HIV generally refers to the HIV virus. Blocking drugs for AIDS can inhibit viral synthesis and have a good blocking effect. Blocking drugs such as lamivudine are generally taken within 3 days of being injected with HIV blood and can do a good job of blocking the virus. HIV is mostly an RNA virus, which needs to synthesize DNA through reverse transcription, and then further replicate and transcribe. HIV blocking drugs such as lamivudine generally inhibit viral synthesis by inhibiting the enzyme nucleotide reverse transcriptase, which has a good blocking effect. After being injected with HIV blood, the sooner you take the blocking medication, the better the blocking effect will be, generally within 72 hours have some effect, the best within 2 hours to ensure that the virus can take effect before entering the bloodstream. If you have been injected with HIV blood, you should consult a doctor in time, take the blocking medication on time under the guidance of a professional doctor, and have regular checkups to improve the success rate of blocking.