My understanding, and that outlined in
Stan's Guide, is that the two methods are
equally effective. From my reading, the only difference is that the 48 hour regimen serves as a comforting, gradual process for mental reassurance (
"Some people are concerned about vomiting all of the SN drink and failing. They find comfort going through a two day process to prepare them mentally for the event")
(REF). Note that this does
not mean that the gradual, repeated smaller doses of antiemetic over 48 hours makes vomiting less likely.
It's important to note that the 48 hour regimen ends with the
exact same procedure and timings as that of the stat dose.
After first coming across SN as a method, and reading that the two methods were equally effective, I had naturally been drawn to the simplicity of the stat dose, and so hadn't looked any further at the 48 hour regimen in much detail. Doing so now, I am genuinely unsure why anybody would need to use it. While it has been said that it allows more time to see how the antiemetic is tolerated (especially regarding
EPS), to my mind the flipside is that this
also provides a much longer 48 hour period in which you could experience such negative side-effects, rather than merely in the 45 minutes before SN consumption in the stat dose method. You could also achieve a similar insight by taking a trial dose of meto on a one-off basis, and in the absence of side-effects, use the stat dose method in the future.
Perhaps
@Quarky00 can clarify further, he wrote the various SN FAQ's, and I believe he covers the differences in these two methods somewhere.
