Background: The present article is related to in-vitro and in-vivo herb-drug interaction studies.
Objectives: This study aimed to investigate the effect of Nigella sativa and fenugreek on the pharmacodynamics and
pharmacokinetics of amlodipine.
Method: Hypertensive rats of group-I were treated with amlodipine and rats of group-II and III were treated with N.
sativa, and N. sativa + amlodipine and fenugreek, and fenugreek + amlodipine, respectively. Systolic blood pressure
(SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) of group-I, II and III rats were measured by
the “tail-cuff system”.
Results: N. sativa, as well as fenugreek, reduced the SBP, DBP and MBP. Simultaneously, administration of
fenugreek + amlodipine or N. sativa + amlodipine showed better control of BP. Individually, fenugreek, as well as N.
sativa, showed a surprising reduction in the heart rate. There was no remarkable effect of any of these two herbs on
Cmax, AUC0-t, Kel, and terminal elimination half-life of amlodipine, but fenugreek altered the Tmax of amlodipine
significantly, from 2 ± 1.2h in control to 7.2 ± 1.7h in fenugreek treated group, probably by delaying the absorption.
Conclusion: Results of pharmacodynamics and pharmacokinetics studies suggested that simultaneous administration
of fenugreek or N. sativa with amlodipine improved the pharmacological response of amlodipine in hypertensive rats,
though there was no remarkable change in pharmacokinetic parameters (Cmax, Kel, elimination t1/2, and AUC0-t).