Hi,
So it seems some experience side effects from taking taf or tdf,bone loss and kidney damage and some don’t experience side effects. How come some do and some don’t ? Is it genetics , lifestyle, big body small body, eating habits ?
Br,
Hi @hepb1,
TAF actually does better at reducing the incidence of bone loss and kidney damage. In my opinion, I doubt it is genetics. It has more to do with how each body processes and absorbs these antivirals. Everyone of us is unique in this way, and probably the reason why some people experience side effects and others don’t. Body size (big/small) could be a factor as well.
Historically, we also know that certain populations are excluded from clinical trials. Such populations could develop side effects because they were not represented in the clinical trial sample such reactions might not be reflected in the results. Since what might work for population/race A without any issue, might not work for population/race B or C in the same way. There is an effort to make sure there is a general representation in clinical trials by different races/ethnicity. Thanks, Bansah1
Dear @hepb1,
TAF and TDF are both prodrugs which are metabolized in the body to form the actual active antiviral compound (tenofovir diphosphate aka TFV). Delivery of TFV to the liver is required for activity in HBV. With TDF (older, cheaper) the drug is exposed systemically and thus gives exposure to both the liver and kidneys. For this reason, the daily dose this drug contains more medicine. With TAF (newer, more expensive), the prodrug form is better taken up by the liver so less drug each day is needed so less drug is exposed to the kidney.
The lower rates of bone demineralization and alteration of kidney function with TAF have nothing to do with genetics of the person taking the medicine nor any life style factors but are simply the result of lower exposure of the kidney to the drug.
It is important to note that the vast majority of patients taking TDF do not experience any symptoms and if they do occur, these are reversed in most cases by altering the TDF dosing from each day to every other day.
This is very important for the patient community to be aware of, especially those in resource challenged areas or who have to pay for their own medication.
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