Dr. My partner has been hiv positive since 2009 and has been indetectable while taking a truvada and zidovudine, but now doctors want to change his meds to truvada and kaletra, is it wise to change meds if they are working allright? According to them Kaletra is "modern" rather than zidovudine.

Thanks for your question.

There are 2 reasons we may want to change meds: First if they are not working to suppress the viral infection (the primary effect of the medicine) or Second if there are side effects or harm that the meds may be doing.

Since his viral load has always been undetectable the meds are serving their primary function.

So a change may be needed if there are side effects. Zidovudine is an older medicine that may cause some effects on the bone marrow (such as anemia...low red blood count) or on the fat (lipodystrophy--which is loss of fat around the face or limbs) or muscles (irritation in the muscles or build up of acid in the blood, called "lactic acidosis"). Some people are more vulnerable to these effects than others and sometimes once the fat changes happen they may not get better or may take years to improve. So many docs recommend a change before the side effects occur. Of course any change to a new medicine may also carry side effects and your partner should go over all the risks/benefits of making a change or staying put. Unless there is some real toxicity from the meds (like acid build up in the blood), there is no emergency and you can have this discussion with his doctors.

Best, Joe