Product Overview
[Drug Name]
Generic Name: Entecavir Maleate Tablets
Trade Name: Tianding
English Name: Entecavir Maleate Tablets
Chinese Pinyin: Entecavir Maleate Tablets
[Properties]
This product is a film-coated tablet that appears white or off-white after removal of the coating.
[Indications]
For the treatment of chronic hepatitis B in patients with HBeAg-positive or -negative disease.
[Dosage and Administration]
Recommended dose: Adults and adolescents aged 16 years and older should take this product orally, 0.5 mg (one tablet) once daily. For patients with viremia or lamivudine-resistant mutations during lamivudine treatment, take 1.0 mg (two tablets) once daily. This product should be taken on an empty stomach (at least 2 hours before or after a meal). See the inner package insert for details.
[Adverse Reactions]
In studies conducted internationally, the most common adverse events with this product were headache, fatigue, dizziness, and nausea. Common adverse events reported by patients treated with lamivudine include 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. See the inner package insert for details.
[Contraindications]
This product is contraindicated in patients with allergies. Use with caution in patients with allergic reactions.
[Precautions]
Patients should take entecavir under the supervision of a physician and inform their physician of any new symptoms and concomitant medications. Patients should be informed that discontinuation of the drug may sometimes lead to worsening of liver disease, so changes in treatment should be made under the guidance of a physician. Please read the package insert carefully and follow the physician's instructions.
[Special Use in Special Populations]
Precautions for Children:
Safety and efficacy data for this product in children under 16 years of age have not been established.
Precautions for Pregnancy and Breastfeeding:
The effects of entecavir on pregnant women have not been adequately studied. This product should only be used after a thorough balance of potential risks and benefits to the fetus. Currently, there is no data suggesting that this product 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, its secretion in human milk remains unclear, so breastfeeding is not recommended for mothers taking this drug.
Precautions for Elderly Patients:
Due to insufficient clinical studies with 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 the risk of toxic reactions may be higher in patients with renal impairment. Because elderly patients often have decreased renal function, careful consideration should be given to drug dosage selection and renal function monitoring.
[Drug Interactions] Entecavir metabolism 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 the following human CYP450 enzymes: 1A2, 2C9, 2C19, 3A4, 3A5, and 2B6. See the inner package insert for details.
[Pharmacological Action]
This product is a guanine nucleoside analog that inhibits hepatitis B virus (HBV) polymerase. It can be phosphorylated to form an active triphosphate, which has an intracellular half-life of 15 hours. By competing with deoxyguanosine triphosphate, the natural substrate of HBV polymerase, entecavir triphosphate can inhibit all three activities of the 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 HBV DNA positive strand. Entecavir triphosphate has weak inhibitory effects on cellular alpha, beta, and delta DNA polymerases and mitochondrial gamma DNA polymerase, with Ki values ranging from 18 to greater than 160 μM.
Storage: Store in a cool, dark place.
Strength: 0.5 mg
Packaging: 7 tablets (0.5 mg)
Expiration Date: 24 months
Approval Number: National Medicine Standard H20120039
Manufacturer: Zhengda Tianqing Pharmaceutical Group Co., Ltd.
