Tenofovir disoproxil fumarate is tenofovir disoproxil fumarate. Tenofovir disoproxil fumarate can be replaced by entecavir, but it is not recommended to change the drug frequently. Tenofovir disoproxil fumarate and entecavir belong to the first-line hepatitis B antiviral drugs, and they can replace each other. In case of poor efficacy or adverse effects of tenofovir disoproxil fumarate, as well as for cost considerations, patients who want to replace the drug can do so under the guidance of a professional doctor, and it is recommended to closely monitor the liver and kidney functions as well as the hepatitis B viral load during the period of replacing the drug. Although entecavir can replace tenofovir disoproxil fumarate, it is not recommended to change the antiviral drug frequently, which not only affects the efficacy of the drug, but also aggravates the burden on the liver and kidneys, as well as increases the chance of adverse reactions. If patients need antiviral drugs, they should use them under the guidance of a professional doctor, and should not use them on their own to avoid delaying their condition.