Carolyn Bird was desperate for help with her chronic pain when her physiotherapist suggested she try Mt Nelson Medical Centre.
Since 2015, the Hobart clinic has been researching the use of a topical medication to treat complex regional pain syndrome.
"I was a little bit nervous to be honest because it sounded like an unusual project to get involved in, but I'm really glad I did because it's made such a huge difference," Ms Bird said.
But Ms Bird said her outlook was "bleak" as she faces a future without access to the spray.
"I have pretty much run out of the medication and because it's not available I'm actually getting worse again and spending a lot more time in bed and having to lay down at work," she said.
About six weeks ago, Mt Nelson Medical Centre was raided by Tasmania Police after a tip-off by Pharmaceutical Services.
Medication, computers and medical records have been confiscated, leaving general practitioner Clive Stack unable to contact his patients, many of whom are vulnerable.
"The warrant said they were investigating ... manufacture of a controlled substance, which as we understand it ... is an indictable offence that requires you be selling drugs or manufacturing an illicit drug or selling it, which we're obviously not," Dr Stack said.
While police are yet to lay charges, Dr Stack said he suspected an administrative error had led to the raid.
"We needed some [pain medication] for a patient because we were running out so ordered the constituent ingredients," he said.
"Normally that process is done through our research team and there's a certain process they have to follow.
Police and the Pharmaceutical Services Branch declined to comment when contacted by the ABC.
Shutting down the clinic like 'going backwards'
Dr Stack, who runs Mt Nelson Medical Centre through his registered charity Humanitas, emphasised he had no issue with Tasmania Police or Pharmaceutical Services.
But he has been forced to put the practice on the market to help fund a potential legal case and has started to wind down the charity because it is effectively unable to operate.
Another former patient of Dr Stack's, Louise Richardson-Self, said the clinic's pain treatment had changed her life and she hoped Tasmania Police acted quickly so the issue could be sorted out.
"I can't, in good faith, knowing how much this has helped me, stand by and say nothing when the potential is there that there are women who will never have the opportunity to have the same treatment," Dr Richardson-Self said.
Steve Ryan, who also has complex pain, said he believed the potential closure of the clinic was "cruel".
"To have it shut down is like going backwards, like going back 10 years or five years where there wasn't this sort of thing to help," he said.
Dr Stack said his decades of working with drug and alcohol patients meant he was particularly careful when developing his topical pain treatment.
"So we've done everything we can not just to make our medication safe, but also to try and find a way to treat pain that doesn't involve an addictive agent."
Dr Stack also said he was troubled that patient records were not treated as "in confidence" and were able to be seized by police.
A Tasmania Police spokeswoman said: "Any electronic device seized by Tasmania Police has strict security arrangements in place. Once an item is examined, it is either held for court purposes or returned to the owner."
