Clinical pharmacy services aim to enhance patient outcomes and reduce the risk of potential drug-related harm by offering patient-centred pharmaceutical care. In the hospital setting, clinical pharmacists collaborate with physicians as part of a multidisciplinary team to identify and prevent DRPs (Drug-related problems). Clinical pharmacist interventions encompass 'any action initiated by a pharmacist that directly results in patient management or a modification in medication.' The favourable clinical and economic impacts of interventions have been well-established for decades. Clinical pharmacists have played an important role in ensuring the effective and correct use of medicines in many settings.

This study aims to investigate the clinical pharmacy services provided by clinical pharmacists to patients receiving antithrombotic therapy. For this study, patients were divided into two groups: a control group and an intervention group. A comprehensive medication review will be conducted by the clinical pharmacist for both the control and intervention groups. Drug-related problems such as drug selection, dose errors, possible drug-drug interactions, and inappropriate drug use, will be identified. In the control group, no interventions will be made by the clinical pharmacist. In the intervention group, solution recommendations for identified and clinically significant issues will be presented to the physician, and the provided services will be documented. Furthermore, the groups will be evaluated for whether there are any hospital readmissions within 1 and 3 months following discharge for the patients.

Patients with cardiovascular disease are at significant risk for adverse drug events and medication errors. Moreover, the rate of use of high-risk drugs such as antithrombotic drugs is higher in these patients. In the literature, antithrombotics have been shown as one of the main causes of adverse drug events and drug-related hospitalizations. Therefore, follow-up of patients treated with antithrombotics is very important. Guideline-based therapy significantly reduces the risk of all-cause and cardiovascular (CV) death. Multidisciplinary antithrombotic management can play an important role in increasing prescribing physicians' adherence to guidelines. Effective interventions such as medication review, establishment of treatment protocols, education, and medication reconciliation at hospitalization and discharge can help increase adherence to the guideline. In patients receiving antithrombotic therapy, individual evaluation of drug therapy suitability, formulation of a drug treatment plan, dose adjustment, drug monitoring, detection and prevention of clinically important drug-drug interactions, and antithrombotic transition protocols should be considered. Such interventions must appropriately balance each individual's risk of thromboss and bleeding.

Pharmacists are recognized as leading healthcare professionals in detecting, resolving, and preventing DRPs. Assessments of the quality and value of pharmacist interventions remain crucial for the development of new pharmaceutical care services and for enhancing our understanding of the frequency and variety of DRPs observed in various clinical settings. The literature has demonstrated the impact of Clinical Pharmacy Services on cardiovascular patients. Collaborating with a clinical pharmacist during inpatient treatment has been shown to improve medication adherence, reduce adverse drug reactions, and minimize medication errors post-discharge. The benefits of these pharmacist-led services in reducing hospitalization and healthcare costs were emphasized. Clinical pharmacy services have contributed to an enhancement in healthcare quality without compromising patient well-being. Pharmacists can take on the responsibility of antithrombotic management, ensuring that patients receive the right medication, in the correct dosage, and for the appropriate duration from the initial consultation to outpatient follow-up. Increasing the continuity of pharmaceutical care will enhance patient outcomes and reduce costs.

In this study, two groups were established as control group and intervention group. In the control group, no interventions will be made by the Clinical Pharmacist. Within the intervention group, patient characteristics such as the length of hospital stay, reason for hospitalization, underlying conditions, and the appropriateness of prescribed medications were evaluated for the patients who received antithrombotic treatment and met the inclusion criteria. Through medication reviews, evaluations were made to identify drug-related problems and provide solutions to these problems. The clinical pharmacist provided recommendations to the physicians regarding significant clinically important problems. Additionally, follow-up was performed to determine whether the patients had a re-admission within 3 months.

Inclusion Criteria:

• Being 18 years and older.
• Receiving antithrombotic treatment.
• Having complete biochemical and complete blood count values collected at least twice, with two-day medication information fully entered into the hospital system.
• Patients who could be evaluated by the clinical pharmacist for at least 24 hours within the intervention group.

Exclusion Criteria:

• Being under 18 years old.
• Not using antithrombotic medication.
• Patients whose biochemical and complete blood count values were not collected twice and whose two-day medication information was not fully recorded in the hospital system.
• Patients in the intervention group whom the clinical pharmacist did not see for at least 24 hours (weekend hospital admission followed by Monday morning discharge, Friday admission with weekend discharge, etc.) were excluded from the study.