General Resistance Questions

• Is Drug Resistance Inevitable?
  I know that people who don't take their HIV meds consistently are likely to develop drug resistant mutations. What about people who never fail to take their meds? I'm aiming for 100 percent compliance. Should I expect to develop drug resistance eventually?
  Response from Renslow Sherer, M.D. (July 16, 2006)

• How Dangerous Is Stopping Your Meds Without Informing Your Doctor?
  Three weeks ago my partner stopped taking her meds without telling her doctor. She's done this before. I'm worried that she might develop multi-drug resistance.
  Response from Renslow Sherer, M.D. (September 19, 2006)

• Do All HIV Mutations Cause Drug Resistance?
  A genotype test showed that my strain of HIV continues three mutations, but my doctor says he isn't worried about them, which confuses me. Are mutations ever harmless?
  Response from Renslow Sherer, M.D. (March 30, 2006)

• How Can You Tell Whether You Have Developed Drug Resistance?
  When an HIV-positive person switches to new meds, how long does it take to determine whether they are resistant to any of the new drugs? Are there any signs one should look out for?
  Response from Renslow Sherer, M.D. (October 22, 2006)

• How Important Is an Undetectable Viral Load?
  My CD4 count is consistently in the 950 to 1,000 range and I feel great, but after more than two years of treatment my viral load has never dropped below 356. I'm taking Kaletra (lopinavir/ritonavir), Viread (tenofovir), Epivir (3TC, lamivudine) and videx (ddI, didanosine). Testing shows I have no resistance. If my immune system remains strong and my doctor monitors my condition regularly is there any need to worry about a detectable viral load?
  Response from Renslow Sherer, M.D. (April 27, 2005)

• What Percentage of New HIV Infections Are Drug Resistant?
  What are the chances that a newly-infected person who hasn't taken drugs yet has a drug-resistant form of HIV? If somebody is resistant to a class of drugs will the person he or she infects be resistant to the same drugs?
  Response from Renslow Sherer, M.D. (August 28, 2006)

Resistance Testing

• Genotypic vs. Phenotypic Testing
  Could you explain the advantages and disadvantages of phenotypic and genotypic resistance testing? Also, what's a virtual phenotype? Which do you use and why?
  Response from Renslow Sherer, M.D. (May 24, 2004)

• Do all HIVers Need Phenotypic Resistance Testing?
  How does phenotypic testing work? Is this kind of testing necessary for everyone with HIV, or is it only recommended for people who have been on lots of regimens and have multiple mutations?
  Response from Renslow Sherer, M.D. (August 24, 2004)

• Are Old Mutations That Don't Appear on Recent Tests Really Gone?
  In my latest genotype test, mutations that showed up eight years ago seemed to have disappeared completely. Are those mutations really gone, or are they still lurking somewhere? If those mutations are still there, can the genotype test really be any good?
  Response from Renslow Sherer, M.D. (September 14, 2006)

• Resistance Testing When Treatment Isn't Necessary
  Since I was diagnosed with HIV nine months ago my viral load has ranged from 128 to 1,600 and my CD4 count has been between 400 and 554. My doctor tells me I don't need to start meds yet, but I do need to get a resistance test. Why?
  Response from Renslow Sherer, M.D. (July 16, 2006)

• What Is Replication Capacity?
  I have been infected with HIV for 15 years and I just heard a new term -- "replication capacity." What does it mean? How can the replication capacity of HIV be tested?
  Response from Renslow Sherer, M.D. (August 24, 2004)

Drug Resistance and Treatment

• What Are the Options For People With Highly Resistant HIV?
  I have been HIV positive since 1988. Unfortunately, in the 1990's I got into street drugs and didn't take my meds consistently. I'm sober now, but my HIV is highly resistant. My viral load is over 100,000 and for three years my CD4 count has been around 10. Nothing seems to work. What's your advice for someone like me, who has tried everything available? Where can I find new effective meds?
  Response from Renslow Sherer, M.D. (April 27, 2006)

• Resistance-Proof HIV Meds?
  The last time I visited my doctor I was told that in just the past few months their office has seen eight new HIV-positive patients who are resistant to all available meds -- and none of them were older than 25. They are on a waiting list for three new drugs coming out next year, my nurse says. Now I'm wondering: Are there any drugs under investigation to which HIV could never become resistant?
  Response from Eric Daar, M.D. (November 18, 2006)

• I'm Doing Everything Right; Why Is My Viral Load Increasing?
  In four months my viral load has surged from undetectable to 48,000. I had been doing well with a regimen of stavudine (d4T, Zerit), 3TC (lamivudine, Epivir), efavirenz (Sustiva, Stocrin) for several months before this huge increase. I never missed my meds. I don't drink or smoke. Why has my viral load changed so rapidly?
  Response from Renslow Sherer, M.D. (April 27, 2006)

• Is Slow CD4 Count Recovery a Sign of Drug Resistance?
  Early last summer I learned I was HIV positive and had a CD4 count of 109. I was started on Sustiva (efavirenz, Stocrin) and Truvada (tenofovir/FTC) immediately. A month later my viral load was undetectable, but my CD4 count was only 142. I just learned that three months later my viral load remains undetectable but my CD4 count is 150. I am wondering if this slow progress is a sign of drug resistance. Should I think about switching drugs?
  Response from Renslow Sherer, M.D. (December 4, 2006)

• My Viral Load Is Up; Is the Increase Due to Drug Resistance?
  I have been on a triple combination of d4T (stavudine, Zerit), 3TC (lamivudine, Epivir) and Sustiva (efavirenz, Stocrin) for two years. My viral load has consistently been undetectable and my CD4 has been above 550. About six months ago I had a four-day unscheduled treatment interruption. My latest test results showed my CD4 is down to 421 and my viral load is up to 780. Have I already acquired resistance?
  Response from Renslow Sherer, M.D. (March 15, 2006)