title: Effects of Lemon and Seville Orange Juices on the Pharmacokinetic Properties of Sildenafil in Healthy Subjects.
abstract: OBJECTIVE
  Several severe drug interactions have been reported when sildenafil, a potent drug for the treatment of erectile dysfunction, is co-administered with drugs or herbal remedies that inhibit cytochrome P450 (CYP) 3A4. This study evaluates the effects of two citrus fruit juices, lemon and Seville orange, on the pharmacokinetics of sildenafil in male healthy subjects following a single oral dose.
  
  
  METHODS
  We conducted an open-label, three-way crossover study in nine healthy male volunteers. Participants received a single oral dose of sildenafil (50 mg) after pretreatment with 250 mL of either water (control), undiluted lemon juice, or Seville orange juice for 3 consecutive days. All subjects were monitored for adverse effects during the study period. Plasma samples were collected for 12 h after dosing and analyzed for sildenafil concentration.
  
  
  RESULTS
  Compared with pretreatment with water, Seville orange juice significantly increased the area under the plasma concentration-time curve from time zero to infinity and the peak plasma concentration of sildenafil by 44 % (90 % confidence interval [CI] 30-60) and 18 % (90 % CI 108-129), respectively, without affecting the time to reach peak plasma concentration. Additionally, Seville orange juice significantly reduced the apparent oral clearance of sildenafil by 30 % (90 % CI 63-75) without affecting its elimination half-life. In contrast, lemon juice did not cause any significant alterations in the pharmacokinetics of sildenafil. There was no significant treatment-related adverse effects reported during the study.
  
  
  CONCLUSIONS
  Although it is considered as a moderate CYP3A4 inhibitor, Seville orange only caused a mild increase in exposure to sildenafil after a single oral dose, without manifestation of any adverse effects. The enhanced bioavailability of sildenafil by Seville orange may be attributed to inhibition of its intestinal first-pass effect (CYP3A4 and or p-glycoprotein). Lemon juice, in contrast, had no effects on the pharmacokinetics of sildenafil.
authors.affiliation: Faculty of Pharmacy, Kafrelsheikh University, Kafr el-Sheikh, Egypt.
authors.forename: Khaled S
authors.initials: KS
authors.lastname: Abdelkawy
authors.affiliation: Faculty of Pharmacy, Tanta University, Tanta, Egypt.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Donia
authors.affiliation: School of Pharmacy, Pacific University, 222 SE 8th Ave., Hillsboro, OR, 97123, USA.
authors.forename: R Brigg
authors.initials: RB
authors.lastname: Turner
authors.affiliation: School of Pharmacy, Pacific University, 222 SE 8th Ave., Hillsboro, OR, 97123, USA. Fawzy.elbarbry@pacificu.edu.
authors.forename: Fawzy
authors.initials: F
authors.lastname: Elbarbry
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D002957:Citrus / Q000737:chemistry / Q000378:metabolism*; D032084:Citrus sinensis; D018592:Cross-Over Studies; D007172:Erectile Dysfunction / Q000188:drug therapy / Q000378:metabolism; D018565:Food-Drug Interactions; D000067030:Fruit and Vegetable Juices; D006207:Half-Life; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D000068677:Sildenafil Citrate / Q000008:administration & dosage / Q000493:pharmacokinetics*; D064804:Urological Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D064804:Urological Agents; D000068677:Sildenafil Citrate