The most vulnerable are among the 40 per cent of people still paying for prescription medicine when they should be exempt, a university study has found.
After paying for 20 prescription items in a year, individuals and families should be excluded from paying for further medicine, said the University of Otago and Victoria University.
But the research team found 40 per cent of people still paid for 90 per cent of their next prescriptions.
To receive the exemption, people must have a Prescription Subsidy Card, have one main pharmacy, and collect receipts from any other pharmacies they visit and take these to their main pharmacy.
However, many people might not know about the card or procedures, said Professor Pauline Norris.
Researchers found the results using anonymous data from community pharmacy computers which identified individuals who had had more than 20 items dispensed to them in a year.
Most of them were from the country's most socio-economically deprived areas.
"Those with multiple health problems, the elderly and people with low health literacy ... might struggle with these procedures required to be exempt," said Professor Norris.
The cost to patients buying prescriptions when they should be exempt was about $2.5 million a year, said the study.
Standard charges for prescription medicines will go up from $3 to $5 in January.
New Zealand and overseas research has shown prescription charges lead to less use of medicines and poorer health outcomes, said the researchers.
