How Does HIV Prevention Medication Work?

HIV prevention medication, also known as pre-exposure prophylaxis (PrEP), works by blocking the entry of HIV into the body's cells. It is used to prevent HIV infection in individuals who are at high risk of exposure to the virus. Here's how PrEP works:

Mechanism of Action:

PrEP typically involves taking a daily pill that contains a combination of two antiretroviral drugs: tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC). These drugs belong to a class of medications called nucleoside reverse transcriptase inhibitors (NRTIs).

1. Blocking Viral Entry:

When taken consistently, PrEP creates a high concentration of these antiretroviral drugs in the body, particularly in the rectum and genital tissues. If someone who is taking PrEP comes into contact with HIV during sex or injection drug use, the drugs work by interfering with the virus's ability to enter and infect immune cells.

2. Preventing Reverse Transcription:

After HIV enters a host cell, it needs to convert its RNA genome into DNA to replicate. TDF and FTC work by inhibiting the reverse transcriptase enzyme, which is essential for this process. By blocking reverse transcription, these drugs prevent the HIV virus from establishing an infection.

3. Maintaining Drug Levels:

To ensure effective protection, PrEP must be taken daily as prescribed. Consistent use is crucial because it maintains the necessary drug levels in the body to block HIV infection. Missing doses or taking PrEP inconsistently can reduce its effectiveness.

Efficacy:

When used correctly and consistently, PrEP is highly effective in preventing HIV transmission. Studies have shown that PrEP can reduce the risk of HIV infection by up to 99% in individuals who are at high risk. However, it is important to note that PrEP is not 100% effective, and it does not protect against other sexually transmitted infections (STIs).

It is essential for individuals considering PrEP to consult with a healthcare provider to assess their risk, discuss potential side effects, and receive appropriate guidance on how to use it effectively.