emtricitabine

em·tri·cit·a·bine (mtr-st-bn, -st-)

n.

A nucleoside analog used to treat HIV infection in combination with other antiretroviral drugs.

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emtricitabine

Emtriva

Pharmacologic class: Nucleoside reverse transcriptase inhibitor

Therapeutic class: Antiretroviral

Pregnancy risk category B

FDA Boxed Warning

• Drug has caused lactic acidosis and severe hepatomegaly with steatosis (including fatal cases) when used alone or in combination with other antiretrovirals.
• Drug isn't indicated for chronic hepatitis B virus (HBV) infection. Safety and efficacy haven't been established in patients co-infected with HBV and human immunodeficiency virus (HIV). Discontinuation has led to severe acute HBV exacerbations. Monitor hepatic function closely.

Action

Inhibits activity of HIV-1 reverse transcriptase by competing with natural substrate and by its incorporation into nascent viral DNA, thereby halting viral replication

Availability

Capsules: 200 mg

Oral solution: 10 mg/ml in 170-ml bottles

⊘Indications and dosages

➣ HIV-1 infection, with other antiretrovirals

Adults ages 18 and older: 200-mg capsule P.O. daily or 240 mg (24 ml) oral solution P.O. once daily

Children ages 3 months to 17 years weighing more than 33 kg (73 lb): 200-mg capsule P.O. once daily

Children ages 3 months to 17 years weighing less than 33 kg (73 lb): 6 mg/kg oral solution P.O. daily to maximum of 240 mg (24 ml) once daily

Children ages 0 to 3 months: 3 mg/kg oral solution P.O. once daily

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug or its components

Precautions

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

Administration

• Give with or without food.
• Know that drug must be given with other antiretrovirals.
• Know that capsule can be given to child weighing more than 33 kg if child can swallow an intact capsule.

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

Adverse reactions

CNS: dizziness, headache, insomnia, abnormal dreams, depression, peripheral neuritis or neuropathy, paresthesia

EENT: rhinitis

GI: nausea, vomiting, diarrhea, abdominal pain, dyspepsia

Hepatic: hepatotoxicity

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

Musculoskeletal: joint pain, myalgia

Respiratory: increased cough

Skin: rash, skin discoloration (hyperpigmentation on palms and soles)

Other: body fat redistribution

Interactions

Drug-drug. Tenofovir disoproxil fumarate: increased emtricitabine effect

Drug-diagnostic tests. Alanine aminotransferase, amylase, aspartate aminotransferase, bilirubin, creatine kinase, lipase, triglycerides: increased levels

Glucose: increased or decreased level

Neutrophils: decreased count

Patient monitoring

☞ Monitor closely (especially in females and obese patients) for signs and symptoms of lactic acidosis and hepatotoxicity, even if patient doesn't have marked transaminase elevations.
• Assess neurologic status, checking especially for depression, peripheral neuropathy, and paresthesia.
• Monitor neutrophil count, lipid panel, liver function tests, and blood glucose level.
☞ 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

• Tell patient to take a missed dose 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.
☞ Instruct patient not to change dosage or stop taking drug unless prescriber approves.
• Tell patient drug should be taken only in combination with other drugs that treat HIV.
☞ Instruct patient not to take this drug if already taking Altripla (combination of efavirenz, emtricitabine, and tenofovir), Combivir (combination of lamivudine and zidovudine), Epivir (lamivudine), Epzicom (combination of abacavir and lamivudine), Trizivir (combination of abacavir, lamivudine, and zidovidine), or Truvada (combination of emtricitabine and tenofovir), because these drugs contain the same or similar ingredients.
☞ Tell 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, or fast or irregular heartbeat.
☞ Instruct patient to immediately report signs or symptoms of liver problems - unusual tiredness, yellowing of skin or eyes, dark urine, light-colored feces, appetite loss, nausea, or pain in lower abdominal area.
• Advise patient to report adverse CNS reactions and to use good judgment about driving and other hazardous activities.
• Caution patient that drug may cause depression. Tell him to notify prescriber if he develops symptoms.
• Inform patient that drug may cause body fat redistribution, dark areas on palms and soles, and rash.
• Tell female patient to inform prescriber if she is pregnant or plans to become pregnant.
• Caution HIV-positive patient not to breastfeed.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.