Hmm possibly not - it will be close to it, but since HSV isnt bloodborne
its the compartment where the virus is that you are specifically
interested in. Its just getting a reading elsewhere is rather hard. IIRC
one of those papers I cited does give the saliva peak levels - and thats
actually into and around epidermal tissue - and it was very close if not
indistinguishable to the plasma level. That would suggest a high level of
identity between peak clinical benefit and peak plasma level. This also
assumes that the peak level is required to get best effect rather than it
reaching a threshold of effect at a lower level and the peak simply helps
prolong the time the drug remains above a theapeutic level. I dont know
the answer to that one...but either way a higher peak and a larger Area
Under Curve (a measure you will see in pharm papers) will help to a point.

One cycle of peak level is not the be all and end all however. The virus
life cycle is about 18hrs long and you need to suppress it for a period of
time. Certainly if you pull the drug off in a single cycle growth curve
the virus can then recover - while the body won't be synchronised like an
in vitro test you can draw some fairly direct inferences.

I dont know how often you have to pulse drug into the system for
suppressive therapy as opposed to episodic thereapy. The dosing strategies
for suppressive therapy are tested by observation rather than inference
from the pharmacokinetics.
These dosing strategies have changed over time and looking at the history
I think it works in the manner of try X, if it works good, then try X less
a little and if it works still get it licensed and repeat. This makes it
difficult to define what is actually needed.

There is considerable data now (mostly from Spruance's group) for single
dose treatment of an outbreak with Valacyclovir. There are differences in
the pharmacokinetics of the different drugs so they may explain why this
works (depsite Valacyclovir simply being a delivery system for acyclovir
into the body).

Tim
--
When playing rugby, its not the winning that counts, but the taking apart
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