Background A Therapeutic Equivalence Program (TEP) assembles clinically equivalent drugs and defines the best therapeutic alternative included in the hospital’s pharmacotherapeutic guide to drugs not included (DNI).

Purpose To measure the clinical and financial impact of a TEP in a tertiary hospital.

Materials and Methods Descriptive observational study conducted between November 2011 and January 2012. During the transcription and validation of the prescriptions of clinical units that work with unit-dose drug distribution system, pharmacist applied the TEP and notified the physician of the substitution in writing. The prescription of an unincluded was only retained if there was a clinical justification that made substitution impossible.

The variables collected were: rate of substitution proposals accepted and rejected, justifications for not performing the substitution, cost of the DNI, cost of the therapeutic equivalent per hospital stay and percentage of therapeutic equivalents prescribed at discharge.

Results 199 substitution proposals were sent to the physicians (51.8% accepted, 48.2% not accepted. Of these, in 17.1% of cases the patient brought the medicine from home and in 7% treatment was discontinued).

The most common clinical justification accepted (8 cases) was leg oedema caused by amlodipine (maintenance of manidipine). The second one was anaerobic infection where levofloxacin is not active (maintenance of moxifloxacin).

The global DNI price within two months of study was €1,148.78. The cost saving with the acceptance of 51.8% of substitutions was €472.63 in two months. If 100% of substitutions had been accepted, the therapeutic equivalent prescription would have saved €586.75.

In 17% of cases therapeutic equivalents were prescribed at discharge.

Conclusions The suggested substitution was accepted in more than half of cases.

The adjustment of medical prescriptions to the hospital’s pharmacotherapeutic guide prevailed over the economic saving, which was not significant.

The prescription of therapeutic equivalents at discharge was not as expected.

No conflict of interest.