Consumer perceptions of digital pharmaceutical marketing and OTC medicine purchase behaviour: evidence from an Indian metropolitan city

Purpose The growing use of digital platforms by pharmaceutical firms has fundamentally reshaped how consumers engage with over-the-counter (OTC) medicine information. This study aims to investigate how consumer perceptions of digital pharmaceutical marketing – specifically perceived informativeness, credibility and intrusiveness – shape OTC medicine purchase intention and self-reported purchase behaviour within an emerging market context. Design/methodology/approach Primary data were gathered through a structured survey of 412 consumers residing in Kolkata who had demonstrable prior exposure to digital pharmaceutical marketing. Established measurement scales were used to operationalise key perceptual constructs. A two-stage analytical framework was adopted: the first stage tested perceived informativeness, credibility and intrusiveness as antecedents of purchase intention (including moderation analysis); the second stage examined the pathways through which purchase intention and credibility jointly determine purchase behaviour. Findings Perceived informativeness and credibility each exert a significant positive influence on purchase intention, while perceived intrusiveness diminishes it. Purchase intention subsequently predicts purchase behaviour and credibility demonstrates an additional direct effect on behaviour beyond this intentional pathway – confirming a dual-path trust mechanism. Moderation analysis reveals that intrusiveness does not significantly condition the effects of either informativeness or credibility on intention; instead, it functions as an independent structural deterrent. Research limitations/implications The study is subject to certain limitations. It adopts a cross-sectional design, which restricts causal interpretation of the observed relationships. Purchase behaviour was measured using self-reported responses, which may be influenced by recall bias. In addition, the research focuses on consumers from a single metropolitan city, which may limit generalisability to rural or semi-urban contexts. Future research could use longitudinal or experimental designs, explore diverse geographic settings and examine emerging digital formats such as influencer-based health communication. Practical implications The findings underscore the primacy of credibility-driven communication in digital pharmaceutical marketing. Firms should prioritise transparency, evidence-based messaging and minimal intrusiveness to sustain consumer trust and convert digital engagement into actual purchase decisions. Segment-specific strategies – particularly for younger, digitally active consumers – are recommended. Social implications Digital pharmaceutical marketing increasingly shapes how consumers make self-medication decisions. The findings highlight the social importance of responsible and transparent digital communication in the pharmaceutical sector, particularly for OTC medicines where professional guidance may be limited. Emphasising credibility and avoiding intrusive promotional practices can help protect consumer trust and support informed health-related decision-making. The study underscores the need for ethical standards in digital pharmaceutical marketing to safeguard consumer well-being while promoting access to reliable medicine-related information. Originality/value This study advances the digital pharmaceutical marketing literature by proposing and empirically validating a two-stage information–trust–behaviour framework applicable to OTC medicine contexts in emerging markets. By isolating the direct behavioural role of credibility from its intentional pathway, the study offers a theoretically refined account of how trust operates in health-related digital decision-making environments characterised by information asymmetry and limited professional mediation.