Product Overview
[Drug Name]
Generic Name: Adefovir Dipivoxil Tablets
Trade Name: Ding He
English Name: Adefovir Dipivoxil Tablets
Chinese Pinyin: Adefuweizhi Pian
[Ingredients]
The main ingredient is adefovir dipivoxil.
[Properties]
This product is an off-white tablet.
[Indications]
This product is indicated for the treatment of adult patients with chronic hepatitis B who have active hepatitis B virus replication and persistently elevated serum aminotransferase levels with decompensated liver function.
[Dosage and Administration]
Patients must use Dipivoxil under the guidance of a physician experienced in treating chronic hepatitis B. The recommended dose for adults (18-65 years) is 10 mg once daily, taken orally before or after meals. The optimal duration of treatment has not been determined. Do not exceed the recommended dose. Patients should regularly monitor hepatitis B biochemical, virological, and serum markers at least every six months.
[Adverse Reactions]
Common adverse reactions in international clinical studies included asthenia, headache, abdominal pain, nausea, flatulence, diarrhea, and dyspepsia. Adverse reactions in domestic clinical studies included mild leukopenia, mild diarrhea, and moderate alopecia. One serious adverse event occurred in the clinical study: a case of acute myeloid leukemia M3 after 29 weeks of treatment with adefovir, which the investigators determined was unrelated to adefovir.
[Contraindications]
Adefovir dipivoxil is contraindicated in patients with confirmed hypersensitivity to any component of adefovir.
[Precautions]
1. Acute exacerbation of hepatitis B may occur if patients discontinue hepatitis B treatment, including adefovir dipivoxil. Therefore, patients who discontinue hepatitis B treatment should closely monitor liver function and, if necessary, resume anti-hepatitis B treatment.
2. Chronic treatment with adefovir dipivoxil can cause nephrotoxicity in patients with renal impairment or at risk of renal impairment. In these patients, renal function should be closely monitored and the dose adjusted appropriately. 3. Before treatment with adefovir dipivoxil, all patients should be tested for human immunodeficiency virus (HIV) antibodies. Use of anti-hepatitis B drugs, such as adefovir dipivoxil, can affect unknown or untreated HIV in patients with chronic hepatitis B, potentially leading to HIV resistance.
4. Nucleoside analogs, used alone or in combination with other antiretroviral drugs, can cause lactic acidosis and severe hepatomegaly with steatosis, including fatal events.
5. Because the risk to the developing human embryo is unknown, women of childbearing potential treated with adefovir dipivoxil are advised to use effective contraception.
[Use in Special Populations]
Precautions for use in children:
The efficacy and safety of Hevivir in patients under 18 years of age have not been established (see [Precautions] - Other). Adefovir dipivoxil should not be used in children and adolescents.
Precautions for use during pregnancy and lactation:
Pregnancy: There are insufficient data on the use of adefovir dipivoxil in pregnant women. Animal studies of intravenous adefovir have shown reproductive toxicity (see [Pharmacology and Toxicology] - Clinical Safety Data). Pregnant women should avoid the use of adefovir dipivoxil if possible. If it is necessary, the risks and benefits should be weighed. Adefovir dipivoxil should be considered during pregnancy only if the potential benefits clearly outweigh the risks to the fetus. There are currently no data on the effect of adefovir dipivoxil on mother-to-child transmission of HBV. Therefore, infant immunization should be administered according to standard recommendations to prevent neonatal HBV infection. Because the potential risk to the developing human embryo is unknown, women of childbearing age treated with adefovir dipivoxil are advised to use effective contraceptive measures. Lactation: It is not known whether adefovir is excreted in human breast milk. Therefore, mothers taking adefovir dipivoxil should be advised not to breastfeed.
Precautions for Elderly Patients:
The efficacy and safety of Hevivir in patients over 65 years of age have not been established (see [Precautions] - Other).
[Drug Interactions]
Adefovir dipivoxil is rapidly converted to adefovir in the body. At concentrations significantly higher than those observed in vivo (>4000-fold), adefovir did not inhibit any of the following common human CYP450 enzymes: CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Adefovir is not a substrate for these enzymes. However, it is unknown whether adefovir induces CYP450 enzymes. Based on in vitro results and the renal elimination pathway of adefovir, the potential for CYP450-mediated drug interactions with other drugs, either as inhibitors or substrates, is low. Adefovir is excreted through the kidneys via glomerular filtration and active tubular secretion. Coadministration of 10 mg of adefovir dipivoxil with other drugs that are secreted through the renal tubules or that alter renal tubular secretion may increase serum concentrations of adefovir dipivoxil or the coadministered drug. Coadministration of 10 mg of adefovir dipivoxil with 100 mg of lamivudine did not alter the pharmacokinetic properties of either drug. Caution should be exercised when coadministering 10 mg of adefovir dipivoxil with drugs actively secreted by the renal tubules, as the two drugs compete for the same elimination pathway, potentially increasing serum concentrations of adefovir or the coadministered drug.
[Pharmacological Action]
Mechanism of Action: Adefovir is an acyclic nucleoside analog of adenosine monophosphate. It is phosphorylated by cellular kinases to its active metabolite, adefovir diphosphate. Adefovir diphosphate inhibits HBV-DNA polymerase (reverse transcriptase) through two mechanisms: competition with the natural substrate deoxyadenosine triphosphate and termination of DNA chain elongation following integration into viral DNA. The inhibition constant (Ki) of adefovir diphosphate against HBV-DNA polymerase is 0.1 μM, but its inhibitory activity against human DNA polymerases alpha and gamma is weaker, with Ki values of 1.18 μM and 0.97 μM, respectively.
Storage: Sealed
Strength: 10 mg
Packaging: 10 mg x 14 tablets/bottle
Expiry Life: Tentatively 24 months.
Approval Number: National Medicine Standard H20080034
Manufacturer: Chenxin Pharmaceutical Co., Ltd.
