Polypharmacy and Potential Drug-Drug Interactions in Patients with Psoriatic Arthritis

Abstract

Background: Psoriatic arthritis (PsA) is an inflammatory arthropathy linked to psoriasis and typically negative for rheumatoid factor. Patients with PsA are at a higher risk of polypharmacy due to comorbidities and widespread pain. This growing health problem leads to negative outcomes like increased mortality, falls, medication adverse effects, prolonged hospital stays, and re-admission after discharge.

Objectives: Assessment of polypharmacy in patients with PsA, its relation to patient characteristics, and the potential for undesirable interactions between drugs used to treat PsA and those used for other conditions.

Methods: A cross-sectional study was conducted at the Rheumatology Unit of Baghdad Teaching Hospital/Medical City Complex, during the period from January 2023 to January 2024. The study included 100 adult PsA patients diagnosed according to the Classification of Psoriatic ARthritis (CASPAR) criteria. The demographic and disease-related characteristics were collected using a pre-constructed data collection document. Polypharmacy was defined as the concurrent use of at least five drugs irrespective of their duration. The drug interaction checker® of Medscape’s database was used to assess the drug-drug interactions.

Results: Sixty-three of the 100 PsA (63%) patients exhibited polypharmacy, and there were 236 potential drug-drug interactions. The majority of these interactions were due to the use of methotrexate with folic acid, NSAIDs, and PPIs. Drug interactions were less frequent with the tumor necrosis factor (TNF) inhibitor.

Conclusion: The prevalence of polypharmacy was elevated among PsA patients. Polypharmacy was significantly correlated with patient age, peripheral disease activity, and the existence of comorbidity. Polypharmacy was linked to an increased risk of possible drug-drug interactions.