Lamivudine Tablets

Pharmacological action: Lamivudine is a nucleoside analog that can be phosphorylated in cells to become lamivudine triphosphate (L-TP), and is embedded into viral DNA in the form of cyclic adenosine phosphate by hepatitis B virus (HBV) polymerase, resulting in the termination of DNA chain synthesis. Lamivudine triphosphate is a weak inhibitor of mammalian (, (, and (-DNA polymerases. In in vitro experiments, the half-life of lamivudine triphosphate in hepatocytes is 17-19 hours. Lamivudine is an antiviral drug that has shown inhibitory effects on hepatitis B virus in a variety of experimental cell lines and infected animal models. However, in two of the animal models (ducklings and chimpanzees), the serum DNA levels of hepatitis B virus rebounded within 4 and 14 days, respectively, after stopping treatment with this drug. Long-term use of lamivudine can lead to a decrease in the sensitivity of HBV to it. Genotype analysis of the virus strains showed that this change was related to HBV polymerase. The mutation is related to the substitution of valine or isoleucine for methionine at position 552 of the YMDD sequence in the catalytic reaction region of the synthase, and the substitution of methionine for leucine at position 528. In vitro, the replication ability of HBV recombinants containing the YMDD mutation is lower than that of wild-type HBV. It is not clear whether other mutations of HBV are related to its decreased sensitivity to lamivudine in vitro. Toxicological studies: Genetic toxicity: Lamivudine did not show mutagenic activity in microbial mutagenicity tests and in vitro cell transformation experiments, but showed weak mutagenic activity in in vitro cultured human lymphocytes and mouse lymphoma experiments. Rats were orally administered lamivudine for 200 0mg/kg (the blood concentration is 60-70 times the recommended clinical dose for patients with chronic hepatitis B), no obvious genetic toxicity was observed. Reproductive toxicity: Rats were orally administered lamivudine 4000mg/kg/day (the blood concentration is 80-120 times the clinical blood concentration of humans), and their fertility and the survival, growth, and development of the offspring after weaning were not significantly affected. Rats and rabbits were orally administered lamivudine 4000 and 1000mg/kg/day (the blood concentration is about 60 times the blood concentration of the clinically recommended dose for humans), respectively, and no obvious teratogenic effects were shown. When the blood concentration of rabbits was close to the blood concentration of the clinically recommended dose for humans, the teratogenic effect was not significantly affected. When the concentration of lamivudine is similar to that of lamivudine in the blood, an increase in early embryonic mortality occurs. However, when the blood concentration of the drug in rats reaches 60 times the blood concentration of the recommended clinical dose in humans, no such phenomenon occurs. The results of studies on pregnant rats and rabbits show that lamivudine can cross the placenta and enter the fetus. There is no adequate and strictly controlled clinical research data on the use of lamivudine in pregnant women. The concentration of lamivudine in the milk of lactating rats is similar to that in plasma. Carcinogenicity: The results of long-term carcinogenicity tests on rats and mice show that when the exposure level reaches 34 times (mice) and 200 times (rats) of the human clinical exposure level, no obvious carcinogenicity is shown.

Lamivudine

Film-coated tablets appear white after removing the film coating.

It is indicated for the treatment of adult patients with chronic hepatitis B with elevated alanine aminotransferase [ALT], viral activity and replication, and compensated liver function.

Oral administration: adults 0.1g at a time, once a day.

Common adverse reactions include upper respiratory tract infection-like symptoms, headache, nausea, malaise, abdominal pain and diarrhea. The symptoms are generally mild and can be relieved on their own.

1. Patients who are allergic to this product are prohibited from using it; 2. Patients within 3 months of pregnancy should not use this product, pregnant women and lactating women should use it with caution.

Precautions for children: There is no data on the use of lamivudine in children in China. Precautions for pregnancy and lactation: Patients within 3 months of pregnancy should not use this product, and pregnant and lactating women should use it with caution. Precautions for the elderly: For elderly patients whose renal excretion function decreases due to aging, there is no significant change in lamivudine metabolism, and it will only be affected when the creatinine clearance rate is <30ml/min.

Since the drug metabolism and plasma protein binding rate of this product is low, and it is mainly cleared by the kidneys as the original drug, the incidence of potential interactions with other drug metabolites is very low. Lamivudine is mainly cleared in the form of active organic cations. When used simultaneously with drugs with the same excretion mechanism, especially when the main clearance route of the drug is active renal secretion through the organic cation transport system (such as trimethoprim), the interaction should be considered. Studies have shown that some other drugs that are cleared by this mechanism (such as ranitidine and cimetidine) have no interaction with lamivudine. Drugs that are mainly excreted in the form of active organic anions or through glomerular filtration will not have clinically significant interactions with lamivudine. When lamivudine is taken simultaneously with trimethoprim (160 mg)/sulfamethoxazole (800 mg), the exposure of lamivudine can be increased by 40%. However, lamivudine does not affect the pharmacokinetic properties of trimethoprim/sulfamethoxazole. Therefore, unless the patient has renal impairment, there is no need to adjust the dosage of lamivudine. When lamivudine and zidovudine are taken simultaneously, a moderate increase in the Cmax of zidovudine, about 28%, can be observed, but there is no significant change in the systemic bioavailability (area under the concentration-time curve AUC). Zidovudine does not affect the pharmacokinetic properties of lamivudine (see Pharmacokinetics). There is no pharmacokinetic interaction between lamivudine and (-interferon when used simultaneously; no clinical observation has been made of lamivudine and commonly used immunosuppressants.

Protect from light, seal and dry in a cool place.

0.1g

24 months

Hunan Qianjin Xiangjiang Pharmaceutical Co., Ltd.

• Founded in:

  1998-05-26

• Address:

  No. 1, Jinlong East Road, Hetang District, Zhuzhou City, Hunan Province

• Tax NO.:

  9143020071210238X7

• Registered Funds:

  48 million yuan

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