Belief and bioavailability: a pharmacokinetically-driven analysis of Islamic fasting fatwas and its implications for clinical counselling

<title>Abstract</title> <p>Background. Each Ramadan, over a billion Muslims fast from dawn to sunset, and many with chronic illness autonomously alter or discontinue their medication to preserve the validity of their fast — a decision with direct consequences for patient safety and health equity. These decisions rest on religious rulings (fatwas) that classify which routes of drug administration break the fast, rulings grounded in a classical anatomical framework centred on substance entering the body cavity (Jawf) through an open orifice. Whether that framework tracks the morally and physiologically relevant features of modern drug delivery — and what follows for clinicians counselling fasting patients — has received little scrutiny. Methods. The primary fatwas and consensus resolutions of three major contemporary Islamic jurisprudential bodies — the International Islamic Fiqh Academy, Dar al-Iftaa al-Misriyyah (Egypt), and the General Iftaa Department of Jordan — supplemented by a preliminary examination of the Saudi Permanent Committee were retrieved and analysed. These rulings were evaluated against an established pharmacokinetic framework grounded in the two-compartment model and systemic bioavailability. Results. Several rulings cohere with pharmacokinetic evidence, including the permissibility of transdermal and non-nutritive parenteral preparations. However, substantive inconsistencies emerged: the divergent treatment of metered-dose inhalers, dry powder inhalers, and nebulizers despite shared local action; contradictory rulings on rectal suppositories and sublingual tablets; and an internal contradiction in ophthalmic versus nasal rulings that overlooks their shared nasolacrimal drainage. In several cases, a permitted route delivers greater systemic drug exposure than a prohibited one. Conclusions. Where fast-invalidation rulings rest on empirical premises about anatomy and drug movement that pharmacological evidence no longer supports, patients may forgo effective treatment on mistaken grounds. We argue that systemic bioavailability offers a more coherent criterion than anatomical orifice-entry, and that the divergence between religious and pharmacological framings generates concrete obligations for clinical counselling and for interdisciplinary dialogue between scholars and pharmaceutical scientists. Respecting patient autonomy requires that such decisions rest on accurate empirical premises.</p>