Generic substitution raises counterfeit medicine fears, says survey

A study looking at generic substitution of medicines has found an alarming level of confusion between generic and counterfeit drugs, and raises fears that this may affect adherence to therapy.

The study, carried out by researchers at the University of Oslo, looked at the perceptions of Pakistani immigrants into Norway when their brandname medicine was substituted for a cheaper generic product by their pharmacist.

In Norway, pharmacies are required to recommend the cheapest available version when a patient presents with a prescription, and while the customer can insist on the brand, in those cases he or she must pay an extra cost to reflect the price difference. Doctors can also override the generic substitution - at no extra cost to the patient - if they believe it is necessary on medical grounds.

Using personal interviews, the Oslo researchers found that fully 25 per cent of the 83 people surveyed considered that cheaper generic drugs were counterfeit. The medications most commonly-used by those who participated in the study were for high blood pressure, diabetes and elevated cholesterol.

Two thirds had accepted generic substitution in the pharmacy whereas the remaining participants had either opposed or were unaware of the substitution. There was a trend in the results towards reduced adherence to therapy - often in the form of forgetting to take medicines or taking a drug 'holiday' - among those who had accepted a generic alternative.

Patients are reluctant to use generics in Pakistan because generic manufacturers are not required to provide bioequivalence data and there is a "significant" market for counterfeit medicines in the country, write the authors.

"This study shows that generic substitution may have a negative effect on drug adherence in Pakistani immigrants in Oslo (Norway) because of concerns and misconceptions, including confusion with regard to counterfeit drugs," they conclude.

The results have been published in the European Journal of Clinical Pharmacology (Open access PDF available ahead of print here).