The ageing population is being partly blamed for an increase in the number of people getting sick from the wrong medication

DHBs have spent more than 280-million dollars treating patients who've been prescribed the wrong drugs, over the past three years.

Otago University senior lecturer, Hamish Jamieson, says there are a lot more treatments these days, but they can cause side effects.

He says for example, doctors want to treat people's blood pressure but when they get the flu they can get dizzy, have a fall and end up in hospital.