title: Influence of carvedilol on serum digoxin levels in heart failure: is there any gender difference?
abstract: OBJECTIVE
  The activity of the human cytochrome P450 and P-glycoprotein (P-gp) changes according to gender. The present study evaluated the effect of gender on the influence of carvedilol on serum digoxin levels in patients with heart failure.
  
  
  METHODS
  Twenty-four patients (12 female and 12 male) with New York Heart Association class II-III heart failure were included in the study. Patients were taking oral digoxin (0.0625-0.25 mg, once a day) and were administered oral carvedilol (6.25 mg, two times daily) for 7 days.
  
  
  RESULTS
  In the male group, carvedilol led to statistically significant increases in the area under the concentration time curve to 16 h (AUC(0-16h)) and the peak concentration (C(max)) for digoxin, with no change in time to peak (t(max))(AUC(0-16h)= 24.1+/-9.2 ng.h/ml vs. 15.4+/-5.8 ng.h/ml, p<0.001, C(max)=2.2+/-1.0 ng/ml vs. 1.6+/-0.6 ng/ml, p<0.01, t(max)=2.4+/-2.2 h vs. 2.1+/-1.0 h, p>0.05). In the female group, carvedilol administration did not cause statistically significant change in the AUC(0-16h), C(max), or t(max) for digoxin (p>0.05). In the male group, carvedilol resulted in a significant increase in the AUC(0-16h) and C(max) for digoxin compared with the female group (AUC(0-16h)=24.1+/- 9.2ng.h/ml vs. 17.0+/-6.8 ng.h/ml, C(max)=2.2+/-1.0 ng/ml vs. 1.5+/-0.6 ng/ml, p<0.05, respectively).
  
  
  CONCLUSIONS
  Men seem to have a higher activity relative to women for the drug efflux transporter P-gp. Our results suggest that carvedilol will cause drug interaction with digoxin following the inhibition of P-gp-mediated transcellular transport of digoxin in males.
authors.affiliation: Department of Cardiology, Dokuz Eylul University, School of Medicine, Izmir, Turkey.
authors.forename: Nezihi
authors.initials: N
authors.lastname: Baris
authors.forename: Sule
authors.initials: S
authors.lastname: Kalkan
authors.forename: Sema
authors.initials: S
authors.lastname: Güneri
authors.forename: Volkan
authors.initials: V
authors.lastname: Bozdemir
authors.forename: Hulya
authors.initials: H
authors.lastname: Guven
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D019540:Area Under Curve; D002227:Carbazoles / Q000627:therapeutic use*; D002316:Cardiotonic Agents / Q000097:blood* / Q000493:pharmacokinetics; D000077261:Carvedilol; D004077:Digoxin / Q000097:blood* / Q000493:pharmacokinetics; D004347:Drug Interactions; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006801:Humans; D008297:Male; D011412:Propanolamines / Q000627:therapeutic use*; D012727:Sex Characteristics; D013997:Time Factors
chemical_list: D000959:Antihypertensive Agents; D002227:Carbazoles; D002316:Cardiotonic Agents; D011412:Propanolamines; D000077261:Carvedilol; D004077:Digoxin