Spending on GP prescribing has fallen by 11% over the past seven years, despite the number of prescriptions increasing by a third, a report has revealed.
The fall in real terms spending since 2004/05, to £974 million in 2011/12, has been attributed to improvements in how the NHS manages prescribing in general practice, Audit Scotland said.
But the watchdog reported room for improvement, estimating that a further £26 million a year could be saved without affecting patient care.
Auditor General for Scotland Caroline Gardner said: "Most people in Scotland get a prescription from their family doctor at some point to treat or prevent an illness or help sustain a good quality of life.
"The NHS spends almost £1 billion a year on drugs prescribed in general practice.
"Since we last looked at GP prescribing, the volume of drugs prescribed has continued to rise but the NHS has significantly improved how it manages spending.
"This was during a period when there have been considerable pressures and constraints on the health service."
She added: "It has achieved this through providing doctors with more support and guidance, and using better information about what GPs are prescribing."
The report said that the quantity of drugs prescribed since 2004/05 had risen by 33%, with around 91 million prescriptions issued in 2011/12. The biggest factors affecting prescribing are patient age and levels of deprivation.
More than 900,000 people in Scotland over the age of 50 are taking four or more different drugs while GP practices serving the most deprived areas prescribe on average 46% more drugs per head of population than those in the least deprived areas.