No, actually. Taking naltrexone daily is better than nothing -- it was originally marketed as an anti-craving drug, and it's not completely useless in that respect -- but it's most effective when taken an hour before drinking alcohol.
Imagine a rat who has learned to press a lever to get peanut butter. His life in a cage is pretty boring, so he presses the lever all day long. At some point he will be thoroughly conditioned to press the lever, and will keep pressing it even if moved to a better environment with lots of climbing and rat toys and such. He's addicted.
The rat will keep seeking that lever, because he's addicted to it. He can unlearn the addiction, but the lever must be available for him to do that. If he presses the lever and nothing happens, he'll gradually turn his attention to other things.
That lever must be there, though. If the lever is simply removed then he may do other things, but he'll be back pushing that lever as soon as the lever is reintroduced.
He can't unlearn his addiction to the lever without pressing the lever futilely. The lever -- in our case, the alcohol -- must be present in order for him to learn that the lever no longer produces peanut butter.
If he presses the lever without getting peanut butter, his addiction will be extinguished over time. If he doesn't have the lever at all, the addiction will simply lie dormant.