The blocking drug for HIV is actually recommended to be applied within 24 hours, the sooner it is applied the better, with the best effect within 2 hours. If the time is longer, reaching close to 72 hours, it can also be used, but the corresponding blocking effect is likely to be reduced. It can be divided into basic and intensive regimens. The basic regimen is a combination of two nucleoside reverse transcriptase inhibitors, either tenofovir combined with emtricitabine, or tenofovir combined with lamivudine. If the renal function is not so good, then instead of tenofovir, you can choose lamivudine combined with zidovudine, which is the basic regimen. Intensive regimen is the combination of another type of action on the basic regimen, you can choose integrase inhibitors, such as raltegravir or dolutegravir, but many places this drug can not buy, so you can also choose non-nucleoside reverse transcriptase inhibitors, such as efavirenz, or combined with protease inhibitors, such as lopinavir ritonavir, are required to take 28 days of time, without interruption.