Choosing a Drug Combination
Part of A Practical Guide to HIV Drug Treatment for People Living With HIV
The ideal treatment for HIV is one that:
A single antiretroviral drug is not powerful enough to suppress HIV on its own; it has to be taken in combination with other antiretroviral drugs. Years of experience with dozens of different drug combinations has given us a huge amount of information on each combo, including overall survival rates, how it affects viral load and CD4 count, its side effects and long-term toxicities.
This leads us to suggest one more goal for the "ideal" combo: it should be easy to choose. The number of anti-HIV drugs, and the number of possible ways of combining them, is growing all the time. Fortunately, we know which combinations are best to start with. Earlier (see "How Do We Know Which Treatments Are 'Best'?"), we described how expert panels assemble the information from clinical trials into treatment guidelines. Guidelines usually rank drug combinations, often using terms such as preferred, alternate, and acceptable. A drug combination's ranking indicates how well it rates in terms of several criteria, including how well it suppresses viral load over the long term, the ease of its pill-taking schedule, and its risk of major side effects or toxicity.
This ranking system can help differentiate the multitude of possible combinations. It is meant to guide, not to replace, decisions made by you and your doctor. A so-called "alternate" combination is not necessarily "second best." It may turn out to be the best choice for you.
In the end, the ranking system aims to make the selection process much simpler. Rather than sifting through a bewildering number of possible options, HIV-positive people and their doctors can usually choose between a tried-andtested few, especially for first combinations.
Building a Combination
Antiretroviral drug combinations are built using drugs from different groups, or "classes." Each class of anti-HIV drugs attacks HIV in a different way. Researchers have discovered that it takes three different drugs from at least two classes to effectively suppress HIV. Clinical trials have taught us that an effective combination includes a "backbone" of two drugs from one class plus a third drug from another class.
If you want to know more about the different drugs in a combination or the theory behind how combinations are chosen, check out the appendices at the back of the guide.
In this discussion of choosing a first combination, we will start by presenting the first-time combinations recommended at the time we published this guide. In the rest of this section, we'll concentrate on the factors to consider and the questions to ask when considering a new treatment combo. These will always be relevant even as the specific options vary over time.
Choosing your first combination is such an important topic that we think it is worthwhile to present the current information on recommended choices, even though recommendations may change over time. Knowing the currently preferred combinations will help you and your doctor make the best choice. You can contact CATIE (at 1-800-263-1638 or www.catie.ca) for the most up-to-date information.
A word about drug names before we start. Prescription drugs have two names: a common name, which describes the active ingredient in the drug, and a brand name, which is used to market the drug. (Brand names are always capitalized.) Antiretroviral drugs can be even more complicated because they are sometimes called by a three-letter abbreviation.
I never really chose my meds; it was the doctor who did the choosing. ... Basically, she left the room, wrote out the prescription and put it in my hand. I wasn't even given any options. I didn't ask questions -- I figured the doctor knows what she's doing. I think I put too much faith in the doctor. There could be something out there that's better for me, but nobody's ever given me the chance to talk about it.
Also, some pills contain more than one drug. In this guide, we mention the common and brand names of each drug the first time we talk about it. After that, we use the most common name. If it all gets too confusing, Appendix B lists all the common and brand names of antiretroviral drugs currently available in Canada.
At the time this guide was published, most HIV treatment guidelines recommended the following first-time combinations:
Some guidelines also recommend the following first-time combinations:
You can find more information about these drugs in the appendices (or in up-to-date fact sheets from CATIE or other sources).
Remember, that while these are the recommended combinations, this does not mean that other combinations are not as effective or that another combination may not be the best one for you. In the next section, we talk about some issues to consider as you and your doctor choose your drug combination. (Appendix D covers some more of the reasons why you might choose one combination over another.)
Which Combination Is Best for You?
Although choice can be a good thing, it can also be frustrating: "How should I know which to choose?" is a common complaint among HIV-positive people trying to pick a treatment combo. However, some of those decisions may already be made for you. Depending on your medical situation, some drugs may not be allowed or some may be more suitable than others.
Here are some of the most important things to consider. You may not know whether these apply to you, but you can use this list to bring up topics with your doctor.
Drug-resistant forms of HIV can sometimes be transmitted from person to person. Therefore, you may already be resistant to some medications even if you have not taken them before. Guidelines recommend that all HIV-positive people have a resistance test done before they start treatment. Resistance testing is not perfect, but it can identify specific drugs that may not work for you. This allows you and your doctor to choose other drugs that are more likely to work. (See the discussion of drug resistance in Appendix E.)
You may be allergic, or hypersensitive, to certain drugs. For example, many people are hypersensitive to abacavir (Ziagen, also found in Kivexa and Trizivir). A simple blood test, done before you start treatment, can determine whether you're likely to have a potentially dangerous hypersensitivity reaction to abacavir (see the CATIE Fact Sheet on "Abacavir Hypersensitivity Screening" if you want more information on this subject). If so, you can cross it off your list of choices. You may also be hypersensitive to other antiretroviral drugs, so ask your doctor about the signs of a hypersensitivity reaction so that you can seek medical help should you react to a drug. There are no tests for any medication other than abacavir that will indicate a possible reaction.
Other Medical Conditions
Certain drugs may not be recommended if you have hepatitis B or C or other liver problems, kidney damage, tuberculosis, depression or other mental and emotional health issues.
This article was provided by Canadian AIDS Treatment Information Exchange. Visit CATIE's Web site to find out more about their activities, publications and services.
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