Crimea's annexation by Russia is set to bring far-reaching changes to its 2.3 million inhabitants.
Perhaps no Crimeans will feel these changes more keenly than the 800 heroin addicts currently undergoing methadone treatment on the peninsula.
On March 26, less than a week after formally completing its annexation, Russia announced it was banning the substitution drug in Crimea -- a devastating blow to drug users who had pinned their hopes on methadone to break free from addiction.
"The vast majority of them will revert to illegal drugs," predicts Maksim Malyshev, who runs a group lobbying for less stringent drug policies in Russia. "Even in Russia, local drug addicts have no access to free, comprehensive, quality rehabilitation treatment."
Russian authorities have ordered all methadone distribution centers in Crimea to shut down by April 30.
But with highways connecting Crimea to mainland Ukraine blocked for weeks, health workers say methadone supplies are unlikely to last until the end of April anyway.
"We've been forced to reduce the dosages. The conditions of patients are already degrading," Ihor Kuzmenko, a methadone center employee in Simferopol, tells RFE/RL. "Our stocks of drugs, which were already catastrophically low, are rapidly dwindling."
In addition to weaning addicts off heroin by blocking the pain of withdrawal, Crimea's methadone clinics also offer psychological counseling and medical treatment for a range of diseases.
Experts warn that the discontinuation of these services will sound the death knell for many substance users in Crimea, usually too marginalized to seek help from mainstream services.
"Most of these people have HIV and hepatitis C, about 100 of them probably have tuberculosis," says Malyshev. "They are doomed to die."
One methadone user in Sevastopol, Sergei Kislov, told The Associated Press that the Russian ban amounted to "a massacre."
Kislov, who voted for his region to join Russia, accused Moscow of "abandoning" Crimea's recovering addicts and "forcing them to fend for themselves, even if that means we'll end up stealing again and going to jail."
To avoid withdrawal and a possible relapse, Crimean rehab patients are now left with two options: relocate to mainland Ukraine to continue their methadone therapy or quit cold turkey in a Russia-run facility.
Crimea's new de facto authorities have already offered to send methadone patients to Russia for detoxification and rehabilitation treatment.
And in at least one city, St. Petersburg, health officials have caught on to the idea.
Their proposal to book 100 Crimean patients into St. Petersburg's Narcological Hospital, however, has met with little enthusiasm from local health workers.
"There are a number of difficulties with this proposal," says Viktor Grigoryev, a doctor at the St. Petersburg clinic. "With our capacities, we can only take in 20-25 of these people."
The methadone ban in Crimea has also sparked fears that more drug users will return to sharing dirty needles, undermining Ukraine's advances in curbing HIV on the peninsula.
Ukraine has spearheaded regional efforts to introduce substitution therapy and needle exchange programs, two measures seen as effective in preventing HIV among drug users.
According to the International HIV/AIDS Alliance of Ukraine, drug injectors accounted for 33 percent of new HIV infections in the country last year, down from 62 percent in 2002.
Russia, which rejects both methods, has one of the fastest-spreading HIV/AIDS epidemics in the world.
Last year alone, it recorded a 7-percent leap in new cases. Needle sharing was the primary cause of infection.
Written by Claire Bigg in Prague based on reporting by Viktor Rezunkov in St. Petersburg.