A Revolutionary New Way to Fight HIV/AIDS: CCR5 Inhibitors

Selzentry, the First CCR5 Inhibitor

In August 2007, the U.S. Food and Drug Administration approved the first CCR5 inhibitor, Selzentry, for use in treatment-experienced patients. Studies of Selzentry have mostly focused on people who have been on a lot of different HIV treatment regimens and who have CCR5-tropic HIV. These studies have shown that, when Selzentry is taken in combination with other HIV drugs, the regimen is far more likely to work than if a person took those other HIV drugs without Selzentry.

How Is Selzentry Taken?

Selzentry is a pill that should be taken twice a day. It is available in 150-mg and 300-mg tablets. The proper dose will depend on what other HIV medications you're taking, because different HIV meds can affect how well Selzentry works in your body (and vice versa). For example, if you take a protease inhibitor, such as Prezista (darunavir, TMC114) or Kaletra (lopinavir/ritonavir), your doctor or pharmacist will probably give you a lower dose of Selzentry. If you take Atripla (efavirenz/tenofovir/FTC), Intelence (etravirine, TMC125) or Sustiva (efavirenz, Stocrin), your doctor or pharmacist might give you a higher dose of Selzentry.

HIV medications aren't the only type of drugs that Selzentry may interact with. So, as always, you should make sure your doctor knows about all of the medicines and supplements you use -- whether they're prescription meds or over-the-counter -- before you get a prescription for Selzentry.

As far as researchers know, there are no special risks associated with taking Selzentry while using tobacco, alcohol or recreational drugs. However, all of these substances can harm your body and interfere with your ability to take your HIV meds consistently, so it's also important for you and your doctor to discuss any substances you use before you start Selzentry.

Side Effects

Research on Selzentry to date shows that the drug only causes mild side effects, and even those only occur in some people. People taking Selzentry may experience cough, fever, dizziness, headache, low blood pressure, nausea and bladder irritation.

Fortunately, Selzentry has not been associated with body shape changes or cholesterol/triglyceride problems. However, Selzentry should be used with caution in people who have liver or heart disease, since it can potentially worsen these problems; be sure to talk this over with your doctor.

Also, it's worth noting that Selzentry was approved pretty recently, so we're far from knowing everything there is to know about the drug and its possible side effects. It's also the first CCR5 ever approved on the planet, so there may still be some questions about it. But there are other CCR5 inhibitors under development that have shown excellent results, so this is an exciting new type of medication that most health care providers are learning to use.

For More Information

This article is meant to get you started on the road to learning more about CCR5 inhibitors. If you'd like more information, try visiting these other resources on our site:

• Frequently Asked Questions About Selzentry
• A New Way to Fight HIV: CCR5 Inhibitors: An Interview With David Hardy, M.D.
• Browse Articles on the Basics of Selzentry
• Browse the Latest News and Research on Selzentry

Lowdown on How the Different Types of HIV Medications Work All HIV wants to do is make more copies of itself. Picture it setting up breeding factories inside your CD4 cells. CCR5 inhibitors act like a lock on the factory door that prevents HIV from getting inside. Fusion inhibitors act like a stuck hinge preventing HIV from getting inside the CD4 cell once the door has been opened. Integrase inhibitors act like tricksters who hide the factory's blueprints. NNRTIs and Intelence act like bad supervisors who give the wrong instructions to HIV during the building process. NRTIs act like broken building blocks so that the factory HIV tries to build in your CD4 cells is made with broken bricks. Protease inhibitors act like workers who put defective parts in each new virus being built on the factory's assembly line.

Terms to Know CCR5 inhibitor - A CCR5 inhibitor, also known as a CCR5 antagonist, is a type of medication that prevents HIV from using the CCR5 coreceptor to enter a CD4 cell. CCR5 tropic - HIV that can only use CCR5 (or R5) coreceptors. CD4 cell - A CD4 cell is the type of white blood cell that HIV targets. Coreceptor - To get inside a CD4 cell, HIV must trigger a coreceptor on the cell's surface. Think of the coreceptor as a keyhole: Once HIV has released the lock, it can slip inside the CD4 cell and do its damage. CXCR4 tropic - HIV that can only use CXCR4 (or X4) coreceptors. Dual tropic - HIV that can use both CCR5 and CXCR4 coreceptors. Mixed tropic - A combination of CCR5-tropic and CXCR4-tropic (and maybe even dual-tropic) HIV. Tropism - HIV uses two kinds of coreceptors to enter a CD4 cell: CXCR4 and CCR5. The type of coreceptor that HIV uses to enter a cell is called its tropism.