I went drinking at MilkBoy Philly first thing Monday morning. I have some regrets

As the patron saint of day drinkers, Jimmy Buffett, reminds us, it's always 5 o'clock somewhere.

Unfortunately, when I arrive at MilkBoy Philadelphia — its garage doors rolled open to the sounds and aromas of trash trucks and delivery vans clogging the intersection of 11^th and Chestnut Streets — it is, undeniably, 7:30 Monday morning.

You wouldn't know it, though, from the incongruously lively crowd at this 21^st-century take on an old-school Philadelphia mainstay: a third-shift bar, targeting not weary overnight factory workers but doctors and nurses coming off graveyard shifts at Thomas Jefferson University Hospital. Still in scrubs, with ID tags dangling from lanyards, they're throwing back craft beers and sharing baskets of nachos as though it were not the most misery-inducing time of the week but rather one worthy of the designation "happy hour."

With just over an hour to spare until I'm expected at the morning news meeting, I make my way into this reenactment of Joe's Bar from Grey's Anatomy and slide onto one of the few empty bar stools. In addition to hospital workers, the mix includes firemen in matching T-shirts, a table of tourists just off an overnight Greyhound bus, and a handful of regulars who, it turns out, are merely folks who appreciate a crisp glass of white wine on the way into the office.

I'll later learn there is a breakfast menu, but for now, the bartender passes me the drink menu without comment or judgment. I order a Guinness, because it is low in alcohol and is, at least, the color of coffee.  A couple of friends — just the right combination of degenerate and early riser to join me on this expedition — select tall cans of Miller High Life for reasons I cannot explain.

This scene wasn't the plan when MilkBoy owner Bill Hanson added the 19-hour-a-day Center City location six years ago — an artfully gritty, rehabbed industrial space with a music venue upstairs and a wash of yellow light across everything.

"We opened up thinking we were going to do a breakfast business from the hospital," he said. Then, he said, he realized hospital staff were looking for a place to party. "It's their 5 o'clock in the afternoon. It just happens to be 7 in the morning. Then we realized there are other third-shifters around — hotel concierge, maintenance people."

It turns out plenty on the menu has crossover potential. There's a drink called "the Waiting Room," made with coffee, Frangelico, and peppermint schnapps ($10), and a popular breakfast burrito with eggs, cheese, potatoes, refried beans, and pico de gallo ($8). The top-selling item on the menu, the Hangover Burger, comes with a fried egg (but not ibuprofen). Also, it appeared to be a popular consensus that there's no wrong time of day for a shot of Jameson.

As a way to wind down the weekend, a trip to the bar has its benefits. "It actually takes the edge off a bit," my friend Ryan says. But by 9 a.m., most customers have gone home to bed — or, perhaps, in to work. We leave, too, stepping out of the bar and back into the glare of Monday morning.

1100 Chestnut St., 215-925-6455, milkboyphilly.com

When to go: If your aim is to mingle with medical professionals, stop by around 7:30 a.m. Monday, Thursday, or Friday, the peak early-morning hours. It opens at 7 a.m. Monday through Friday, and 11 a.m. on weekends, and closes at 2 a.m. The kitchen opens at 8 a.m.

What to order: You do you. For teetotalers, the coffee, roasted by Dallis Bros. Coffee in Queens, is an excellent choice.

Bring: The medical residents, retirees,  and third-shift workers in your life. Breath mints if you're heading into the office afterward.

Bathroom situation: A couple of subway-tile-covered, single-stall units that won't inspire you to linger — but that won't repel you, either.

Sounds like: A rowdy 96 decibels of hospital gossip, accessible rock music (Beck, the Raconteurs) and traffic noise roaring in from 11th Street.