Collaborative Practice in Oral Nutritional Supplement Provision: The Critical Role of Pharmacists in the Patient Journey

Background/Objectives: Disease-related malnutrition affects millions of patients worldwide. Nutrition support therapy (NST), namely oral nutritional supplements (ONSs), serve as a cornerstone therapeutic intervention. However, treatment effectiveness depends not only on an appropriate prescription but also on patient acceptance and adherence. This study evaluates the provision pathway of ONSs within a co-payment healthcare system, focusing on patient acceptance patterns, barriers to adherence, and the critical yet underexplored role of pharmacist–patient interactions in determining treatment outcomes. Methods: A cross-sectional observational study was conducted across 100 Croatian community pharmacies during September–October 2025. Pharmacists prospectively documented 973 patient encounters involving ONS prescriptions requiring co-payment using real-time patient record forms. Data captured patient demographics, diagnoses, prescription patterns, prior knowledge of co-payment requirements, acceptance responses, and pharmacist-assessed reasons for refusal. Results: While 65% of all patients knew about co-payment requirements in advance, 51% of first-time users arrived uninformed, leading to dramatically different acceptance patterns (93% immediate acceptance when informed versus 33% when uninformed, p < 0.05). Overall, 8–12% of patients refused or reduced prescribed ONSs. Among refusals, 59% cited the financial burden, but, critically, 23% appeared not to understand why an ONS was prescribed or what benefits to expect, revealing significant communication gaps in the care pathway. Overall, fifteen percent of patients required an explanation from the pharmacist before accepting their prescription, demonstrating pharmacists’ decisive role as gatekeepers of nutritional therapy. Conclusions: These findings suggest that the pharmacy dispensing encounter is an important decision point in the ONS care pathway, where insufficient preparation and coordination may be associated with suboptimal treatment outcomes among vulnerable patient populations. Improved prescriber–patient communication about co-payment and clinical rationale, pharmacist education in disease-specific nutrition and ONS counseling, and structured communication protocols between prescribers and pharmacists represent areas that may warrant further attention and evaluation.