Tenofovir disoproxil fumarate tablets taken 4 tablets at a time may cause drug poisoning. Tenofovir disoproxil fumarate tablets is an antiviral drug that is mainly used to treat HIV-1 infection, but can also be used to treat chronic hepatitis B in children and adult patients over 12 years of age. The usual dosage of the drug is 1 tablet at a time, and when 4 tablets are taken at a time, it is a case of drug overdose. Patients must be monitored closely for signs of drug toxicity, such as lethargy, nausea, vomiting, delirium, convulsions, and lactic acidosis. If there are symptoms of toxicity, hemodialysis is performed to effectively remove tenofovir from the body. The drug may have adverse reactions such as diarrhea, nausea, hypophosphatemia, decreased serum phosphates, and is contraindicated in patients who are allergic to the drug. The medication must be used in strict accordance with the doctor’s instructions, do not increase the dosage without authorization, and notify the doctor in time to deal with any uncomfortable symptoms.