Herb–Drug Interaction Between the Extract of Hibiscus sabdariffa L. and Hydrochlorothiazide in Experimental Animals

Abstract Decoctions of Hibiscus sabdariffa L. (Family Malvaceae) are very popular for the preparation of homemade refreshing drinks and are also used medicinally for a variety of ailments. Particularly remarkable are the various scientific reports supporting diuretic and antihypertensive potentials. It is therefore not unusual for patients who are on orthodox antihypertensive medications to use medicinal H. sabdariffa drinks concomitantly without regard to the possibility of herb–drug interactions. This possibility necessitated this study in which the pharmacokinetic and pharmacodynamic interactions of H. sabdariffa extract (HSE) and hydrochlorothiazide (HCT), a commonly prescribed diuretic drug, were examined. The effects of concomitant administration of HSE on urine volume, urine pH, and urinary concentrations of sodium, bicarbonate, and chloride ions, as well as on the pharmacokinetic parameters of HCT, were determined in experimental rats and rabbits. Co-administration of HSE with HCT caused a signifi...