The mediating role of drug knowledge in consumer purchase intentions for over-the-counter drugs

Purpose This study explores the impact of psychological and informational factors, including attitudes, subjective norms (SN), perceived behavioral control (PBC), product awareness (PA) and drug knowledge (DK), on consumer intentions to purchase over-the-counter (OTC) drugs. The study uses the theory of planned behavior (TPB) as the theoretical framework, while also considering the mediating role of DK. Design/methodology/approach A cross-sectional survey was conducted with 627 participants from the North Gujarat region, including urban, semi-urban and rural areas. Data were collected using a structured questionnaire measuring the five key factors and the intention to purchase OTC drugs. Structural equation modeling (SEM) was used to analyze the direct and indirect effects of these factors on purchase intentions. Findings The findings show that all five factors significantly influence purchase intentions, with attitude toward OTC drugs having the most substantial impact, followed by PA and DK. SN and PBC also positively contributed, but to a lesser extent. DK was found to mediate the relationship between psychological factors and purchase intentions, highlighting its central role in the decision-making process. Originality/value This study extends the TPB in the context of OTC drug purchasing by integrating PA and DK with the traditional TPB constructs of attitude, SN and PBC. Its principal contribution lies in examining DK not only as a direct predictor of purchase intention but also as a mediating mechanism through which psychological and informational factors influence consumers’ intentions to purchase OTC drugs. By empirically testing these relationships among consumers from urban, semi-urban and rural areas of North Gujarat, the study provides a more integrated explanation of OTC purchase intentions and contributes to the relatively limited literature connecting behavioral and informational determinants in self-medication decision-making.