuropathy, and paresthesia.
• Monitor neutrophil count, lipid panel, liver function test results, and blood glucose level.
• Monitor renal function closely, especially if patient is receiving nephrotoxic agents.
☞ Monitor patient closely for several months after drug withdrawal. Severe, acute exacerbations of hepatitis B virus (HBV) have been reported after discontinuation in patients co-infected with HBV and HIV.
• Monitor nutritional and hydration status in light of GI adverse effects and underlying disease.
• Watch for cushingoid appearance and body fat redistribution.

Patient teaching

☞ Instruct patient not to change dosage or stop taking drug unless prescriber approves.
☞ Advise patient to immediately report signs or symptoms of lactic acidosis - unusual tiredness or muscle pain, difficulty breathing, stomach pain with nausea and vomiting, coldness, dizziness or light-headedness, and fast or irregular heartbeat.
☞ Instruct patient to immediately report signs and symptoms of liver problems - unusual tiredness, yellowing of skin or eyes, dark urine, light-colored feces, appetite loss, nausea, and lower abdominal pain.
• Advise patient to notify prescriber of adverse CNS reactions and to use good judgment about driving and other hazardous activities.
• Inform patient that drug may cause depression. Tell him to notify prescriber if he develops symptoms.
• Inform patient that drug may cause body fat redistribution, rash, and dark areas on palms and soles.
• Advise patient to tell prescriber if he has bone problems before taking drug.
• Tell female patient to inform prescriber if she is pregnant or plans to become pregnant.
• Caution HIV-positive patient not to breastfeed.
• If patient misses a dose, instruct him to take it as soon as he remembers. However, if it's almost time for next dose, tell him to skip the missed dose and take next dose as scheduled.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.