A 700% spike in the price of a drug used to wean addicts off heroin has caused alarm among treatment agencies, which warn of a rise in drug-related deaths unless urgent action is taken to make it more affordable.

Buprenorphine is an alternative to methadone that reduces the symptoms of withdrawal and lessens the desire to use heroin. It is estimated that more than 30,000 people in England use the drug, which offers a reduced risk of overdose compared with methadone.

Earlier this year it emerged that one of the makers of the generic drug, which is far cheaper than its branded equivalent, Subutex, had stopped producing it. Amid fears of an impending shortage, the government stated that pharmacies could be paid close to the same price for dispensing buprenorphine as Subutex, in an attempt to encourage manufacturers, who could command higher prices elsewhere, to continue supplying the UK. Prices rocketed.

A month’s supply of buprenorphine had typically cost about £16. After the hike it was £130. A clinic run by the rehabilitation charity Addaction saw the price it was paying for of the drug rise by 745%. Another local service saw its monthly buprenorphine bill soar from £11,058 to £55,543 in four months.

Turning Point, a drug treatment charity, said the impact of the price hike since May was equivalent to the annual budget of an entire local authority drug and alcohol treatment service. It said providers of substance misuse treatment were now having to work out whether they could afford to prescribe buprenorphine. It warned that any move to switch recovering addicts from buprenorphine could result in disengagement in treatment and increases in drug-related deaths.

“Over the past six months we have seen prices rise by up to 700% as a result of shortages of buprenorphine,” said Lord Adebowale, chief executive of Turning Point. “Questions have to be asked as to whether this is sustainable in a sector already feeling the impact of budgets cut by 25% in five years. Urgent action is needed as it impacts some of the most vulnerable people in society.”

The price rise threatens to jeopardise already limited progress in curbing heroin-related deaths. In 2017, 1,164 people died from heroin and morphine misuse, a 4% decline and the first drop since 2012.

Questions are being asked about whether the supply of the drug is being restricted.

The shadow health secretary, Jonathan Ashworth, questioned the role of the drug makers in the crisis. “We already have record deaths from drug misuse, while treatment services have been slashed by millions in recent years,” he said. “Yet again, this looks like ‘big pharma’ exploiting the market by ramping up the price, and some of the most vulnerable in society ultimately paying a devastating price. With treatment services on the brink, these escalating costs could push many into absolute crisis. Ministers urgently need to step in, get a grip and ensure access to this vital drug for the most vulnerable at fair prices.”

It is understood that Public Health England had been asked to look at providing additional funding but has been told there is no money available.

A Department of Health and Social Care spokesperson said: “There were some very short-term supply issues with generic buprenorphine in May, but these were resolved quite quickly.”

However, the DHSC’s own data confirms that a box of 8mgbuprenorphine tablets currently costs £15.74, the second-highest price it has commanded in six months. It cost about £1.80 before the rise.

Three manufacturers of buprenorphine – Sun, Morningside and Sandoz – were approached for comment. Sun did not return calls. Morningside declined to comment. Sandoz referred the Observer to the British Generic Manufacturers Association, whose director-general, Warwick Smith, said historically low prices for buprenorphine since 2012 had seen some suppliers leave the market.

“Price increases of this type attract other companies to supply, which resets the price at a lower but more sustainable level,” Smith said.

But Mike Dixon of Addaction said people could not wait for prices to fall. “Buprenorphine is a lifesaver for thousands of people. We should not be in a situation where this kind of generic medicine is subject to supply problems. It heaps anxiety on people who are doing everything they can to get better.”