Trimethoprim–Sulfamethoxazole: new lessons on an old antimicrobial; a retrospective analysis

Abstract Objective This study aimed to evaluate the appropriateness of TMP-SMX prescriptions as part of drug utilization review. Method Charts of all patients (adults and paediatrics) admitted to Hamad General Hospital who received TMP-SMX from December 2016 till May 2017 were reviewed and assessed for prescribing/administering appropriateness. Key findings Total of 149 patients was included (55 paediatrics, 94 adults). None of the adults were tested for G6PD before initiating TMP-SMX, while most of the paediatrics (85.5%) had a record of G6PD status. Dosing of TMP-SMX was considered appropriate in 65% of the paediatrics, whereas only in 49% of adults. Bone infections and S. maltophilia were the uppermost indications associated with inappropriate dosing (85.7 and 74.3%, respectively). Errors in dosing were observed to be higher with intravenous formulations (51.2%) compared to orals (35.2%). With regard to pharmacy verification/dispensing, 135 out of 149 orders (90.6%) were correctly verified/dispensed. Appropriateness of the prescribed dosing was only significantly affected by the indication for TMP-SMX use (P-value < 0.001), while the route of administration was the only variable that correlated significantly with pharmacy verification/dispensing errors (P-value 0.032). Conclusion TMP-SMX prescribing patterns were not always optimum. The results of this study should promote healthcare facilities to review/ensure optimal utilization of TMP-SMX which can consequently help in diminishing burden of antimicrobial resistance.