Product Overview
[Drug Name]
Generic Name: Entecavir Capsules
Trade Name: Engandin
English Name: Entecavir Capsules
Chinese Pinyin: EnTiKaWeiJiaoNang
[Ingredients]
The main ingredient is entecavir. Chemical Name: 2-Amino-9-[(1S,3R,4S)-4-hydroxy-3-hydroxymethyl-2-methylenecyclopentyl]-1,9-dihydro-6H-purin-6-one monohydrate. Molecular Weight: C12H15N5O3H2O
[Properties]
This product consists of white or off-white granules or powder.
[Indications]
This product is indicated for the treatment of chronic hepatitis B in adults with active viral replication, persistently elevated serum alanine aminotransferase (ALT), or active liver histological lesions.
[Dosage and Administration]
This product should be taken under the guidance of an experienced physician. 1. Recommended Dose: Adults and adolescents 16 years of age and older should take 0.5 mg orally once daily. 2. Renal Impairment: In patients with renal impairment, the oral clearance of entecavir decreases with decreasing creatinine clearance. The dose should be adjusted for patients with creatinine clearance <50 ml/min (including those receiving hemodialysis or CAPD). 1) For patients with creatinine clearance ≥50 ml/min, the usual dose is 0.5 mg once daily. For patients who have failed lamivudine (1.0 mg), the usual dose is 1.0 mg once daily. 2) For patients with creatinine clearance 30 to 50 ml/min, the usual dose is 0.25 mg once daily. For patients who have failed lamivudine (1.0 mg), the usual dose is 0.5 mg once daily. 3) For patients with creatinine clearance 10 to 30 ml/min, the usual dose is 0.15 mg once daily. For patients who have failed lamivudine (1.0 mg), the usual dose is 0.3 mg once daily. 4) After hemodialysis or CAPD, the usual dose is 0.05 mg once daily. For patients who have failed lamivudine (1.0 mg), the dose is 0.1 mg once daily. 3. Hepatic Impairment: No dose adjustment is required for patients with hepatic impairment. 4. Treatment Period: The optimal duration of treatment with this drug and its relationship with long-term treatment outcomes, such as cirrhosis and liver cancer, are currently unknown.
[Adverse Reactions]
1. In international studies, the most common adverse events with this drug were headache, fatigue, dizziness, and nausea. 2. Common adverse events in patients treated with lamivudine were headache, fatigue, and dizziness. In these four studies, 1% of patients treated with entecavir and 4% of patients treated with lamivudine withdrew from the study due to adverse events and abnormal laboratory test results.
[Contraindications]
Entecavir is contraindicated in patients with allergies to entecavir or any of the ingredients in the formulation.
[Precautions]
Patients with renal impairment should carefully read the package insert and use according to their physician's instructions.
[Use in Special Populations]
Precautions for Children:
Safety and efficacy data for this drug in children under 18 years of age have not been established.
Precautions for Pregnancy and Lactation:
The effects of entecavir on pregnant women are inadequately studied. This drug should only be used after a thorough balance of potential risks and benefits for the fetus. Currently, there are no data suggesting that this drug affects 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 unclear. Therefore, breastfeeding is not recommended for mothers taking this drug.
Precautions for Elderly:
Due to the lack of sufficient clinical studies involving patients aged 65 years and older, it is unclear whether responses to this drug differ between elderly and younger patients. Other clinical trial reports have not found differences between elderly and younger patients. Entecavir is primarily excreted by the kidneys, and the risk of toxic reactions may be higher in patients with renal impairment. Because elderly patients often have decreased renal function, careful dosing and renal function monitoring are important. Drug Interactions: Entecavir's metabolism was 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 did 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 did not induce the following human CYP450 enzymes: 1A2, 2C9, 2C19, 3A4, 3A5, and 2B6. Concomitant administration of drugs that inhibit or induce the CYP450 system had no effect on the pharmacokinetics of entecavir. Furthermore, concomitant administration of entecavir did not affect the pharmacokinetics of known CYP substrates.
[Pharmacological Actions]
This product is a guanine nucleoside analog that inhibits hepatitis B virus (HBV) polymerase. It can be phosphorylated to form an active triphosphate, and the half-life of the triphosphate in the cell is 15 hours. By competing with the natural substrate of HBV polymerase, deoxyguanosine triphosphate, entecavir triphosphate can inhibit all three activities of viral polymerase (reverse transcriptase): (1) initiation of HBV polymerase; (2) formation of the negative strand of pregenomic mRNA reverse transcription; and (3) synthesis of the positive strand of HBV DNA. The inhibition constant (Ki) of entecavir triphosphate on HBV DNA polymerase is 0.0012M. Entecavir triphosphate has a weak inhibitory effect on cellular α, β, δ DNA polymerase and mitochondrial γ DNA polymerase, with Ki values ranging from 18 to greater than 160uM. Antiviral activity In human HepG2 cells transfected with wild-type hepatitis B virus, the concentration required for entecavir to inhibit 50% viral DNA synthesis (EC50) is 0.004uM.
[Storage]Store in a dark and sealed place.
[Strength] 0.5mg
[Packaging] Aluminum-plastic blister pack, 7 tablets per sheet
[Expiration Date] 24 months
[Approval Number] National Medicine Standard H20110172
[Manufacturer] Fujian Guangshengtang Pharmaceutical Co., Ltd.
