Vemlidy Tenofovir alafenamide fumarate tablets

1. Indications and Usage
Tenofovir alafenamide fumarate tablets are indicated for the treatment of chronic hepatitis B virus (HBV) infection in adults and adolescents aged 12 years and older weighing at least 35 kg.
2. Dosage and Administration
Recommended Dosage: The recommended dose is 25 mg once daily.
Administration: Tablets should be taken orally once daily with food.
Missed Dose: If a dose is missed and less than 18 hours have passed, take the missed dose as soon as possible. If more than 18 hours have passed, do not take the missed dose; return to the regular schedule.
Vomiting: If vomiting occurs within 1 hour of taking a dose, take another dose. If vomiting occurs after 1 hour, no additional dose is needed.
Renal Impairment: No dosage adjustment is required for patients with creatinine clearance (CrCl) ≥15 mL/min or those on hemodialysis (administer post-dialysis). No dosage recommendation exists for patients with CrCl <15 mL/min not on hemodialysis.
3. Mechanism of Action
Tenofovir alafenamide is a prodrug of tenofovir, an adenine nucleotide analog. It enters cells and is metabolized to tenofovir, which is then phosphorylated to tenofovir diphosphate. This active metabolite inhibits HBV reverse transcriptase and HIV-1 reverse transcriptase, thereby blocking viral replication.
4. Safety and Warnings
Hepatic Effects: Severe acute exacerbations of hepatitis have been reported in patients who discontinued tenofovir alafenamide.
Immune Reconstitution: Severe exacerbations of hepatitis may occur following the initiation of anti-HIV therapy due to immune reconstitution.
Renal and Bone Effects: New or worsening renal impairment, and decreases in bone mineral density, have been reported with tenofovir-containing regimens.
5. Adverse Reactions and Clinical Research
Common Adverse Reactions: According to the National Medical Products Administration, the most frequently reported adverse reactions are headache, nausea, fatigue, diarrhea, and abdominal pain。
Clinical Research: Clinical trials have demonstrated that tenofovir alafenamide effectively suppresses HBV DNA and HIV-1 RNA while showing a more favorable renal and bone safety profile compared to tenofovir disoproxil fumarate.
6. Drug Interactions
Contraindicated Drugs: Tenofovir alafenamide should not be used with medicines containing tenofovir disoproxil, tenofovir alafenamide, or adefovir.
P-gp and BCRP Inducers: Drugs that induce P-gp and breast cancer resistance protein (BCRP), such as rifampin, may lower tenofovir alafenamide plasma concentrations and reduce efficacy.
P-gp and BCRP Inhibitors: Drugs that inhibit these transporters may increase plasma concentrations.
Nephrotoxic Drugs: Concomitant use with other nephrotoxic drugs may increase the risk of renal toxicity.
7. Pharmaceutical Information
Composition: The active ingredient is tenofovir alafenamide fumarate.
Appearance: Film-coated tablets, typically yellow and round.
Storage: Store at controlled room temperature and protect from moisture.