Pro re nata or PRN is a medical phrase used to indicate to take a medication as needed.

Pro Re Nata

It started with a rattle.

Wait, back up.

Really, it started with Mary Campbell and the deal she made with Azazel for John Winchester's life, years before Dean was even a twinkle in his dad's eye. That deal led to Sam's psychic crap, which lead to a showdown with Azazel, which led to Dad's deal. That deal led to a showdown with a bunch of psychic kids, which led to Sam's death and Dean's deal, which lead to his own death, Hell, and Sammy exorcising demons with the power of his brain. And that led to the Apocalypse.

Sure, the Apocalypse got called off on a technicality, but the end results were clear. There was a lot of mess to clean up, and Team Winchester was on the case. Dean had made it sort of his life's mission, saving people. Sam had unresolved guilt issues, what with the unleashing of Lucifer and everything, and while they were on the subject, some of that was Dean's fault as well. Everyone had their own part that they played. Dean breaking the first seal, Sam breaking the last, and Cas...

Well, Cas had issues with letting it all happen.

Which led to the rattle.

Sammy drove, and Dean rode shotgun. They were on their way, well, to somewhere. Dean wasn't entirely certain where. He'd had a late night and was drowsy and hungover, had his shades pulled low when Cas appeared in the back seat. He tuned out the low drone of voices, pitched so that it wouldn't bother him. He got that there was something big, something evil in Connecticut that needed to be killed before it took over an entire city, but the details were lost on him. That was Sam's area of expertise.

"Dean," Cas said, close to Dean's ear. Dean lifted the shades and blinked at him in response. Maybe his face said it all already, but Cas just kind of licked his lips and continued on, "There's a rattle in your car."

Whoa. Hold it. A rattle in his car? Even the end of the world wasn't the end of the world, but if his baby was making funny sounds? That there was the end of his world.

"Pull over," he told Sam.

"Dean, we're on a job—"

"Danbury will still be in peril in a couple of hours," Dean pointed out. "And in a couple of hours, that rattle could be something serious."

Sam looked over his shoulder at Cas, heaved a sigh, and pulled over. He punched the brake a little hard, and the Impala jerked to a stop, and then Dean heard the rattle, too. He identified it easily, for two reasons. One, because it was the sound of pills rattling in a bottle, and two, because when Sam jerked the car to a stop – something Dean was going to bitch at him for, later – the bottle flew out from under the driver's side and hit Sam in the ankle. Karmic justice. Dean approved.

"What the..." Sam muttered, and picked it up.

When he looked over at Dean, his face said it all. Dean grabbed the bottle away, but didn't bother to glance over the label because, yeah, he remembered what it was. That was the last bottle of his lopram, filled while Sammy was busy trying to keep him out of Hell. Not that either did much good for him. At that point he was medicating himself with more tequila than anything else – the bottle was still mostly full.

Dean opened his door, stared out into the open expanse of Iowa's flatlands, and threw the bottle as hard as he could.

"There," he said, once he was back in the car. "The rattle is fixed. Now, tell me more about Connecticut."

"Dean," Sam said, in that I'm-a-poor-kicked-puppy-who's-going-to-chew-your-ankle-off-unless-you-talk tone of his.

Dean didn't like talking about his feelings at the best of times. When the sharing and caring was about his pharmaceutical use? Yeah, right. "Drive, Sam."

"Dean," Sam said again.

Dean dropped his shades again, burrowed into the depths of his coat, and pretended to sleep. He was pretty sure Sam knew he was faking, and Cas had to know with that weird semi-angelic knowing shit thing of his, but Sam let it drop, and Cas was pretty decent at following a lead when he saw one. He fell asleep for real as they were about to cross the Indiana-Ohio border.

They took care of the thing in Dansbury – some creature with tentacles that resembled Cthulhu – and spent the night in an abandoned bed and breakfast along the coast. Sam hadn't said anything about the pills, but it was coming. The kid was persistent, never gave up on much of anything.

So it blindsided him when Cas caught him on the way to the bathroom and produced the bottle he'd left in Iowa.

"You need these," Cas said.

"No, I don't," Dean told him. He tried to shove the bottle back at Cas, but the guy held his ground and the bottle wound up on the floor, little white pills spilled all over the place.

"You do," Cas said, and he kind of sounded helpless about it all.

"If this is your knowing shit thing at work again, so help me—"

"This isn't about me, Dean. This is about you and the things you need."

Dean kicked the bottle away. "I don't need those. Haven't needed them in a while." He stepped over the pills and walked away. The trip to the bathroom got detoured, and he wound up at a local bar instead. The bar had those Purple Nurple things he liked, though when he woke up the following morning, all he could remember was a name – Candi with an "i" – and how much he'd puked the last time he drank too many Purple Nurples.

He lurched his way into the kitchen, where Sam had three steaming cups of hot coffee and some greasy eggs waiting on the table. Dean shoved the food away before it made him sick again, and reached for the coffee. Sam just sat there, watching him over the top of his laptop.

"Esciltalopram," he said by way of greeting.

"The fuck are you talking about?"

