Adherence
How closely you follow, or adhere to, your treatment regimen. This includes taking the correct dose at the correct time as prescribed by your healthcare provider. If you are not taking medications as prescribed, they may not work properly.
Acquired Immunodeficiency Syndrome (AIDS)
The most serious stage of HIV infection. HIV-infected patients are diagnosed with AIDS when their CD4 cell count falls below 200 or if they develop an AIDS-defining illness (an illness that is very unusual in someone who is not HIV positive).
AIDS Service Organization (ASO)
A health association, support agency or other service actively involved in the prevention and treatment of HIV/AIDS.
Antiretroviral
A medication that interferes with replication of retroviruses. HIV is a retrovirus.
CD4 Cells
A type of white blood cell that fights infections (also referred to as T cells or T-helper cells). When HIV enters a person's CD4 cells, it uses the cells to make copies of itself. This process destroys the CD4 cells, and the CD4 count goes down and the immune system becomes weak. A CD4 cell count is the number of CD4 cells in a sample of blood.
CD4 Cell Count
The number of CD4 cells in a sample of blood.
Combination HIV Therapy
Two or more HIV medications used together to achieve optimal results in controlling HIV infection.
Deoxyribonucleic Acid (DNA)
The molecular chain found in genes within the nucleus of each cell, which carries the genetic information that enables cells to reproduce. DNA is the main part of chromosomes, the structures that transmit hereditary characteristics.
Dose
The recommended amount of a drug to be taken.
Drug Class
Drugs with similar design and method of fighting HIV. There are four classes of HIV medications currently FDA approved: nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and fusion inhibitors (FIs). Each class of medications fights HIV in a different way. The primary difference between each class is the stage of HIV replication that the medications target.
Drug Interactions
A change in the effect of a drug when administered with another drug. The effect may be an increase or a decrease in the action, or it may be an adverse effect that is not normally associated with either drug.
Drug Resistance
As HIV replicates it can mutate (change form), which may result in HIV that cannot be controlled with certain medications. HIV is considered resistant to a medication when that medication is no longer effective against it.
Drug Resistance Test
A laboratory test to determine if an individual's HIV strain is resistant to any HIV medications.
Flare-up
When a disease suddenly intensifies or returns in a worse way than before.
Fusion
An important step in the process whereby HIV enters CD4 cells.
Fusion Inhibitor (FI)
A class of HIV medications that work by blocking an important step in the process of HIV entry into CD4 cells known as fusion. By blocking fusion, FIs may prevent HIV from infecting CD4 cells.
HAART (Highly Active Antiretroviral Therapy)
A combination of three or more different drugs from different classes, such as two nucleoside reverse transcriptase inhibitors (NRTIs) and a protease inhibitor (PI), two NRTIs and a non-nucleoside reverse transcriptase inhibitor (NNRTI) or other combinations. These treatment regimens have been shown to reduce the amount of virus so that it becomes undetectable in a patient's blood.
Hepatitis B Virus (HBV)
A virus that causes inflammation of the liver. HBV is typically transmitted through contact with contaminated blood during sexual contact or while sharing needles.
Hepatomegaly
Enlargement of the liver.
Hepatotoxicity
Toxicity of the liver.
Human Immunodeficiency Virus (HIV)
The virus that causes AIDS. If left untreated, HIV infection damages a person's immune system and can progress to AIDS.
Lactic Acidosis
A condition in which lactic acid accumulates in body tissues. The cells make lactic acid when they use glucose (sugar) for energy.
Lipodystrophy
A disturbance in the way the body produces, uses and distributes fat. In HIV disease, lipodystrophy has come to refer to a group of symptoms that seem to be related to the use of certain protease inhibitor (PI) and nucleoside reverse transcriptase inhibitor (NRTI) medications. These symptoms may include increased amount of fat in the upper back and neck ("buffalo hump"), breast and around the main part of your body (trunk). Loss of fat from the legs, arms and face may also happen. The cause and long-term health effects of these conditions are not known at this time.
Mutation
In HIV, a mutation refers to a changed form of the virus that occurs when HIV does not reproduce itself properly. This may result in HIV that is resistant to (cannot be controlled by) certain medications.
Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI)
A class of HIV medications that inhibit, or help to slow down, HIV multiplication by binding to the reverse transcriptase enzyme.
Nucleoside
A building block of nucleic acids, DNA or RNA, the genetic material found in living organisms.
Nucleoside Reverse Transcriptase Inhibitor (NRTI)
A class of HIV medications that share structural characteristics of naturally occurring nucleosides and inhibit, or help to slow down, HIV multiplication by interfering with the reverse transcriptase enzyme.
Opportunistic Infections
Illnesses caused by various organisms that occur in people with weakened immune systems, including people with HIV/AIDS. Opportunistic infections common in persons diagnosed with AIDS include
Pneumocystis carinii pneumonia; cryptosporidiosis; histoplasmosis; other parasitic, viral and fungal infections; and some types of cancers.
Prescribing Information
Also referred to as the package insert, product label or product information, this document is the primary reference for information about a prescription drug. The prescribing information is approved by the U.S. Food and Drug Administration.
Protease
An enzyme that breaks down proteins into their component peptides. HIV's protease enzyme cuts long chains of HIV into smaller, active proteins used in HIV replication.
Protease Inhibitor (PI)
A class of HIV medications that inhibit, or block, the HIV protease enzyme. Without HIV protease, the virus cannot make more copies of itself.
Replication
The process by which HIV makes a copy of itself, or reproduces.
Reverse Transcriptase
A substance in a cell called an enzyme that is responsible for translating RNA into DNA. In the case of HIV, RNA contains the "blueprint" for making more HIV; the RNA must be translated into DNA so that CD4 cells can produce new copies of HIV. Some HIV medications work by interfering with this stage of the HIV life cycle.
Ribonucleic Acid (RNA)
Most viruses and all bacteria, plants and animals have genetic codes made up of DNA, which uses RNA to build specific proteins. The genetic material of a retrovirus such as HIV is the RNA itself. HIV inserts its own RNA into the host cell's DNA, preventing the host cell from carrying out its natural functions and turning it into an HIV factory.
Side Effects
Reactions caused by a drug in a person's body other than what the drug was designed to do (for example, nausea from a drug that is taken to fight HIV).
Transmission
The process by which HIV is spread, or transmitted, from one person to another. HIV is spread most commonly by sexual contact with an infected partner. HIV also is spread through contact with infected blood, most often by the sharing of drug needles or syringes contaminated with minute quantities of blood containing the virus.
Treatment Experienced
Description for people who have already received medications for the treatment of HIV.
Treatment Failure
When a particular course of HIV therapy is no longer able to control HIV in a person's body. Treatment failure is usually determined by increases in viral load and reductions in CD4 cell counts.
Treatment NaÏve
Description for people who have never been treated with medications for HIV.
Treatment Regimen
Two or more HIV medications used together to achieve optimal results in controlling HIV infection.
Undetectable
When HIV is still present in the blood, but at such low levels that it cannot be detected using existing viral load tests.
Viral Load
The amount of HIV in a sample of blood. Viral load testing measures the amount of HIV in one milliliter of a person's blood.
Viral Load Test
Test that measures the amount of HIV in the blood. Results are expressed as the number of copies per milliliter of blood. Viral load is one of the tests used to determine when to initiate and/or change HIV therapy.
