Effect of sildenafil citrate on postprandial gallbladder motility.
OBJECTIVE
Sildenafil stimulates the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway through inhibition of type 5 phosphodiesterase. NO-cGMP pathway causes smooth muscle relaxation. The aim of this study is to evaluate the effects of sildenafil on gallbladder motility.


METHODS
Twenty healthy male volunteers (21-35 years old) participated in this randomized, double blind, crossover, and placebo-controlled study. Oral sildenafil (50 mg) or placebo was randomly dispensed to each volunteer on two consecutive days. After the sildenafil or placebo, a special meal with a high fat content was administered. Gallbladder volume was measured using sonography preprandially and at 5, 15, 30, 60, 120 and 180 minutes postprandially.


RESULTS
Sildenafil showed an inhibitory effect on gallbladder contraction in healthy volunteers that began at 30 minutes. Gallbladder volumes showed significant differences at 30 minutes following the test meal (approximately 50-60 min after the sildenafil intake), between placebo (15.4 +/- 5.1 mL) and the sildenafil groups (19.3 +/- 6.1 mL) (P < 0.05). In addition, gallbladder volume was significantly higher during the refilling phase in the sildenafil group (P < 0.05 at 180 min). Maximal contraction was achieved at 60 minutes in each group.


CONCLUSIONS
Sildenafil constituted a significant inhibitory effect on gallbladder discharge in healthy individuals when compared with placebo group. Because of this inhibitory effect, sildenafil consumption for long periods may potentiate risks of gallbladder disorders and gallstone formation resulting from disturbed gallbladder motility.
Department of Radiology, Kocatepe University Faculty of Medicine, Afyon, Turkey. bd2002tr@yahoo.com
Bumin
B
Degirmenci
Murat
M
Acar
Ramazan
R
Albayrak
Aylin
A
Yucel
Alpay
A
Haktanir
Reha
R
Demirel
Ender
E
Ellidokuz
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000284:Administration, Oral; D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005500:Follow-Up Studies; D005704:Gallbladder / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology; D016473:Gallbladder Emptying / Q000187:drug effects*; D006801:Humans; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage*; D010879:Piperazines / Q000008:administration & dosage*; D019518:Postprandial Period / Q000187:drug effects*; D011446:Prospective Studies; D011687:Purines; D012016:Reference Values; D000068677:Sildenafil Citrate; D013450:Sulfones; D014463:Ultrasonography
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D015106:3',5'-Cyclic-GMP Phosphodiesterases