Background and importance Oral vancomycin (125 mg four times daily) is the standard treatment for mild/moderate Clostridium difficile infection (CDI). As there are no marketed vancomycin capsules in our country, vancomycin 500 mg vials have been taken orally for this purpose. But high price, difficult acquisition and complicated dilution and administration, especially among elderly patients, were associated with poor adherence to treatment and a higher risk of recurrence.

Aim and objectives To study the clinical effectiveness of oral vancomycin in patients with CDI and to compare the utilisation of two different pharmaceutical forms: vials and capsules.

Material and methods A retrospective, observational, cohort study was conducted. Vancomycin 125 mg capsules were first compounded and dispensed by us in January 2018. Electronic health records of outpatients with an episode of CDI and receiving vancomycin vials (January 2017 to December 2017) or capsules (January 2018 to December 2018) were reviewed. Variables analysed were: demographics (sex, age), CDI episode (new episode, first recurrence, second or subsequent recurrence), vancomycin pharmaceutical form, treatment adequacy (dosing and duration, as recommended from clinical guidelines), recurrence rate (presence of symptoms within 60 days of treatment), treatment adverse effects and hypervirulent PCR-ribotype 027 strain cases (epidemiological and clinical interest).

Results 99 patients were included, 35 receiving vancomycin vials and 64 receiving compounded vancomycin capsules. Demographic characteristics were similar between groups (median age was 60 years; 59.6% women).

Vials cohort: 22 diagnoses of a new episode (62.8%), 11 first recurrences (31.4%) and 2 second or more recurrences (5.8%). Capsules cohort: 48 diagnoses of a new episode (55%), 13 first recurrences (20.3%) and 3 second or more recurrences (4.7%). Recurrence occurred within 60 days in 13 (37%) of the patients from the vial cohort and in 20 (31%) patients from the capsules cohort (p=0.52). Inappropriate oral vancomycin dosing decreased from 28.6% (vials) to 6.3% (capsules) (p=0.002). No vancomycin adverse effects were reported. PCR-ribotype 027 was found in 9 patients (9.1%).

Conclusion and relevance Oral vancomycin is safe regardless of the pharmaceutical form. Prescription adequacy improved with capsules. Further studies need to be done to confirm if dispensing capsules containing an appropriate drug dose relates to less recurrence rate, and better adherence and outpatient satisfaction.

Conflict of interest No conflict of interest