The Tories have campaigned strongly against methadone treatment
Urgent action needs to be taken over the "escalating" use of the heroin substitute methadone to treat addicts, it has been warned.
The Scottish Tories said the country was "over-dependant" on methadone.
Leader Annabel Goldie has written to First Minister Alex Salmond claiming annual costs had risen 19% from £21.5m last year, to £25.7m in recent figures.
The Scottish Government said its aim was to provide the right support, without promoting one treatment.
Ms Goldie welcomed the government's national drug strategy, which recognises recovery and abstinence.
"However, as these figures clearly demonstrate, the problem is escalating, not diminishing," Ms Goldie outlined in her letter.
"It is all too evident that we have become over-dependent on methadone as a treatment and when we still have addicts waiting for over two years to get other forms of rehabilitation, the scale of the problem becomes clear.
"It is urgent that we move from the aspiration of a new approach, as outlined in the new national drugs strategy, to real action."
Ms Goldie asked the first minister if any guidelines had been issued to regional drug and alcohol action teams following the "welcome change of political direction".
She continued: "We all know that the success of a new national drugs strategy is a long-term ask, one which will take years to become fully successful.
COST OF METHADONE DISPENSING 2007-08
Ayrshire and Arran: £2,218,779
Dumfries and Galloway: £609,197
Forth Valley: £990,629
Greater Glasgow and Clyde: £11,588,654
Western Isles: £48
Source: Parliamentary answer
"But in the short-term, progress must be made and the figures I mention today suggest that this is regrettably not the case."
The government said costs could vary over time and methadone costs rose by nearly 30% between April 2007 and April 2008.
Community Safety Minister Fergus Ewing added: "The drugs strategy recognises the need to help people move on from methadone through other treatments.
"Different people with different circumstances inevitably means different routes to recovery.
"The challenge is to make sure that the right support is available at the time it is needed, rather than promoting one particular type of treatment."
This year's figures were revealed in a parliamentary answer by Health Minister Shona Robison on Wednesday.
The biggest bill run up by community pharmacies across Scotland's health boards was in Greater Glasgow and Clyde, where it cost £11.588m.
The next highest bill, £3.663m, was in Lothian, while the third highest, £2.218m was in Ayrshire and Arran, followed by £2.1m in Grampian.