Acquired immunodeficiency syndrome (AIDS)
AIDS is a disease of the immune system. It is caused by the human immunodeficiency virus (HIV). AIDS can be diagnosed by:
- A decline to less than 200 CD4 cells per millimeter cubed (cells/mm3) of blood
- The occurrence of an opportunistic infection (OI)
Adherence means following a prescribed course of treatment. It means taking the correct dose of a medicine. And it means taking the medicine at the right time.
AIDS Service Organization (ASO)
An ASO is a group that provides community-based support and services for people living with HIV and AIDS. Many ASOs also provide support services for families and friends. Working to prevent HIV is often among the type of work ASOs do. An ASO can be a health association, a support agency, or other service group.
An antiretroviral drug is a medicine that blocks a retrovirus from making copies of itself (multiplying). HIV is a type of retrovirus.
Antiretroviral therapy (ARV)
ARV therapy refers to medicines that block HIV from making copies of itself (multiplying). This can help slow the progress of HIV infection. Usually, 3 or more different HIV medicines from 2 or more HIV drug classes are combined in a regimen.
CD4 cells are also called T cells or T helper cells. They are a type of white blood cell that fights infection.
A CD4 count is the number of CD4 cells in a small sample of blood. Normally, there are between 500 and 1800 CD4 cells per millimeter cubed (cells/mm3) of blood. HIV destroys CD4 cells and can cause the CD4 count to go down.
A dose is the amount of a prescribed medicine that is taken at a time.
A drug class is a group of medicines that share common features, such as mode of action (how they work). The 6 classes of HIV drugs are nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), entry inhibitors, fusion inhibitors, and integrase strand transfer inhibitors (INSTIs, or integrase inhibitors).
When one medicine alters the activity of another medicine, it is called a drug interaction. A drug interaction might change how the medicine works by changing the drug’s activity. Side effects may be worse, or new side effects may occur. The medicines may be handled in unexpected ways by the body. Food and herbal medicines may also affect the activity of drugs.
Entry inhibitors (CCR5 blockers)
Entry Inhibitors are a class of drugs that are used in combination therapy to treat HIV. They work by blocking HIV entry into CD4 cells.
Food and Drug Administration (FDA)
The FDA is a government group whose job is to protect the public health. The FDA ensures that medicines are safe and effective.
Fusion inhibitors are a class of drugs that are used in combination therapy to treat HIV. They work by blocking HIV entry into CD4 cells.
HAART (highly active antiretroviral therapy)
When several HIV medicines from different drug classes are taken in combination, it is called highly active antiretroviral therapy, or HAART. Usually, 3 or more different HIV medicines from 2 or more different drug classes are combined in a regimen.
HIV stands for human immunodeficiency virus. It is the virus that causes AIDS.
The immune system is the body's defense system. It fights infections and other diseases. Certain cells of the immune system (CD4 cells) are attacked and destroyed by HIV.
Integrase strand transfer inhibitors (INSTIs)
INSTIs, or integrase inhibitors, are a class of drugs that are used in combination therapy to treat HIV. They work by blocking the action of integrase. Integrase is a protein that HIV uses to insert its genetic material into the genetic material of CD4 cells as the virus makes copies of itself.
Lipodystrophy, also called fat redistribution or body shape changes, refers to a change in the way your body produces, uses, and stores fat. It can refer either to the buildup of fat or the loss of fat in certain areas of the body.
The term meds is sometimes used instead of the words medications, medicines, and drugs that are used to treat disease.
In HIV, the word mutation refers to a change in the virus that can occur when the virus makes incorrect copies of itself. This change may cause certain HIV medicines to stop being effective against the virus.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
NNRTIs (non-nukes) are a class of drugs that are used in combination therapy to treat HIV. They bind to and disable a protein that HIV needs to make copies of itself. That protein is called reverse transcriptase.
Nucleoside reverse transcriptase inhibitors (NRTIs)
NRTIs (nukes) are a class of drugs that are used in combination therapy to treat HIV. They act like fake building blocks that HIV needs to make copies of itself. When HIV uses an NRTI instead of a normal building block, the copying process is disrupted.
Opportunistic infections (OIs)
An OI is an illness that occurs in people who have weak immune systems, such as people with HIV or AIDS. A weak immune system is not able to protect and defend the body from some infections.
Prescription medicines come with a written paper with facts about the medicine called Prescribing Information. It describes how to use the medicine, what dose to take, what harmful effects could occur from taking it, and other important facts. The US Food and Drug Administration (FDA) approves the prescribing information for all prescription medicines.
Protease inhibitors (PIs)
PIs are a class of drugs that are used in combination therapy to treat HIV. They disable a protein that HIV needs to make copies of itself. That protein is called protease.
In HIV, a regimen refers to the combination of medicines used to treat HIV infection.
Replication is the process by which something makes a copy of itself. In HIV, replication is the process by which the virus multiplies.
HIV can change after exposure to a medicine. This change is called a mutation. When HIV mutates, certain HIV medicines may no longer be able prevent the virus from making copies of itself. The virus is then said to have developed resistance to those medications.
Reverse transcriptase is a type of protein found in HIV. It is needed for HIV to make copies of itself. Some medicines used to treat HIV interfere with this protein.
Side effects is a term that usually refers to negative or adverse reactions to a medicine.
Transmission refers to the spread of HIV from one person to another.
Undetectable refers to an HIV viral load that is so low that it cannot be measured by current HIV tests. It does not mean that HIV is gone from the body.
Viral load is a measure of the amount of HIV in a sample of blood. Healthcare providers use viral load to monitor their patients' HIV and how well the patients’ HIV medicines are working.