In the treatment of chronic hepatitis B, antiviral therapy is fundamental. There are two major classes of anti-hepatitis B viral drugs, namely interferons and nucleoside (acid) analogues. Nucleoside analogs are generally welcomed by doctors and patients because of their convenience of oral administration and low side effects. At present, the nucleoside drugs listed in China include lamivudine, adefovir, telbivudine and entecavir, etc. Tenofovir is a new drug that will enter our market soon. In the face of numerous nucleoside drugs, which one should be selected is sometimes difficult, but there are several aspects that can be controlled. 1, look at the viral load Before antiviral treatment doctors will test the patient’s blood for viral content (i.e. HBV DNA), if the viral content is high (more than 105copies/ml or more), you should choose strong antiviral drugs such as lamivudine, telbivudine and entecavir. Adefovir is weak and should not be used alone, unless combined with the above three drugs. 2, look at the e antigen content The common phrase “major triple-positive” refers to patients who are e antigen positive and e antibody negative. One of the goals of antiviral treatment for these patients is to make the e antigen turn negative and the e antibody turn positive, that is, the so-called “big three” turn into “small three”. For patients with high e antigen content, you can consider the option of tibivudine, which has the highest rate of e antigen conversion among all nucleoside analogs. 3, look at fertility needs For young couples with fertility requirements can choose pregnancy B drugs, i.e., telbivudine or lamivudine. Over the years, a large number of clinical applications have not found that these two drugs have adverse effects on the fetus, so they can be considered for use in the case of weighing the pros and cons. Of course, it may be safer to use them after the third month of pregnancy. Adefovir and entecavir have fetal teratogenic effects and should not be used in pregnant women or couples with short-term fertility requirements. 4, look at the side effects Nucleoside drugs generally have no obvious toxic side effects, most patients can accept the regular dose of treatment, but in individual cases need to be used with caution. Patients with renal insufficiency should not use adefovir, because adefovir has an effect on renal function, and other drugs should also be adjusted in dose according to renal function status. Tebivudine should not be used in patients with myopathy or peripheral neuritis. When there is lactic acidosis, the application of various nucleoside drugs should be cautious. Because the course of nucleoside drugs is more than 3 years, the cost is relatively high, and the drugs cannot be stopped at will in the middle of the course, so when you start to choose the drugs, in addition to the efficacy and side effects, the economic conditions of the family and whether the drug costs are included in the medical insurance reimbursement must also be considered. Among the four drugs, the price of entecavir is the highest, followed by tipifudin and adefovir is the lowest. The price of imported drugs is higher than that of domestic drugs in the same category. There is a reason why it is expensive, and there is a reason why it is cheap, so pay attention to full communication with your doctor when choosing a drug. The long-term application of nucleoside analogs can produce viral mutations and make the drug lose its antiviral activity. The highest rate of drug resistance is lamivudine, followed by tibivudine, with a lower rate of resistance to adefovir and entecavir. If lamivudine or telbivudine resistance occurs, adefovir combination therapy can be added or replaced with entecavir monotherapy or entecavir plus adefovir combination therapy; if adefovir resistance occurs, any one of the other three nucleoside analogues can be added; if entecavir resistance occurs, adefovir combination therapy can be added. If tenofovir becomes available in the future, all the four nucleoside analogues mentioned above can be replaced with tenofovir treatment. 7, other precautions Once you receive nucleoside drug treatment, you should adhere to the daily medication, not three days to fish and two days to sunbathe, and not arbitrarily replace the drug, otherwise it is easy to produce drug resistance. The treatment should not be terminated at will, especially for patients with hepatitis B cirrhosis, otherwise it may lead to recurrence of hepatitis, and in severe cases, life-threatening fulminant hepatitis may occur. It is important to review regularly to evaluate the efficacy and side effects. A comprehensive efficacy evaluation should be conducted during the first six months of initial treatment, and if the results are unsatisfactory or significant side effects occur, the treatment should be adjusted under the guidance of a specialist.