Treating HIV with drugs is called antiretroviral therapy or ART. ART can be confusing because 3-5 different drugs are often prescribed to be taken simultaneously. There are 5 different kinds of medications that can be prescribed to manage HIV in total. The reason for this is that different types of HIV drugs stop the virus from replicating at different stages in the RNA replication process. This makes the treatment more effective by preventing more copies of the virus from being created in the body’s immune cells. There are also some other drugs that help make the antiretroviral drugs more effective.
Here are the 5-6 different types of drugs used to treat HIV depending on how they are broken down into categories. They are listed in the order that they interfere with the viral replication process:
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Fusion Inhibitors & Entry Inhibitors: Fusion inhibitors and entry inhibitors prevent the virus from entering a healthy cell in the first place. They block the virus from merging with CD4 cell membranes. There are different types of drugs within this category that work to prevent the virus from entering healthy cells in different ways. Some drugs bind to proteins on the surface of CD4 cells or HIV and others bind with CCR5 receptors or CXCR4 receptors on the surface of the cells. One entry inhibitor drug is Fuzeon.
Protease Inhibitors: Protease inhibitors work by blocking an enzyme used by HIV, the protease enzyme. The protease enzyme is required to break up larger proteins into small pieces which the virus does before replicating itself. This occurs once the virus has already entered a cell. Some protease inhibitor drugs also serve another purpose: they are booster drugs. They help other HIV medications to be more effective by blocking liver enzymes that quickly metabolize some antiretroviral medications. An example of these types of drugs include Norvir and Tybost.
Nucleotide Reverse Transcriptase Inhibitors (NRTIs): These medications work by blocking reverse transcriptase, an enzyme used by the virus to replicate itself once inside a cell. Specifically, this enzyme modifies the genetic material of the virus so that it can be incorporated with the host’s DNA. NRTIs insert themselves into the HIV DNA chain and act as fake building blocks. This stops the completion of the new HIV DNA chain. An example of this type of drug is abacavir.
Non-nucleotide Reverse Transcriptase Inhibitors (NNRTIs): These medications are similar and stop the virus at the same stage in the replication process as NRTIs, but they don’t act as fake building blocks and they bind to a different site. They stop the chemical reaction of DNA polymerization. An example of this type of drug is Sustiva.
Integrase Inhibitors: Integrase inhibitors block the enzyme known as integrase. This enzyme is essential for the viral DNA to incorporate itself with the host’s DNA. Once this DNA integration occurs, the cell becomes a permanent carrier of the virus. An example of this type of drug is Isentress.
Choosing the Right Combination of Medications
Choosing what combination of the above medications is best is up to the patient and physician. The right ART will depend on how advanced the virus is, how resistant the particular strain is, and also any other health conditions the patient might have. Another factor to consider is how well a patient handles side effects. Some people may experience little to no side effects for one drug while another person may have extreme nausea and fatigue from the same drug. Some individuals also prefer to take fewer pills even though they cost more, so they opt for combination drugs that are more convenient. Think about what factors are most important for you when discussing ART therapy with your doctor. For more information about HIV medications, visit our HIV/AIDS Condition Page.
