The instructions for entecavir do not place strict limits on when it can be taken, and it is possible to change the time of day as long as the dosage is taken in accordance with the regimen. Entecavir needs to be broken down by stomach acid, and the instructions require that it be taken on an empty stomach, so after changing the time of day, it should also meet the conditions of an empty stomach, for example, it can be taken on an empty stomach at bedtime. Entecavir is a drug for the treatment of adult hepatitis B. Entecavir is essentially a guanine nucleoside analog, which inhibits the polymerase enzyme in the hepatitis B virus and thus achieves antiviral effects. According to the product specification, there is no strict limitation on the time of taking entecavir, but the dosage of entecavir for different groups of people is not necessarily explained in the specification, for example, adults and young people over 16 years of age should be taken once a day according to the dosage, and the dosage of entecavir should be adjusted according to the actual creatinine clearance rate of the patients with renal insufficiency. However, the drug is contraindicated in people who are allergic to entecavir or any of the components of the preparation, and in people who experience intolerance to adverse reactions after taking the drug, such as headache, fatigue, dizziness, nausea and other common adverse reactions. At the same time, if any new symptoms and co-medication occur during the course of taking the drug, you should promptly inform your doctor to change the medication under the doctor’s guidance to avoid certain adverse effects on your health.