ObjectiveTo determine the impact of medication therapy management interventions on drug therapy problems (DTPs), medication adherence and treatment satisfaction among ambulatory heart failure (HF) patients.Study design, setting and participantsA one-group pre–post quasi-experimental study was conducted on 423 ambulatory HF patients at Tikur Anbessa Specialised Hospital (TASH), Addis Ababa, Ethiopia. All ambulatory HF patients ≥18 years old attending the adult cardiac clinic of TASH and having a complete medical record and fully met the inclusion criteria were taken as study participants.InterventionsEducational interventions along with a brochure with information on the nature of HF disease and its treatment were provided to study participants. DTPs encountered were resolved by a team of pharmacists and physicians.ResultsIn the preintervention phase, 288 DTPs were identified with a mean (SD) of 1.3±1.1. A significant reduction of DTPs (0.67±1.1, p<0.001) was observed in the postintervention phase compared with the preintervention phase. At the postintervention phase, 36.4%, 61.9% and 1.7% of HF patients were highly, medium and low adherent to their treatment regimens, respectively. The total composite score for treatment satisfaction of the study participants was 80.35%.ConclusionsThe findings of this study demonstrated that by teaming up clinical pharmacists with cardiologists and cardiology fellows, it was possible to reduce the occurrence of DTPs, improve medication adherence and increase treatment satisfaction of HF patients attending at the outpatient cardiac clinic.