A human immunodeficiency virus (HIV) diagnosis is no longer the death sentence it once was. Thirty years ago, doctors had little more than comforting words to offer patients who had been diagnosed with the virus. And while there remains no cure for HIV or AIDS, remarkable advancements in treatments and clinical understanding of how the disease progresses are allowing doctors to help patients live longer, fuller lives.
How HIV medications work
Antiretroviral drugs do not cure HIV. Instead, they suppress the virus and slow its progression in the body. Medications sometimes suppress the virus to undetectable levels, but they do not eliminate the virus from the body. If an antiretroviral medication is successful, you may be able to add many healthy, productive years to your life. While you may still be infected and capable of transmitting the virus, you will be able to maintain a higher health quality for a longer period of time. If the medications are not effective, the virus will likely advance more quickly, and you reach the final stages of the infection in a shorter period.
The most commonly prescribed antiretroviral medications approved by the U.S. Food and Drug Administration (FDA) can be divided into four classes. They are:
Reverse transcriptase (RT) inhibitors
RT inhibitors interrupt the life cycle of an HIV-infected cell as it tries to replicate itself. There are two types of RT inhibitor.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs) prevent HIV from making copies of itself. Common NNRTIs include efavirenz (Sustiva), nevirapine (Viramune), and etravirine (Intelence), and delavirdine, DLV (Rescriptor).
Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) keep HIV-infected cells from making copies of themselves by interrupting the reconstruction of the disease’s DNA chain. The most common NRTI is abacavir (Ziagen). Other NRTIs include:
- zidovudine (Retrovir)
- didanosine (Videx and Videx EC)
- zalcitabine (Hivid)
- stavudine (Zerit and Zerit XR)
- lamivudine (Zeffix and Epivir)
- emtricitabine (Emtriva)
The most common combination NRTIs are emtricitabine, tenofovir (Truvada), and lamivudine.
Protease inhibitors (PIs)
Protease inhibitors (PIs) disable protease, a protein HIV needs to make copies of itself. The most common PIs include:
- saquinavir (Invirase, Fortovase)
- ritonavir (Norvir)
- indinavir (Crixivan)
- nelfinavir (Viracept)
- amprenavir (Agenerase)
- lopinavir (Kaletra, in combination with ritonavir)
- alazanavir (Reyataz)
- fosamprenavir (Lexiva, Telzir)
- tipranavir (Aptivus)
- darunavir (Prezista)
Entry or fusion inhibitors
Entry or fusion inhibitors block HIV from entering CD4+ T-cells. These inhibitors include maraviroc (Selzentry) and enfuvirtide (Fuzeon).
Integrase inhibitors disable integrase, a protein that HIV uses to infect CD4+ T-cells. The most common integrase inhibitor is raltegravir (Isentress).
Other integrase inhibitors include:
- dolutegravir (Tivicay)
- elvitegravir (Vitekta)
Multidrug combination therapy
HIV cells can mutate and become resistant to a single medication. To avoid this, many doctors will prescribe a combination of medicines. A combination of three or more antiretroviral drugs is called highly active antiretroviral therapy (HAART) and it’s quickly becoming the initial treatment prescribed by doctors for patients with HIV.
When HAART was first approved by the FDA in the late 1990s, HIV-related deaths in the United States were cut by almost half within three years.
Advances in medicine are also making adherence to HAART much easier by reducing the number of pills a person must take and reducing side effects. The most common HAART treatment consists of two NRTIs and one NNRTI or a protease inhibitor.
In 2012, the FDA approved Stribild, a combination drug that contains four different medications for treating HIV—the drug Truvada (which contains both emtricitabine and tenofovir) and two new drugs, elvitegravir (an integrase inhibitor) and cobicistat.
Stribild is one of the first complete regimen treatments for HIV—it’s a single pill, taken once daily, and it cannot be combined with other HIV medications. Together, these four medicines prevent HIV from replicating and lower the overall viral load in the blood.
In 2011, a similar drug, Complera, was introduced and made available for patients with HIV. This single, once-daily pill contains a combination of emtricitabine, rilpivirine, and tenofovir.
Though a promising advancement, not every patient with HIV is qualified to take these combination pills. Talk with your doctor to see if you are, or find out how you can become qualified.
Drugs on the horizon
Each year, new therapies are gaining more and more ground as the future for treating and possibly curing HIV/AIDS. A drug class known as maturation inhibitors may potentially prevent HIV from maturing and properly developing. If these drugs work as designed, they could block HIV from merging with healthy cells.