Background Drug dosage modifications are a common clinical practise regarding Tumor Necrosis Factor (TNF) blockers, using posologies not specified on the authorised product information summary. This practise has a significant financial impact on the healthcare system.

Purpose To revise and investigate actual drug dosages in our Hospital’s rheumatology service for conventional TNF blockers.

Materials and Methods The Pharmacy Service analysed the internal data record for rheumatology patients treated during April 2012 and for at least one year with infliximab (IFX), etanercept (ETN) or adalimumab (ADA). Off-label indications were excluded. Therapeutic indication, initial and current posology were recorded.

Results Number of patients by drug;

Number of patients by indication:

RA: Rheumatoid arthritis, AS Ankylosing spondylitis, PA psoriatic arthritis, JIA: Juvenile idiopathic arthritis

Regarding posology, 261 patients (65%) were on a conventional dose (CD), 93 (23%) on a reduced dose (DR) and 47 (12%) on an increased dose (DI)

Percentage of patients by drug on CD, DR or DI was;

Percentage of patients by indication was;

Conclusions Only 65% of patients using TNF blockers on rheumatology use a CD while a quarter of them have a reduced posology.

Infliximab is the drug that requires more dosage modifications, on almost 2/3 of patients.

AS and PA are the indications that allow more DR.

Drug dosage revisions at the end of the first year of treatment allow an important number of patients to reduce their dose while controlling their disease and it is a relevant efficacy instrument.

No conflict of interest.