Ricovir EM Tablets(Emtricitabine (200mg) Tenofovir Disoproxil Fumarate (300mg)

Summary

Ricovir EM-Emtricitabine Combine with Tenofovir Disoproxil Fumarate is a nucleoside reverse transcriptase inhibitor used for the treatment and prophylaxis of HIV.

Buy Now

Generic Name - Emtricitabine

Background

Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) indicated for the treatment of HIV infection in adults5 or combined with tenofovir alafenamide for the prevention of HIV-1 infection in high-risk adolescents and adults. Emtricitabine is a cytidine analogue. The drug works by inhibiting HIV reverse transcriptase, preventing transcription of HIV RNA to DNA.

Emtricitabine was granted FDA approval on 2 July 2003.

Structure - Emtricitabine

---

Structure - Tenofovir

Indication

Emtricitabine is indicated in combination with other medications for the treatment of HIV-1 infections; treatment of HIV-1 infections in pediatric patients 25-35kg, treatment of HIV-1 infections in adult patients ≥35kg, for pre-exposure prophylaxis of HIV-1 in adolescent and adult patients excluding those who have receptive vaginal sex; treatment of HIV-1 infections in pediatric and adult patients ≥17kg, pre-exposure prophylaxis in adolescents and adults ≥35kg; treatment of HIV-1 in patients ≥12 years and ≥35kg;10 treatment of HIV-1 in patients weighing ≥35kg; treatment of HIV-1 in patients weighing ≥25kg; and treatment of HIV-1 in patients weighing ≥40kg.

Pharmacodynamics

Emtricitabine is a cytidine analog that competes with the natural substrate of HIV-1 reverse transcriptase to be incorporated into newly formed DNA, terminating its transcription. It is administered once daily so it has a long duration of action. Patients should be counselled regarding the risk of lactic acidosis and hepatomegaly with steatosis.

Mechanism of action

Emtricitabine is a cytidine analog that, when phosphorylated to emtricitabine 5'-triphosphate, competes with deoxycytidine 5'-triphosphate for HIV-1 reverse transcriptase. As HIV-1 reverse transcriptase incorporates emtricitabine into forming DNA strands, new nucleotides are unable to be incorporated, leading to viral DNA chain termination. Inhibition of reverse transcriptase prevents transcription of viral RNA into DNA, therefore the virus is unable to incorporate its DNA into host DNA and replicate using host cell machinery. This reduces viral load.

Absorption

Emtricitabine reaches a Cmax of 1.8±0.7µg/mL with a Tmax of 1-2 hours and has an AUC of 10±3.1µg*hr/mL. The bioavailability of emtricitabine capsules is 93% and the bioavailability of the oral solution is 75%.5 Taking emtricitabine with food decreases the Cmax by 29%.[L9019]

Volume of distribution

The apparent central volume of distribution is 42.3L and the peripheral volume of distribution is 55.4L.

Protein binding

Emtricitabine is <4% bound to plasma proteins, mainly serum albumin.

Metabolism

Emtricitabine is approximately 86% unmetabolized. Approximately 9% of a dose is metabolized to 3'-sulfoxide diastereomers, 4% to the 2'-O-glucuronide, and a minor amount is converted to 5-fluorocytosine.

Route of elimination

Emtricitabine is 86% recovered in the urine and 14% recovered in feces. 13% of the dose is recovered in the urine as metabolites; 9% as 3'-sulfoxide diastereomers and 4% as 2'-O-glucuronide.

Half-life

The half-life of emtricitabine is approximately 10 hours.

Clearance

Emtricitabine has an apparent elimination rate of 15.1L/h.2 This rate is closely linked to creatinine clearance.

Toxicity

The LD50 of emtricitabine is not readily available.[9019, L9818]

Symptoms of emtricitabine toxicity include hepatotoxicity with steatosis, as well as lactic acidosis. Treat overdose with symptomatic and supportive measures, including hemodialysis.

Food Interactions

• Take with or without food. The absorption is unaffected by food.