@leokitten you say a steady state of the drug is required to inhibit growth and replication but there are several abx that have very short half lives of a few hours which are dosed twice a day which are effective. Also with valcyte dosing, during different times of the course of treatment the drug is either given twice a day and even once a day. Valcyte has a 4hr half life so dosing once or twice day the steady state is out the window but the drug is effective. Going by what your saying than valcyte should be dosed 4hrly. I would assume there is more to just a steady state. Also a steady state and blood levels do build up to a certain level overtime of a few days. Your correct in that famvir half life is 2hrs not 4hrs but I pulled that figure out of my pocket as a guess or approximation. The main reason it was even mentioned was only to compare it to the much longer intracellular half life.
so your statement of valtrex and famvir working the exact same way is null and void when u take into the account of doctors being guided into switching patients showing viral resistance to valtrex and putting them on famvir. If they truly were the same then this recommendation wouldn't have been made. Maybe they need to relable all the boxes the same. Oh but valtrex u said was stronger, maybe label it valtrex forte.
so if famvir has an intracellular half life of 18hrs, ,why would one need to dose it more than twice a day? Seems like a waste.
why would the speed of replication not be a factor of a virus and it's treatment. In combination with half lives of drugs this would be important. One needs to marry up the frequency of viral replication to make sure there is enough antiviral in the body to have an effect.
I wouldn't say valtrex is stronger than famvir, maybe for different viruses but anecdotally famvir seems to work more efficiently for many viruses that causes issues for cfs. My personal experience and from others on this forum shows that they get better response from famvir for ebv/cmv/hhv6. When I use valtrex only all I get is increased viral symptoms and increase in lymphocytes and cd8 t cells, which says to me valtrex isn't cutting it. But on my paltry dose of weak famvir twice a day is enough to knock this virus back wards.
Also famvir is regarded as the antiviral of choice over valtrex for shingles infections. As you have stated valtrex is the pro drug of acyclovir which as been around much longer, research is showing more viral resistance to acyclovir and it's recommend when this happens to change the patient to famvir. so because the above situation is recommended in many medical books ,there's a possibility of being some synergy, but it's all speculation.
If what your saying was true about famvir and valtrex having the same target than this would also make it invalid to use valcyte with either famvir or valtrex ,as valcyte was designed from acyclovir.
The point of using valtrex and famvir together is we don't really know if there is a synergistic effect ebv/cmv/hhv6 but if cost wasn't a problem, I assume they would be safe together as either of them have been combined with other drugs as well as valcyte.
Due to financial reasons, many can't afford to take large dose multiple times a day so have used lower doses twice a day and improved. These doses are very similar to suppression therapy used in genital herpes infections as well as organ transplant prophylaxis for cmv. Again the steady state drug levels don't seem to apply here.