An open label, balanced, randomized, single-dose, two-treatment, two-sequence, two-period, crossover oral drug-drug interaction study of spironolactone (perpetrator) and Digoxin (substrate drug) in healthy adult human subjects under fasting condition.
Drug interaction studies between spironolactone and digoxin, particularly studies in which digoxin was administered intravenously (Waldorf, S 1978; Fenster, P.E. 1984), indicate that spironolactone may decrease the renal clearance of digoxin by 18-25%, and increase the (area under curve) AUC of digoxin by 35-44%. Although the radioimmunoassay used in the study may be confounded, these results suggest that inhibition of P-gp in the renal proximal tubules may be possible. To account for possible renal P-gp inhibition, subjects in the test group will be pretreated with spironolactone for about 5 days to allow accumulation of some of the metabolites which have a long half-life (e.g., canrenone \~33 hours) and continue to be treated with spironolactone while digoxin is renally eliminated from the body. Based on this assessment, the FDA suggested study design is Treatment A: Single dose of digoxin alone. Treatment B: Digoxin + Spironolactone; Day 1- 9: Spironolactone single dose; Day 6: Digoxin single oral dose. Also, digoxin has a long half-life of 1.5-2 days, and the Pharmacokinetic (PK) sampling scheme of up to 72 hours may not be enough to characterize the elimination kinetics of digoxin. Hence, the plasma concentrations of digoxin up to 96 hours (4 days) postdose is considered This will allow you to detect possible differences in the clearance of digoxin mediated by an interaction with P-gp in the renal proximal tubules. The study also involves collecting urine samples and measuring renal clearance (CLR) and unchanged drug excreted in urine (fe) for digoxin.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
28
The intervention is for study of drug drug interaction of digoxin when administered with spironolactone oral suspension
The intervention is for study of drug drug interaction of digoxin when administered with spironolactone oral suspension
ClinSync Clinical Research Pvt. Ltd.
Hyderabad, Telangana, India
Dogoxin Plasma Data for Cmax
Primary Pharmacokinetic parameter The following pharmacokinetic parameters for Digoxin were obtained using non-compartmental method Cmax, AUC0-96, and tmax using plasma data, Renal clearance (CLR) /Percent Recovered, Unchanged drug excreted in urine (fe)/Amount Recovered using urine data.
Time frame: 4 days
Digoxin Plasma Data for AUC0-96
Area under the plasma concentration versus time curve from time 0 to the 96 hour time point concentration.
Time frame: 4 days
Digoxin Plasma Data for Tmax
If the maximum value occurs at more than one time point, Tmax is defined as the first time point with this value.
Time frame: 4 days
ECG Measurement Will be Performed to Evaluate Any Changes in the QT Interval
ECG will be performed at 1.00 and 3.00 hours post dose in each period on Day 6 and at check-out of each period of the study
Time frame: 4 days
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