The topic of generic drugs came up recently in a meeting with the International Glaucoma Association. In general, I have nothing against cheaper formulations of drugs being made available as long as they work and don’t cause any problems. There are some issues, however.

i) The vehicle in which the drug is delivered could change. ie a different preservative, preservative concentration, background solution composition, acidity. These could potentially cause local allergy problems

ii) The drug it self might not be quite the same compound and be less effective.

iii) The bottle itself may be different. This can make it difficult for patients to instill the drops (see attached video)

iv) The bottle plastic might interact with the drug.

Usually, these are not serious enough to cause problems. But often patients are giving different generic drugs with each prescription and we don’t know whether they are effective until the eye pressure is measured in the clinic. Consistency is the key. If you are given a generic drug, it should be fine, but the formulation mustn’t change with each precription.