[Prescription, dispensation and sustitution of prescription forms of omeprazole].

OBJECTIVE: To verify and quantify, for a given active principle (omeprazole 20 mg) and for selected primary care physicians and pharmacies, the extent to which the drug prescribed on official national health system prescription forms coincides with the drug dispensed or whether the drug was dispensed following the pharmacist's criteria because the prescription was drafted in terms of the official Spanish denomination (OSD). In either case, the cost of the prescription is expressed in terms of the defined daily dose (DDD).

METHOD: We reviewed 592 public health service prescriptions for omeprazole 20 mg, prescribed by 56 primary care physicians with a high prescription rate for this active principle, which were dispensed in 16 pharmacies.

RESULTS: Prescriptions dispensed according to the physician's prescription (50% of the prescriptions) were cheaper than those expressed in OSD and dispensed as generic drugs by pharmacists using their own criteria (36% of the cases). In all cases of substitution of the prescribed drugs (14% of prescriptions), a generic drug was dispensed and 76% of these were more expensive than the prescribed drug.

CONCLUSIONS: The results show that primary care physicians tend to take into account the cost of the drug and to choose cheaper drugs even when these are not generic. When pharmacists substitute the prescribed drug, they tend to dispense a generic drug that is more expensive.