KYIV, Ukraine - The temperature was below freezing and the pharmacy line was way out the door. But Tetyana Dagadaeva could not be deterred. 

For days, she and her 11-year-old son, Oleksiy, had been urgently searching for the insulin he needs to survive. With his supply at home dwindling, they soon would have no choice but to flee the country to keep him alive.

After two hours in the biting wind, the wooden door swung open and a woman in a lab coat shouted out the message Dagadaeva had prayed she wouldn't hear again: They were out of stock.

"My son's life depends on this," she said somberly as she stepped away from the line. Her tears welled up.

As war continues to rage across Ukraine, it is disrupting the flow of crucial drugs and medical supplies. When curfews are lifted each morning, residents of cities nationwide rush to queue at pharmacies in hopes they'll find what they need.

On Telegram groups, volunteers help contact pharmacies for those who are unable to line up themselves. But with pharmacy workers already stretched thin, databases of available drugs are not always up to date. Some Ukrainians, like Dagadaeva, are struggling to find subsidized supplies, including insulin at an affordable price. They cannot afford to purchase small amounts out of pocket.

"We need to scream about it, not just talk," she said, her voice breaking. "The situation is really bad."

On a recent morning, when Tetyana Rutkis, 70, arrived at the pharmacy she runs in central Kyiv, she found no one waiting outside. When the war started, she said, "the lines stretched all the way to the park. Now there are fewer people, because there are no medicines."

With no new shipments arriving from warehouses outside of Kyiv, word has gotten around that Rutkis has to keep telling customers no.

No, she doesn't have the antibiotics this patient needs. No, the blood pressure medication another asked for has already run out. No, her last box of insulin is long gone.

"It always hurts having to say to the sick: I can't help you," she said. When she handed out her last stock of insulin, she said, she felt "powerless."

"It's upsetting," she added, her voice trailing off. "It's painful."

Three times now she has visited a branch of her pharmacy linked to a children's clinic that closed early in the war, clearing their shelves and dumping piles of medications into plastic bags she ferries to her shop across town. Many of the medications are child-size doses, but that just means she has to tell adults to take more.

Some customers, fearing stocks will run out, have bought up crucial medicines such as antibiotics, leaving those who need them urgently in limbo.

"I'm worried about everything," Rutkis said. "Every medicine can be critical. You can't be selective about it."

At another pharmacy in a major hospital in downtown Kyiv, Natasha Bolishyk, 48, has transformed a small couch in her office into her bed. In normal times, the pharmacy was open around-the-clock. Now, with roads blocked outside of the capital, most of her colleagues have fled or cannot come in to work. Her husband and son are serving in the territorial defense forces.

So for 10 days, she has not returned home, keeping the operation running for patients in need. Although a new supply was recently delivered, calming medicines and blood pressure drugs, which are in much higher than usual demand, sold out almost instantly.

"I try not to think about it because I have no idea how long I'll have to work like this," she said. "It could be a long run."

A hospital employee in line recounted that she had been looking for aspirin for three days. And her sister recently needed Augmentin - a common antibiotic that should be readily available, she said, but they couldn't find it anywhere and had to have someone ferry it across the country from the western city of Lviv.

Many Ukrainian health workers remain in the country, said Carla Melki, the emergency coordinator for Doctors Without Borders in the southern port city of Odessa. But supplies of insulin, cancer drugs and materials required for dialysis are running low in some places. And fighting has made delivering medications to front-line cities increasingly difficult.

"This is a problem of the last kilometers, where you need to bring your supply in the open conflict area," Melki said. "We know where the needs are; it's how to reach them."

Sasha Volkov, the deputy head of the International Committee of the Red Cross in Mariupol, recounted widespread shortages of food and medicines in the besieged city in an audio message shared on Twitter.

"All the shops and were looted five to four days ago," he said. "People report varying needs in medicine, especially for diabetes and cancer patients. But there is no way to find it anymore in the city."

Melki said aid and health workers in Odessa, which Russia has not yet attacked, are preparing for the "worst scenario" as Russian forces make their way through southern Ukraine. Doctors Without Borders brought in medical supplies last week to be ready in case the city becomes isolated.

The ICRC has sent nearly three tons of insulin to Odessa - enough for 6,500 people for six months - as well as enough insulin to Dnipro for 9,000 people for three months.

The Ukrainian Ministry of Health said in a statement this month that the government had delivered more than 440 tons of medicines and medical supplies worth more than $6.5 million since the start of the war. Medicines were sent to the central, eastern and southern regions of Ukraine for distribution among health-care facilities serving people in areas most affected by the fighting.

Despite efforts to keep crucial drugs in stock, civilians in cities including Kyiv are struggling to find what they need.

Oksana Avramenko, 53, bundled up in a maroon coat and green hat stood in line for hours looking for a medication she needs to treat her breast cancer. Just before the war began last month, tumors were removed from both of her breasts. But when fighting broke out, the lab handling her post-surgical test results closed down and her chemotherapy was delayed. Now she is struggling to find the prescriptions.

Nearby, Alyona Ocheretnaya, 58, waited in hopes the pharmacy would have a steroid inhaler she needs to keep her asthma under control. For the past week, she has been unable to resupply, forcing her to cut her dose in half.

"As an asthmatic, I need a higher dose because of the stress," she said after waiting in line for nearly two hours.

Even with her shelves emptying fast, Rutkis still walks several miles to and from work in winter weather each day to dole out whatever drugs she can to those in need. Even if the Russians enter Kyiv, she said, "I'll work and do whatever I can in order to help."

"And these are not just lofty words," she added. "It's something that comes from my soul."

Bolishyk, the pharmacist at a hospital in downtown Kyiv, said she hopes it won't come to that point.

"The war will end soon, not the supply," Bolishyk said. "I want to believe that."

With help from a freelance journalist working for The Washington Post in Ukraine, Dagadaeva connected to an independent volunteer helping civilians navigate wartime pharmacy access and secured doses of insulin for her son that should soon be delivered to Kyiv.

For now, that means they can stay at home in the capital. But when that supply starts to run out, the difficult search to find more will begin anew.

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O'Grady and Khudov reported from Kyiv. Parker reported from Washington.