Last update: January 2010
Selzentry™ – brand name
Celsentri - brand name used outside the US
maraviroc – generic name
Selzentry is a CCR5 antagonist. It belongs to a class of HIV drugs called entry inhibitors.
HIV infects white blood cells called CD4 cells and uses them to make more copies of itself. In order to do this, the virus must first enter the CD4 cell. To enter the cell, HIV attaches itself to receptors on the outside (surface) of the CD4 cell.
Each CD4 cell has a CD4 receptor and two co-receptors called CCR5 and CXCR4 on its surface. To enter the CD4 cell, HIV must attach to the CD4 receptor and either the CCR5 or the CXCR4 co-receptor.
Think of receptors as “keys.” HIV attaches to the CD4 “key” and also to either the CCR5 “key” or the CXCR4 “key” to “unlock” the cell.
- Virus that enters the CD4 cell using CCR5 co-receptors is called “CCR5 tropic” or “R5 virus”
- Virus that enters the CD4 cell using CXCR4 co-receptors is called “CXCR4 tropic” or “X4 virus”
- Virus that enters the CD4 cell using either CCR5 or CXCR4 co-receptors is called “R5X4” or “dual-tropic virus”
CCR5 antagonists work against HIV by attaching to the CCR5 co-receptor on the CD4 cell’s surface. This blocks HIV from attaching to the CCR5 co-receptor of that CD4 cell. If HIV cannot attach to the CD4 cell, it cannot enter and infect the cell. CCR5 antagonists work best for people whose HIV is CCR5 tropic.
The Food and Drug Administration (FDA) has approved Selzentry for use in
combination with other HIV drugs in HIV+ adult and adolescent patients who are
at least 16 years of age and have CCR5-tropic HIV.
Your health care provider needs to perform a blood test (called a tropism assay) to determine whether your HIV is CCR5 tropic.
Selzentry comes in 150 milligram (mg) and 300 mg tablets.
The recommended dose depends on what other drugs are combined with Selzentry:
Dose of Selzentry
150 mg twice a day
300 mg twice a day
600 mg twice a day
Selzentry can be taken with or without food.
Selzentry must be used in combination with other HIV medications to treat HIV.
It is important to take your HIV medicines as prescribed and at the same time each day. If you forget to take Selzentry, take it as soon as possible and then take your next scheduled dose at its regular time. If it is less than six hours before your next dose, do not take the missed dose. Wait and take the next dose at the regular time. Do not take a double dose to make up for a missed dose.
As with all HIV drugs, Selzentry should be taken as prescribed by your health care provider. Missing or skipping doses can cause your blood levels of Selzentry to fall too low and the virus can become resistant to it. This may cause Selzentry and other HIV drugs you are taking to stop working.
Selzentry is approved for people who are taking HIV drugs for the first time.
Selzentry is also approved for people who have HIV that is resistant to other drugs. Because Selzentry attacks HIV differently than most of the HIV drugs available right now, many HIV+ people with drug-resistant HIV will likely benefit from Selzentry.
Selzentry works best when combined with at least two other drugs that work well against your HIV. For this reason, you and your health care provider should use resistance testing and your treatment history to help guide the use of Selzentry and to determine which drugs will work best for you.
Your health care provider also needs to do a tropism test to determine whether your HIV is CCR5 tropic. If it is not, Selzentry should not be used.
If your virus develops resistance to Selzentry, the drug may stop working or may not work as well for you.
Sometimes taking more than one medication can cause drug interactions. This can lead to the drugs not working as well or an increased risk of side effects.
Selzentry can interact with other medications. The dose of Selzentry may have to be adjusted depending on what other medications you are taking (see table above under “How should I take Selzentry”). You should not take Selzentry with products containing the herb St. John’s Wort.
Because there are many possible drug interactions with Selzentry, it is very
important to go over all your medications with your health care provider. Be
sure your health care provider knows about all the medications you are taking
(including over-the-counter, prescriptions, street drugs, and herbs), even if
you only use them occasionally.
For more information and additional resources to check interactions between the particular drugs you are taking, see our info sheet on drug interactions or go to
It is not unusual to experience Selzentry side effects. However, they may be temporary and may go away as your body gets used to the medication. If you experience any of the side effects listed below, call your health care provider for advice. Do not just stop taking your medication.
- Swelling (fluid build-up)
- Sleep problems
- Urinary problems
- Cold-like symptoms
- Muscle pain
- Stomach pain
More serious side effects (may or may not be related to Selzentry):
- Liver toxicity: this may be associated with higher levels of blood cells
called eosinophils and higher levels of antibodies called immunoglobulins. An
allergic reaction may happen before liver problems occur. Stop taking Selzentry
and call your health care provider right away if you get any of the following
- An itchy rash on your body (allergic reaction)
- Your skin or eyes look yellow and/or dark (tea-colored) urine
- Vomiting and/or upper right stomach area (abdominal) pain
- Heart problems, including heart attack: Selzentry should be used with caution in people at increased risk for heart problems
- A drop in blood pressure when standing up that can cause dizziness or fainting
- Because Selzentry affects immune system cells, there is a potential risk of developing infections and cancers; however, this has not been seen in clinical trials
If you are experiencing persistent, unusual, or serious side effects, call your health care provider right away.
In the clinical trials conducted for approval of Selzentry, only 10.7% (68 patients) were women. Therefore, very little is known about whether Selzentry might act differently in women than it does in men.
Studies have shown that HIV+ pregnant women who use HIV drugs can greatly reduce the risk of passing HIV on to their babies. There have been no formal studies on the use of Selzentry during pregnancy.
An Antiretroviral Pregnancy Registry has been established to collect information on pregnant women who take HIV drugs, including Selzentry. If you are pregnant and taking Selzentry or other HIV drugs, your health care provider can register you by calling 1-800-258-4263 or going to www.apregistry.com.
It is not known whether Selzentry passes into breast milk. HIV+ women should not breast-feed because their babies could be infected with HIV through the breast milk.
Check with your health care provider about the best treatment options for you and your baby if you are thinking of getting pregnant.
Click this link for more information about pregnancy.
People who are starting HIV treatment for the first time may develop Immune Reconstitution Inflammatory Syndrome or IRIS. IRIS can happen as a result of the immune system getting stronger and responding to an HIV-related infection such as Mycobacterium avium infection (MAC), cytomegalovirus (CMV), Pneumocystis jirovecii pneumonia (PJP), or tuberculosis (TB). People may have been treated for these infections in the past or may not even know they have them. If you notice any unusual symptoms soon after starting HIV drugs for the first time, let your health care provider know right away so you can be evaluated and treated, if necessary.