Sam closed the laptop and pursed his lips in that irritating way he had, like he had all the answers in the world. "The pills, Dean. They were—"

"Whatsis-lopram," Dean supplied. "I know what they were, Sammy. What's your point?"

"Esciltalopram is more commonly known by its brand name, Dean, Lexapro. It's an antidepressant."

"Sam. Point. Now."

Sam licked at his lips, and Dean suddenly realized that Sam was nervous. It didn't excuse his acting like a total bitch, though. "When were you going to tell me you're on antidepressants?" Sam asked.

"I'm not. Look, you and Cas need to stop with the intervention crap, because you suck at it."

Sam jumped to his feet and started pacing. "This isn't an intervention, Dean. This is serious. That's some major shit you're on."

"Was on," Dean corrected. "I haven't taken any in a while."

"Yeah, but the drinking? The mood swings? Tell me that's fine, Dean, because I don't believe it."

"I went to Hell so you could be alive and breathing, Sammy. Hell." He shook his head, slowly because there was a funny ringing in his ears. "That means I'm kind of entitled to drink too much and have mood swings. I spent more time there than I spent alive. That's not the sort of thing that you can just wish away. But I deal with it. Because I can't do anything but deal with it."

"Dean," Sam said, and then Dean shoved himself away from the table and the conversation. One cup of coffee tipped over and spilled all over the stained tablecloth, but neither Dean nor Sam made any move to clean it up. "Dean," Sam said again, like he was one to talk about emotional stability and all that shit, either.

"Sam," Dean replied, a warning

"Is this a bad time?" They both swung towards the doorway, where Cas was standing, brow furrowed. "If you two need time alone, I can go."

Dean made for the door, brushed past Cas without saying anything. His mouth was sour, and the coffee hadn't made it any better, so he went to the bathroom and leaned over the toilet for a while, waiting for the dry heaves to stop. Then he brushed his teeth, and washed the taste of vomit out of his mouth.

Sam dropped the subject long enough for Dean to let his guard down. They went to Maine to track down a homicidal lobster-man, drove through Canada to get to Michigan, where an amarok was eating people, and then took on a woman in white in Idaho.

Sam was driving again, because that bitch woman in white knocked Dean down a flight of stairs and sprained his ankle in the process. His foot was swollen and dark purple, but the pain was under control with some really good drugs the emergency room had provided. Dean felt loose and limber, observed the world through a warm, happy haze.

"So," Sam said. "How long?"

"How long what?"

And there Cas was in the back seat again, waving around that stupid fucking bottle of lopram. "He means these," Cas supplied helpfully, in just such a tone that Dean could tell Sam had coached him.

The warm, happy haze became murky and disjointed. "You two really don't know when to leave well enough alone, do you?"

"Just tell me," Sam said, and it was his tone there that did it. Dean had locked down a lot of emotions in his life, especially after Hell, but brotherly love was not one of them. It was a low blow, and judging by the look on Sam's face, he knew it was a low blow. "Please?"

Dean scowled and rubbed at his mouth. "Fine. Fine, all right? You guys win. That's my lopram, I took it for a while, but not anymore. There, I fucking talked. Are we done?"

Cas put his hand on Dean's shoulder, reached forward to hand him the bottle. "You need these," he said.

"I still went to Hell, and taking some pills isn't going to change what happened. So, what difference does it make?"

Cas didn't have an answer; he just dropped the pills on the seat next to Dean. The bottle sat there and rattled softly against his leg. He put his hand on it to make the sound stop, and wound up staring at the label.

"Tell me more," Sam said. He was using the Captain Empathy tone of voice, the one he used to get shaken witnesses to spill their inner dark secrets. "Antidepressants aren't like pain pills. The ER doesn't just hand them out."

Dean shrugged and put the bottle back on the seat. "Those low-income clinics will write you a script if you sit with an in-house shrink for an hour." It was better than trying to fake a call from a doctor, or writing his own script, or breaking in and stealing the pills he needed. Less hassle, too. "I got really good at knowing what to say to convince 'em that I needed help. Told them that lopram seemed to work best, that other drugs made me jittery or sick or something. Whatever they wanted to hear. I'd schedule a follow-up, reassure them that I was going to come back, fill the script and leave town."

Sam glanced over at him, then looked over his shoulder at Cas. Dean kept his eyes down, stared at the calluses on his hands.

"This happened after I left," Sam said. Sam was smart, Sam could make great leaps of logic, but Sam was also dead wrong on that front.

"Not everything is about you," Dean snapped. "I was in high school. Sixteen. That weird artsy place in California, the one with the bronze Roman warrior out front?"

"I remember."

Dean shrugged. "They had a therapist. He thought it was his life's mission to motivate me. Made Dad take me to a shrink and everything."

It lay heavy in the air, the thought that Dad had actually taken him. He'd been pissed, that Dean needed something that didn't come from the family, and it drove him into one of those dangerous moods from when Dean was little. Dean had paid for the pills himself, did it in secret so Dad didn't know. Hid them away, crushed them into powder and added them to his coffee, kept them in his shoe, thought he was really clever about it and everything. Dad found out. Dad always found that stuff out. But by then, Dean felt better, slept better, was doing better in school.

