I'm a woman over 50 on sustiva and truvada for over two years with good results. Now my dr. says she's concerned about my kidneys and that I might consider taking truvada every other day. She says it's my decision so I'm trying to do as much research as possible before deciding. She also says drug resistance is a possibility but that this is now a trend with truvada for those over 50. What is your opinion?
Your doctor is correct that dose adjustment for the components of Truvada, which are tenofovir and emtrictabine, is recommended in the presence of some degree of renal insufficiency. The specific dose change is in Table 15 of the current HHS Guidelines, to which the web link is noted below. A change to every other day dosing is advised by the manufacturer when the degree of reduction in the creatinine clearance, which is a measure of renal function, is reduced to a level of 30-49 ml/min. Further dose reduction is recommended for even poorer renal function with lower creatinine clearances.
Such dose reductions are recommended to avoid unnecessary increases in the levels of these two drugs in your blood in the presence of impaired renal function, and to reduce any further damage to your kidneys, or other toxicity that might result from increased blood levels.
In the event that dose reduction is undertaken in this manner, there is no reason to think that you are more susceptible to resistance than a person with normal kidney function who takes the standard dose, because the drug levels achieved in the blood are the same.
I can't answer the specific question in your case, because you did not mention whether or not you have any decrease in your renal function. Because your doctor is suggesting this dose reduction, I would guess that you do, but I suggest that you take your concern with this response to your next visit to clarify the reasons for this recommendation.
I would not advise reducing the dose of your Truvada only on the basis of your age, if your renal function is normal, because that might put you at an increased risk of resistance to both tenofovir and emtricitabine due to low blood levels of these drugs with the reduced dose.
An additional reasonable question to ask your doctor is, if you do have some degree of kidney damage (i.e. impaired renal function), what are the alternatives to the use of tenofovir? Many HIV clinicians prefer to use other drugs in that setting in order to avoid renal toxicity from tenofovir, which occurs most commonly among patients who already have some degree of impaired renal function.
As always, I urge you to talk to your doctor about these issues.