How Will My Doctor and I Know What Medications to Use Next?

Before changing your treatment regimen, your doctor will try to find out why your current regimen is not working (see HIV Treatment Regimen Failure Fact Sheet for causes of regimen failure). Your doctor will evaluate your adherence to the regimen, the regimen's tolerability, and drug interactions. Whether you and your doctor decide to change your regimen and what new medications you will take will depend on why your current regimen is failing.

What Is Adherence?

Adherence refers to how closely you follow (adhere to) your treatment regimen. If your regimen is failing because you cannot adhere to it, you and your doctor should discuss why you are having difficulty taking your medication and what you can do to improve your adherence. Your doctor may change your regimen to reduce the number of pills you take or how often you take them. For more information about adherence, see What Is Treatment Adherence? and Adhering to My HIV Treatment Regimen Fact Sheets.

What Is Tolerability?

Tolerability refers to how many and what types of negative side effects you experience while taking your medications. If the side effects are severe, you may need to change your regimen. Your doctor will ask you what side effects you have and how long you have had them. You and your doctor will decide whether to treat the side effects or to change your anti-HIV medications.

What Are Drug Interactions?

Anti-HIV medications may interact with other medications you are taking. This may reduce the effectiveness of the medications or increase the risk of negative side effects. You and your doctor should review all of your medications, including over-the-counter medications and herbal remedies. You should also review whether your medications should be taken with food or on an empty stomach.

Changing Regimens

If your regimen is failing and you and your doctor have ruled out adherence, tolerability, and drug interactions, you should consider changing your regimen. Before changing anti-HIV medications, talk with your doctor about:

• anti-HIV medications you have taken before
• the strength of the new medications your doctor recommends
• possible side effects of the new medications
• how well you will be able to adhere to the new regimen
• the number of anti-HIV medications that you have not yet used

Your doctor will confirm that your regimen is failing with at least two viral load tests and three CD4 counts. You should also be tested for drug resistance while you are taking the failing regimen.

In general, your new treatment regimen should include three or more medications. You and your doctor will choose the medications based on your medication history, results of resistance testing, and side effects you have experienced. If you have already taken many of the FDA-approved anti- HIV medications, your doctor may recommend a new medication currently under investigation. You may be eligible to participate in a clinical trial using these medications or new treatment strategies. For more information about participating in a clinical trial, ask your doctor, or visit the "Clinical Trials" section of the AIDSinfo Web site at http://aidsinfo.nih.gov/ClinicalTrials/.

For More Information

Contact your doctor or an AIDSinfo Health Information Specialist at 1–800–448–0440 or http://aidsinfo.nih.gov.

Terms Used in This Fact Sheet CD4 count: CD4 cells, also called T cells or CD4+ T cells, are white blood cells that fight infection. HIV destroys CD4 cells, making it harder for your body to fight infections. A CD4 count is the number of CD4 cells in a sample of blood. Drug resistance: HIV can mutate (change form), resulting in HIV that cannot be controlled with certain medications. Viral load: the amount of HIV in a sample of blood.

This information is based on the U.S. Department of Health and Human Services' Guidelines for the Use of Antiretroviral Agents in HIV-Infected Adults and Adolescents (available at http://aidsinfo.nih.gov).