Dad decided it was worth the trouble, but left Dean in charge of getting more when he needed it.

"The bottle says it expired," Cas pointed out. "You haven't taken it in a while."

And suddenly, Dean was pissed off again. "Because I was going to Hell, and nothing I said or did was going to change that. I forgot to take it a few times, and then when I remembered, H-day was right around the corner. I figured, you know, what was the point?"

"And when I pulled you out?"

Dean turned in his seat. "You had that angelic healing mojo going on, Cas. You could have fixed it like you fixed everything else. You didn't."

"I didn't know," Cas said, but his eyes dropped and he looked sorry.

"Dean," Sam said, his voice very soft. "I'm your brother. You should have told me."

"What, that I'm the little Zoloft ball from those depression commercials? Fuck that." And that pretty much killed the conversation in the car. For good measure, Dean tossed his favorite Metallica mix in the tape deck and cranked the volume up.

They hunted zombies for a few weeks in Nevada while Dean's ankle healed, stopped by Vegas for a salt and burn, a suicide off the top of a casino, and spent the day after sleeping in a motel decorated in cheap Elvis knockoffs. Dean had trouble sleeping, so when he woke up and Sam was still passed out, he went to grab some coffee and food.

When he got back to the Impala with some greasy Chinese food, Cas was sitting on the passenger side. Dean fished a fortune cookie out of the take-out bag for him. "If I'd known you were coming to dinner, I would have asked you if you wanted an eggroll."

"I can't stay long," Cas said, fidgeting with the cellophane wrap.

"Then why are you here?"

Cas dropped the fortune cookie, took Dean by the wrist and laid a bottle across his palm. "The other bottle, those pills were expired. I got you new ones," he said.

"Cas," Dean started, but Castiel interrupted him.

"You need these."

Dean felt weirdly hot and twitchy, like his skin didn't fit him right anymore. Cas was using his knowing shit thing again, and having it used on him was uncomfortable. "I'm fine," he said, and shrugged Cas's hands away. "So stop it with the gloom and doom. That's my job, got it?"

He started the ignition, and when he looked over again, Cas was gone. It didn't surprise Dean anymore – the move was practically Castiel's trademark. But, again, it made him feel uncomfortable. When he got back to the motel, he found Cas's fortune cookie sitting on the seat, wrapper gone and broken apart, the fortune missing.

"Next time, clean up after yourself," he muttered, and grabbed the bag of food. He didn't go inside, though, just sat there behind the wheel and thought about it. Next to Cas's cookie was the new bottle of lopram. With a sigh, Dean pocketed it and went inside.

Sam was awake and on his laptop, looking up whatever it was that he did there all day. The boy was far too content to sit there and ruin his eyes, but far be it for Dean to tell his brother what should make him happy.

He put the Chinese food on the table, pulled out the fried dumplings and the egg-drop soup and the fried rice and that weird lettuce wrap thing that Sam liked with all the crispy noodles in it. They sat and ate in relative quiet, Dean thinking and Sam typing between bites.

"What if it doesn't work?" Dean blurted out.

Sam lifted his head, looked over the top of his laptop, but his brow didn't wrinkle up, like it did when he was confused. Sam had to know exactly what he was talking about.

Just in case, Dean continued on, "The shit's made for clinical depression, not going to Hell and averting the apocalypse. What if it doesn't work on me?"

"What if it does?" Sam asked.

They didn't talk for the rest of the night.

The motel was cheap, was within walking distance of a few small bars, each with the right kind of atmosphere for hustling pool as well as other things. They stayed put for another few days, did the laundry, and Dean put a fresh coat of wax on his baby, got her shined up real pretty. Mostly, Sam gave him his space, but it wasn't strained. It wasn't like after Hell, when Dean often felt like he was driving with a stranger in the passenger seat.

They packed up after a call from Ellen, another one of those apocalyptic leftovers that were so much fun to deal with. Dean's ankle was its normal size and color again, but just in case, Sam insisted on stopping by a little drugstore to pick up a fresh compression wrap.

Dean sat behind the wheel and waited. The pills were in his pocket, where they'd been since Cas last appeared. Dean had a feeling that if he left them anywhere, Cas would appear and hand them over again. The guy was stubborn, worthy of being an honorary Winchester. Dean thought about what he'd said, thought about need, the crushing kind, like addiction, thought about how he'd needed his father's love, how Sam'd needed to be normal, and how all of them – Sam, Dean, and Cas – needed to find a way to fix everything they'd broken.

Cas was wrong. He didn't need the pills.

When Sam reappeared with the compression wrap, Dean had already made his decision. "One month," he said, and reached over to put the bottle into the glove compartment. He held out a little pill on the palm of his hand and tossed it back, swallowed it dry. "That's how long it takes for this shit to be effective. So I'll give it a try."

"What changed your mind?" Sam asked.

Dean shrugged, pulled out of the parking lot and hit the road. "You know, I was just thinking. I've been off this shit for years, and I've been more or less decent. Not good, but not that bad, I mean, considering. So if the lopram doesn't work on me anymore, it's not the end of the world."

Sam laughed at the irony, quiet and low.

After a while, so did Dean.

Fin.