Scotland's methadone programme now costs more than £15m a year, according to the latest official statistics.
The ISD Scotland figures represent a rise of 25% over the past five years.
Methadone prescribing rates rose by 9% in the same period, despite the new strategy to concentrate on recovery from addiction rather than maintenance.
The report also revealed a total of 10,325 people entered drug treatment services in 2009-10, with two-thirds of those using heroin.
Drug injecting remains a problem, with 28% of heroin users taking the drug intravenously in the month before they sought treatment.
The average daily spend on drugs for those entering treatment in the past year was £43. Heroin users spent on average £33, while cocaine users spent on average £108 a day.
But the number of cocaine users entering treatment has dropped, from more than 1,200 in 2008-09, to about 750 in 2009-10.
The number of crack cocaine users who entered treatment in the past year has also nearly halved, compared with 2008-09 - although the vast majority of users - 47% - continue to be concentrated in the Grampian health board area.
The Information and Statistics Division has also just released a report on drug treatment waiting times, which reveals that those seeking treatment have been assessed and treated quicker, with three-quarters getting an appointment within a fortnight of referral.
The Scottish government said the increase in the money spent on the methadone programme was down to increased costs rather than a corresponding rise in the number of users.
The most recent count of methadone users was carried out by the Scottish government in 2007, when about 21,000 people were said to be using the drug to help them get off heroin.
Currently, statisticians only collate the number of prescriptions issued - 510,063 in 2009-10 - which represents about 98 per 1,000 population, an increase on 90 per 1,000 population in 2005-06.
Communities Minister Fergus Ewing said progress was being made, but tackling Scotland's drug problem will not happen overnight.
"We all know Scotland has a historical and very distressing problem with drug abuse, which this government is absolutely committed to tackling," he said.
"However, I am convinced we are following a path that will get people off drugs and into recovery.
"Since 2008, we have invested a record £81m in local drug treatment services to enable them to help make that possible."
A spokeswoman for Scottish Drugs Forum, the national drug policy and information charity, said: "Published figures show that methadone costs in Scotland dropped by nearly £800,000 last year from the previous year - down from £16,072,828 in 2008/2009 to £15,296,744 in 2009/2010, a drop of £776,084.
"This is the first drop in costs since 2005/2006, so it's unhelpful to ignore this by concentrating only on the five year spending trend.
"Methadone is internationally recognised as an effective treatment to allow people to move away from high-risk illicit drug use."