Patients with Impaired Renal Function
It is recommended that the dose or dosing interval for Emtriva be modified in patients with creatinine clearance less than 50 mL/min or in patients who require dialysis [See Dosage and Administration (2.5)].

Overdosage
There is no known antidote for Emtriva. Limited clinical experience is available at doses higher than the therapeutic dose of Emtriva. In one clinical pharmacology trial single doses of emtricitabine 1200 mg were administered to 11 subjects. No severe adverse reactions were reported.

The effects of higher doses are not known. If overdose occurs the patient should be monitored for signs of toxicity, and standard supportive treatment applied as necessary.

Hemodialysis treatment removes approximately 30% of the emtricitabine dose over a 3-hour dialysis period starting within 1.5 hours of emtricitabine dosing (blood flow rate of 400 mL/min and a dialysate flow rate of 600 mL/min). It is not known whether emtricitabine can be removed by peritoneal dialysis.

Emtriva Description
Emtriva is the brand name of emtricitabine, a synthetic nucleoside analog with activity against human immunodeficiency virus type 1 (HIV-1) reverse transcriptase.

The chemical name of emtricitabine is 5-fluoro-1-(2R,5S)-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine. Emtricitabine is the (-) enantiomer of a thio analog of cytidine, which differs from other cytidine analogs in that it has a fluorine in the 5-position.

It has a molecular formula of C8H10FN3O3S and a molecular weight of 247.24. It has the following structural formula:

Emtricitabine is a white to off-white powder with a solubility of approximately 112 mg/mL in water at 25 °C. The log P for emtricitabine is -0.43 and the pKa is 2.65.

Emtriva is available as capsules or as an oral solution.

Emtriva capsules are for oral administration. Each capsule contains 200 mg of emtricitabine and the inactive ingredients crospovidone, magnesium stearate, microcrystalline cellulose, povidone, titanium dioxide, gelatin, and FD&C blue No. 2.

Emtriva oral solution is for oral administration. One milliliter (1 mL) of Emtriva oral solution contains 10 mg of emtricitabine in an aqueous solution with the following inactive ingredients: cotton candy flavor, FD&C yellow No. 6, edetate disodium, methylparaben and propylparaben (added as preservatives), sodium phosphate (monobasic), propylene glycol, water, and xylitol (added as a sweetener). Sodium hydroxide and hydrochloric acid may be used to adjust pH.

Emtriva - Clinical Pharmacology
Mechanism of Action
Emtricitabine is an antiviral drug [See Clinical Pharmacology (12.4)].

Pharmacokinetics
Adults

The pharmacokinetics of emtricitabine were eva luated in healthy subjects and HIV-1-infected subjects. Emtricitabine pharmacokinetics are similar between these populations.

Figure 1 shows the mean steady-state plasma emtricitabine concentration-time profile in 20 HIV-1-infected subjects receiving Emtriva capsules.

Figure 1 Mean (± 95% CI) Steady-State Plasma Emtricitabine Concentrations in HIV-1-Infected Adults (N=20)

Absorption

Emtricitabine is rapidly and extensively absorbed following oral administration with pea