Emtricitabine

Pronunciation: EM-trye-SYE-ta-been
Class: Nucleoside reverse transcriptase inhibitor

Trade Names

Emtriva
- Capsules, oral 200 mg
- Solution, oral 10 mg/mL

Pharmacology

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.

Slideshow: Flashback: FDA Drug Approvals 2013

Pharmacokinetics

Absorption

Absolute bioavailability is approximately 93% (capsules) and 75% (solution). Postdose T max approximately 1 to 2 h. Steady-state C max is approximately 1.8 mcg/mL. AUC is approximately 10 mcg•h/mL. Mean steady-state trough plasma concentration at 24 h postdose is 0.09 mcg/mL.

Distribution

In vitro binding to plasma proteins was less than 4%.

Metabolism

Oxidation of thiol moiety to form 3′-sulfoxide diastereoisomers and conjugation to form 2′-O-glucuronide.

Elimination

Plasma half-life is approximately 10 h. Eliminated in the urine (86%, with 13% as putative metabolites) and feces (14%).

Special Populations

Renal Function Impairment

C max and AUC are increased in patients with CrCl less than 50 mL/min or ESRD requiring dialysis. Dosage reduction required.

Hepatic Function Impairment

Emtricitabine is not metabolized by liver enzymes, so the impact of hepatic impairment should be limited.

Elderly

Not fully evaluated.

Children

Exposure is similar to adults. In neonates, the AUC was similar to the AUC observed in children at least 3 mo to 17 y of age.

Gender

The pharmacokinetics were similar in men and women.

Race

No pharmacokinetic differences have been identified.

Indications and Usage

In combination with other antiretroviral agents for the treatment of HIV-1 infection.

Contraindications

Hypersensitivity to any component of the product.

Dosage and Administration

Adults

PO 200 mg capsule once daily or 240 mg oral solution once daily.

Children 3 mo through 17 y of age

PO 200 mg capsules once daily for children weighing more than 33 kg and who can swallow an intact capsule or 6 mg/kg oral solution up to a max of 240 mg once daily.

Children 0 to 3 mo of age

PO 3 mg/kg once daily.

Renal Function Impairment
Adults

PO CrCl 30 to 49 mL/min, administer 200 mg capsules every 48 h or 120 mg oral solution every 24 h. CrCl 15 to 29 mL/min, administer 200 mg capsules every 72 h or 80 mg oral solution every 24 h. CrCl less than 15 mL/min or hemodialysis, administer 200 mg capsules every 96 h or 60 mg oral solution every 24 h. If dosing on day of dialysis, administer after dialysis.

Children

PO Consider a reduction in dose and/or increase in dosing interval similar to adjustments for adults.

General Advice

  • May be administered without regard to meals. Administer with food if GI upset occurs.

Storage/Stability

Store capsules at 59° to 86°F. Store solution under refrigeration at 36° to 46°F. Use solution within 3 mo if stored at 59° to 86°F.

Drug Interactions

Lamivudine

Do not coadminister with drugs containing lamivudine.

Adverse Reactions

The following adverse reactions have been reported with the use of emtricitabine in combination with 1 or more antiretroviral agents.

CNS

Dizziness (25%); headache (22%); asthenia, insomnia (16%); abnormal dreams (11%); depression, depressive disorders, fatigue (9%); paresthesia (6%); neuropathy/peripheral neuritis (4%).

Dermatologic

Hyperpigmentation (32%); rash event, including allergic reaction, maculopapular rash, pruritus, pustular rash, rash, urticaria, and vesiculobullous rash (30%).

EENT

Otitis media (23%); rhinitis (20%).

GI

Diarrhea, vomiting (23%); nausea (18%); abdominal pain (14%); gastroenteritis (11%); dyspepsia (8%).

Lab Tests

Elevated cholesterol (22%); elevated creatinine kinase (12%); elevated triglycerides (10%); increased amylase (8%); elevated AST (6%); decreased neutrophils, increased ALT (5%); abnormal glucose, hematuria (3%); elevated CPK, elevated pancreatic amylase (2%); decreased Hgb, elevated alkaline phosphatase, elevated bilirubin, elevated GGT, elevated lipase (1%).

Musculoskeletal

Myalgia (6%); arthralgia (5%).

Respiratory

Increased cough (28%); pneumonia (15%); sinusitis, upper respiratory tract infection (8%); nasopharyngitis (5%).

Miscellaneous

Infection (44%); fever (18%); anemia (7%).

Precautions

Warnings

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone and in combination with other antiretroviral agents.

Emtricitabine is not indicated for the treatment of chronic hepatitis B virus (HBV) infection. Severe acute exacerbations of HBV have been reported in patients who have discontinued emtricitabine.


Monitor

Monitor patient for signs of lactic acidosis. HBV testing is recommended prior to initiation of therapy. Closely monitor clinical response to treatment and renal function in patients with baseline CrCl less than 50 mL/min. Closely monitor hepatic function for at least several months in patients who discontinue emtricitabine or are coinfected with HIV-1 and HBV.


Pregnancy

Category B . Expected to cross placenta; however, drug should not be withheld because the expected benefit to the HIV-positive mother outweighs the unknown risk to the fetus.

Lactation

Undetermined. HIV-infected women should not breast-feed their infants.

Elderly

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

Renal Function

Dosage adjustment is recommended.

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, have occurred in patients receiving antiretroviral therapy.

Immune reconstitution syndrome

During the initial phase of treatment, patients may develop an inflammatory response to indolent or residual opportunistic infections. Autoimmune disorders have also been reported to occur in the setting of immune reconstitution.

Patient Information

  • Warn patients that this drug is not to be used by itself but is combined with other antiviral agents and not to change the dose or stop taking any of the antiretroviral agents unless advised by their health care provider.
  • Advise patients to take prescribed dose daily without regard to meals, but to take with food if stomach upset occurs.
  • Advise patients that if a dose is missed to take the dose as soon as possible and then return to the normal schedule. Do NOT take 2 doses at the same time.
  • Instruct patients to report these symptoms immediately to health care provider: difficulty breathing; fast or irregular heartbeat; feeling cold, dizzy, or light-headed; persistent nausea or vomiting; profound weakness or tiredness; unexpected stomach discomfort.
  • Inform patients that drug is not a cure for HIV and does not reduce the risk of transmitting HIV to others. Appropriate precautions must still be followed.
  • Advise patients that illnesses associated with HIV infection, including opportunistic infections, may continue to be acquired.
  • Advise HIV-infected women to not breast-feed their infants to avoid risking transmission of HIV.
  • Advise patients coinfected with HBV and HIV that severe acute exacerbations of hepatitis B have been reported when emtricitabine has been discontinued.
  • Advise patients not to take other drugs containing emtricitabine or lamivudine.
  • Advise patients that redistribution or accumulation of body fat may occur.
  • Advise patients that lactic acidosis and severe hepatomegaly with steatosis have been reported. Symptoms may include nausea, unusual or unexpected stomach discomfort, vomiting, and weakness.

Copyright © 2009 Wolters Kluwer Health.

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