Why don't addicts get large doses of intravenous NAD+ by default? That would alleviate 90% of their addiction inside brain as they are typically brutally NAD+ d

Why don't addicts get large doses of intravenous NAD+ by default? That would alleviate 90% of their addiction inside brain as they are typically brutally NAD+ depleted and on the hunt for anything that raises NAD+/FAD+ in the brain.