Emtricitabine

BRAND NAMES:

Descovy – Emtricitabine, tenofovir, and alafenamide make up the compound. It is available as pills to treat HIV.

Truvada- It consists of emtricitabine, tenofovir, and disoproxil fumarate. It is offered as tablets. 

Odefsey-  It consists of emtricitabine, rilpivirine, and tenofovir alafenamide.

MECHANISM OF ACTION:

Emtricitabine is a cytidine analogue. The medicine acts by blocking HIV reverse transcriptase, which prevents the transcription of HIV RNA and DNA. Inhibiting reverse transcriptase stops viral RNA from being transcribed into DNA, therefore the virus is unable to integrate its DNA into host DNA and multiply utilizing host cell machinery. This decreases viral loads.

PHARMACOKINETICS:

Absorption: The bioavailability of emtricitabine capsules is 93%, while the oral solution is 75%. Talking emtricitabine with meals reduces Cmax by 29%.

Distribution: The apparent center volume of distribution is 42.3L, whereas the periphery volume is 55.4L

Metabolism: Emtricitabine is around 86% unmetabolized. Approximately 9% of a dosage is converted to 3-sulfoxide diastereomers, 4% to 2'-O-glucuronide, and a little portion to 5-flurocytosine.

Excretion: Emtricitabine is 86% recovered in urine and 14% in feces

PHARMACODYNAMICS:

Emtricitabine is a cytidine analog that competes with the natural substrate of HIV-1 reverse transcriptase for incorporation into freshly synthesized DNA, hence stopping transcription. It is injected once daily, resulting in an extended duration of activity. Patients should be advised about the danger of lactic acidosis and hepatomegaly with steatosis.

DOSAGE AND ADMINISTRATION:

The following are the strengths and formulations of emtricitabine.

Oral solutions and capsules

• 200 mg capsules 
• Oral solution (10 mg/ml)

Usually taken orally once a day, emtricitabine is used in conjunction with other antiretroviral treatments. Emtricitabine and tenofovir are combined into a pill that is taken orally. It is typically taken once a day, with or without meals. Administer tenofovir and emtricitabine daily at around the same time.

DRUG INTERACTIONS:

Drug interactions with emtricitabine include 

• Seizures or convulsions drugs – Carbamazepine, Oxcarbazepine, Phenobarbital and Phenytoin
• Stomach problem medicines-  Esomeprazole, Pantoprazole, Omeprazole, Lansoprazole, and Labeprazole
• Dexamethasone
• Lumacaftor and Ivacaftor
• Rifampin      
• Rifapentine
• Anti-cancer- Interleukin-2
• Anti-biotic- Vancomycin, Erythromycin and Clarithromycin
• Methadone

CONTRAINDICATIONS:

Patients with an allergy to any constituent of emtricitabine should avoid taking this drug. Emtricitabine combined with tenofovir as pre-exposure prophylaxis is contraindicated as monotherapy for patients with a positive HIV status. This monotherapy can lead to HIV drug resistance to antiretroviral therapy. Emtricitabine alone has not demonstrated any significant drug interactions. PrEP treatment is also contraindicated in combination with high-dose NSAIDs acyclovir, valcyclovir, cidofovir, and aminoglycosides.

SIDE EFFECTS:

Side effects of emtricitabine may include

• Inflammation in face, lips, tongue, or throat
• Bone pain
• muscle pain
• stomach pain
• trouble breathing
• fatigue
• Fever
• cough 
• Decrease of urine
• swelling in the ankles, hands, or feet
• loss of appetite
• Nausea
• weakness 
• Diarrhea
• Light-colored stool
• yellow or brown urine
• Jaundice
• Dizziness
• Headache

OVERDOSE:

Overdose of emtricitabine includes

• Weakness or tiredness
• Unusual muscle pain
• Shortness of breath or fast breathing
• Stomach pain with nausea and vomiting
• Cold or blue hands or feet
• Dizziness
• Fast or abnormal heartbeat

TOXICITY:

Emtricitabine overdose results in toxicity. Hepatotoxicity with steatosis and lactic acidosis are signs of emtricitabine toxicity. Use supportive and symptomatic treatments, such as hemodialysis, to treat overdose.

STORAGE:

Keep the capsules at room temperature in a covered container away from heat and sunlight. Store the oral liquid in the refrigerator.