Product Overview
[Drug Name]
Generic Name: Entecavir Dispersible Tablets
Trade Name: Runzhong
English Name: Entecavir Dispersible Tablets
Chinese Pinyin: Entikawei FensanPian
[Ingredients]
The main ingredient of this product is: Entecavir. Chemical Name: 2-Amino-9-[(1S,3R,4S)-4-hydroxy-3-hydroxymethyl-2-methylenecyclopentyl]-1,9-dihydro-6H-purin-6-one monohydrate. Chemical Structure: Molecular Formula: C₁₂H₁₅N₅O₃H₂O. Molecular Weight: 295.3
[Properties]
This product is a white or off-white tablet.
[Indications]
This product is indicated for the treatment of chronic hepatitis B in adults with active viral replication, persistently elevated serum ALT, or active liver histological lesions.
[Dosage and Administration]
This product should be taken under the guidance of an experienced physician. Recommended Dose: Adults and adolescents 16 years and older should take 0.5 mg orally once daily. Patients who develop viremia or lamivudine-resistant mutations during lamivudine treatment should take 1 mg (two 0.5 mg tablets) once daily. This product should be taken on an empty stomach (at least 2 hours before or after a meal).
[Adverse Reactions]
In international studies, the most common adverse events with this product were headache, fatigue, dizziness, and nausea. Common adverse events in patients treated with lamivudine were headache, fatigue, and dizziness. In these four studies, 1% of entecavir-treated patients and 4% of lamivudine-treated patients withdrew from the study due to adverse events and abnormal laboratory test results, respectively.
[Contraindications]
This product is contraindicated in patients with allergies to any component of the active entecavir formulation.
[Precautions]
1. Patients should take entecavir under the guidance of a physician and inform their physician of any new symptoms and concomitant medications. 2. Patients should be informed that discontinuation of entecavir may sometimes lead to worsening of liver disease, and therefore should change their treatment under the guidance of a physician. 3. Treatment with entecavir does not reduce the risk of HBV transmission through sexual contact or contaminated blood. Therefore, appropriate protective measures should be taken, and liver function tests should be monitored regularly during treatment.
[Use in Special Populations]
Precautions for Children:
Safety and efficacy data for this drug in children under 16 years of age have not been established.
Precautions for Pregnancy and Breastfeeding:
Studies on the effects of entecavir on pregnant women are inadequate. This drug should only be used after a thorough balance of potential risks and benefits for the fetus has been made. Currently, there are no data suggesting that this drug can affect mother-to-child transmission of HBV. Therefore, appropriate interventions should be implemented to prevent neonatal HBV infection. Entecavir is secreted in rat milk. However, whether it is secreted in human milk remains unknown. Therefore, breastfeeding is not recommended for mothers taking this drug.
Precautions for Elderly Patients:
Due to the lack of sufficient clinical studies of patients aged 65 years and older, it is unclear whether elderly patients respond differently to this drug compared to younger patients. Other clinical trial reports have also not found differences between elderly and younger patients. Entecavir is primarily excreted by the kidneys, and patients with renal impairment may be at increased risk of toxic reactions. Because elderly patients often have decreased renal function, careful dosing and renal function monitoring are essential.
[Drug Interactions]
The metabolism of entecavir has been evaluated in vitro and in vivo. Entecavir is not a substrate, inhibitor, or inducer of the cytochrome P450 (CYP450) enzyme system. At concentrations approximately 10,000 times the human concentration, entecavir does not inhibit any of the major human CYP450 enzymes: 1a2, 2c9, 2c19, 2d6, 3a4, 2b6, and 2e1. At concentrations approximately 340 times the human concentration, entecavir does not induce any of the major human CYP450 enzymes: 1a2, 2c9, 2c19, 3a4, 3a5, and 2b6. Concomitant administration of drugs that are metabolized by inhibitors or inducers of the CYP450 system has no effect on the pharmacokinetics of entecavir. Furthermore, coadministration of entecavir has no effect on the pharmacokinetics of known CYP substrates. Studies of the interaction between entecavir and lamivudine, adefovir, and tenofovir revealed no alterations in the steady-state pharmacokinetics of either entecavir or the interacting drugs. Because entecavir is primarily eliminated through the kidneys, concurrent administration of entecavir with drugs that reduce renal function or compete for active glomerular secretion may increase the plasma concentrations of these drugs. Coadministration of entecavir with lamivudine, adefovir, or tenofovir does not result in significant drug interactions. The interaction of entecavir with other drugs that are eliminated through the kidneys or are known to affect renal function has not been studied. Patients should be closely monitored for adverse reactions when coadministering entecavir with such drugs.
[Pharmacology]
This product is a guanine nucleoside analog that inhibits hepatitis B virus (HBV) polymerase. It is phosphorylated to its active triphosphate, which has an intracellular half-life of 15 hours. By competing with the natural substrate of HBV polymerase, deoxyguanosine triphosphate, entecavir triphosphate inhibits all three activities of viral polymerase (reverse transcriptase): (1) initiation of HBV polymerase; (2) formation of the reverse transcriptase negative strand of pregenomic mRNA; and (3) synthesis of the positive strand of HBV DNA. Entecavir triphosphate has a weak inhibitory effect on cellular α, β, and δ DNA polymerases and mitochondrial γ DNA polymerase, with KI values ranging from 18 to greater than 160 μM.
[Storage】Sealed and stored in a dry place.
[Specification] 0.5 mg * 7 tablets
[Packaging Specification] Box
[Expiration Period] 36 months
[Approval Number] National Medicine Standard H20100019
[Manufacturer] Company Name: Zhengda Tianqing Pharmaceutical Group Co., Ltd.
