All antiretroviral medications fight HIV, but the different classes work in different ways. Integrase inhibitors, also called INSTIs, block the action of an enzyme, HIV integrase, which the virus needs in order to multiply.
A healthcare provider may prescribe integrase inhibitors along with other antiretroviral medications to keep HIV under control. This treatment approach can be called antiretroviral therapy, highly active antiretroviral therapy, or combination antiretroviral therapy.
In this article, we take a close look at integrase inhibitors, including their actions, side effects, and brand names.
How do integrase inhibitors work?
A doctor may prescribe integrase inhibitors in combination with other medication to treat HIV.
When a person contracts HIV, the virus targets certain cells in the immune system, called cluster of differentiation 4 (CD4) cells. These are important because they direct other immune system cells to fight infections and illnesses.
HIV cells insert their own genetic information into the DNA of CD4 cells, which stops CD4 cells from working properly. Over time, HIV can cause the number of CD4 cells to decline, leaving the body less able to fight off infections and other illnesses.
To get inside CD4 cells and replicate, HIV needs an enzyme called integrase. Without this enzyme, the virus cannot make copies of itself.
Integrase inhibitors stop integrase from working, which stops HIV from entering CD4 cells.
These medications do not cure HIV, but they keep the virus from multiplying. As part of an antiretroviral treatment plan, they help reduce the amount of HIV in the body to undetectable levels.
When levels are undetectable, a person cannot transmit the virus to others, and with effective treatment, a person with HIV can experience the same quality of life as a person without the virus.
Integrase inhibitor drug names
There are several types of integrase inhibitor, and each blocks integrase differently.
A healthcare professional will choose an integrase inhibitor based on a person's health history and whether they have tried other medications. A person takes integrase inhibitors with other HIV medicines.
The United States Food and Drug Administration (FDA) have approved the following integrase inhibitors for use:
- bictegravir, which is only available in combination with emtricitabine and tenofovir alafenamide, under the brand name Biktarvy
- dolutegravir, which is sold under the brand name Tivicay
- elvitegravir, which is sold under the brand name Vitekta.
- raltegravir, which is sold under the brand name Isentress.
A person must take elvitegravir with another type of HIV medication called a protease inhibitor, as well as with a medicine called ritonavir, which appears under the brand name Norvir.
Integrase inhibitors are available in many combination antiretroviral medications. Often, a person takes all of their HIV medications in a single daily pill.
Side effects of integrase inhibitors
Headaches are a potential side effect of integrase inhibitors.
Newer HIV drugs, including integrase inhibitors, tend to cause fewer or milder side effects than older medications.
Most side effects of integrase inhibitors are manageable, but individuals react differently, and these side effects can be severe in some people. Often, the side effects last for only a few days, but they may last longer or not go away.
Overall, the benefits of treating HIV outweigh the risks. With so many treatment options available, it is often possible to work with a healthcare provider and find a combination of medications that do not cause bothersome reactions.
To manage integrase inhibitor side effects, it is important to communicate with a healthcare provider regularly. This includes:
- discussing the possible side effects of antiretroviral drugs before starting treatment
- learning the best ways to manage side effects if they arise and become bothersome
- knowing which side effects can be severe and require emergency medical care
- notifying a healthcare provider right away if side effects develop
- talking about alternative medications
It is important to keep taking all antiretroviral medicines, including integrase inhibitors, as prescribed. A person should never stop or change a dosage unless they are advised to by a healthcare provider.
Following the treatment plan stops the virus from multiplying and damaging the immune system. Not following it may cause the virus to become resistant to the drug. If this happens, medications may be less effective.
Some of the most common side effects of integrase inhibitors include:
- mood changes
- abnormal dreams
- muscle pain
- a rash
In rare cases, a person may experience swelling of the face, eyes, lips, tongue, or throat. This is serious and requires emergency medical care. Call for medical assistance or go to the nearest emergency room if this happens.
Integrase inhibitors can cause dangerous interactions with other drugs, herbs, and supplements.
Before starting antiretroviral treatment, a person should tell their healthcare provider about every medication they are taking, prescription or otherwise. Also, mention any herbs, vitamins, or supplements.
Measuring treatment success
A blood test will help determine whether the integrase inhibitors are working.
A key aspect of treatment involves monitoring how well a person is responding. Doctors use two blood tests to measure HIV treatment success:
- CD4 cell count
- HIV viral load
The CD4 cell count shows how many CD4 cells are present in a blood sample. A person with HIV may take this test at the beginning of treatment and then every few weeks or months.
A higher CD4 cell count means that the immune system is functioning well. Doctors usually consider a count of 500–1,200 CD4 cells per cubic millimeter of blood to be the normal range. The CD4 count tends to rise during treatment, and this shows that the virus is under control.
The viral load count shows how much of the virus' RNA is in the blood. The goal is to lower this amount to undetectable levels.
Once this occurs, it means that HIV is not progressing and that there is no chance of transmitting it. However, even after the viral load drops to undetectable levels, it is still crucial to take medications every day as prescribed.
Avoiding drug resistance
In some cases, HIV can become resistant to integrase inhibitors, especially if a person does not follow the treatment plan.
To help avoid drug resistance, follow the healthcare provider's instructions about when and how to take HIV medications every day.
If a person has side effects or any other issues that make taking medications difficult, talk to the healthcare provider right away. They can help come up with alternatives. Never stop treatment, skip doses, or take more or less medication unless a healthcare provider has recommended it.
Integrase inhibitors, or INSTIs, are a class of antiretroviral medication that doctors use to treat HIV.
Integrase inhibitors block the action of a specific enzyme, HIV integrase, which prevents the virus from multiplying in the blood.
There are several types of integrase inhibitors, and some common brand names include Biktarvy, Tivicay, Vitekta, and Isentress.
Researchers have developed a variety of advanced antiretroviral drugs in recent years, and a person will likely be able to find a combination of medications that fits their needs and lifestyle.
Often, a person can take all of their daily antiretroviral medications in a single pill.
With effective treatment and a suppressed viral load, a person with HIV can enjoy the same quality of life as a person without the virus.