I use Phenobarbital regularly and think it is superior to Lorazepam. Ativan is the equivalent of alternating slamming the gas petal and the break. You typically end up with irregular dosing with Ativan depending upon subjective nursing CIWA calculations and timing of their evaluations. I think Ativan just leads to worsening delirium. We've all done the Ativan benzo hammer and seen the spiral down before you intubate. You really want a long acting GABA agonist. If not using Phenobarbital, then I think Diazepam is also preferable to Lorazepam.
I equate it to treating hypertension emergently with boluses of Hydralazine instead of a Nicardipine infusion. You end up with a much smoother and safer effect rather than wild swings up and down.
I typically give 260 mg of Phenobarbital for mild alcohol withdrawal followed by another 130 mg in 30 minutes if still signs of withdrawal. I'll treat with 10 mg/kg right off the bat for severe withdrawal obviously requiring admission that looks like potentially headed to the ICU. A lot of times this averts ICU admission.
People have valid concerns regarding Phenobarbital use in discharged patients. I do use more regularly for admitted patients, although not infrequently I'll also use for a patient that I think might improve enough for outpatient management. That's also why I prefer starting with lower doses for mild withdrawal. I have yet to have someone that I know of go out and immediately drink significantly on top of Phenobarbital resulting in severe respiratory/neurological depression or a bad outcome.
Groove is correct that the inpatient teams are usually less familiar with Phenobarbital. I find though that they see patients doing better and don't have a problem with it. They can subsequently treat alcohol withdrawal however they feel comfortable on the floor or in the ICU. I believe that they end up using fewer doses of benzodiazepines following ED treatment with Phenobarbital although can only speak anecdotally.
This has been out for a while, but helpful for further reading and those not familiar:
Phenobarbital for Acute Alcohol Withdrawal: A Prospective Randomized Double-Blind Placebo Controlled Study