Marks S. Diseases of the pharynx and esophagus. In: Ettinger S, Feldman E, Côté E, eds. Textbook of Veterinary Internal Medicine. 8th ed. Elsevier; 2017:1476–1490.
Harvey CE, O’Brien JA, Durie VR, Miller DJ, Veenema R. Megaesophagus in the dog: a clinical survey of 79 cases. J Am Vet Med Assoc. 1974;165(5):443–446.
Washabau RJ. Gastrointestinal motility disorders and gastrointestinal prokinetic therapy. Vet Clin North Am Small Anim Pract. 2003;33(5):1007–1028. doi:10.1016/S0195-5616(03)00076-7
Boudrieau R, Rogers W. Megaesophagus in the dog: a review of 50 cases. J Am Anim Hosp Assoc. 1985;21(1):33–40.
Glidewell H. Clinical signs of idiopathic megaesophagus in Great Dane puppies. Vet Med Small Anim Clin. 1983;78:37–45.
Guilford W, Strombeck D. Diseases of swallowing. In: Guilford WG, Center SA, Strombeck DR, Williams DA, Meyer DJ, eds. Strombeck’s Small Animal Gastroenterology. 3rd ed. WB Saunders Co; 1996:211–238.
McBrearty AR, Ramsey IK, Courcier EA, Mellor DJ, Bell R. Clinical factors associated with death before discharge and overall survival time in dogs with generalized megaesophagus. J Am Vet Med Assoc. 2011;238(12):1622–1628. doi:10.2460/javma.238.12.1622
Simpson J. Management of megaoesophagus in the dog. In Pract. 1994;16(1):14–16. doi:10.1136/inpract.16.1.14
Patel DA, Kim HP, Zifodya JS, Vaezi MF. Idiopathic (primary) achalasia: a review. Orphanet J Rare Dis. 2015;10:89. doi:10.1186/s13023-015-0302-1
Bortolotti M, Mari C, Lopilato C, Porrazzo G, Miglioli M. Effects of sildenafil on esophageal motility of patients with idiopathic achalasia. Gastroenterology. 2000;118(2):253–257. doi:10.1016/S0016-5085(00)70206-X
Bortolotti M, Mari C, Giovannini M, Pinna S, Miglioli M. Effects of sildenafil on esophageal motility of normal subjects. Dig Dis Sci. 2001;46(11):2301–2306. doi:10.1023/A:1012383424783
Bortolotti M, Pandolfo N, Giovannini M, Mari M, Miglioli M. Effect of sildenafil on hypertensive lower oesophageal sphincter. Eur J Clin Invest. 2002;32(9):682–685. doi:10.1046/j.1365-2362.2002.01059.x
Eherer AJ, Schwetz I, Hammer HF, et al. Effect of sildenafil on oesophageal motor function in healthy subjects and patients with oesophageal motor disorders. Gut. 2002;50(6):758–764. doi:10.1136/gut.50.6.758
Moreland RB, Goldstein I, Traish A. Sildenafil, a novel inhibitor of phosphodiesterase type 5 in human corpus cavernosum muscle cells. Life Sci. 1998;62(20):309–318. doi:10.1016/S0024-3205(98)00158-1
Rhee PL, Hyun JG, Lee JH, et al. The effect of sildenafil on lower esophageal sphincter and body motility in normal male adults. Am J Gastroenterol. 2001;96(12):3251–3257. doi:10.1016/S0002-9270(01)03884-9
Zhang X, Tack J, Janssens J, Sifrim DA. Effect of sildenafil, a phosphodiesterase-5 inhibitor, of oesophageal peristalsis and lower oesophageal sphincter function in cats. Neurogastroenterol Motil. 2001;13(4):325–331. doi:10.1046/j.1365-2982.2001.00271.x
Quintavalla F, Menozzi A, Pozzoli C, et al. Sildenafil improves clinical signs and radiographic features in dogs with congenital idiopathic megaesophagus: a randomized controlled trial. Vet Rec. 2017;180(16):404. doi:10.1136/vr.103832
Harris RA, Grobman ME, Allen MJ, et al. Standardization of a videofluoroscopic swallow study protocol to investigate dysphagia in dogs. J Vet Intern Med. 2017;31(2):383–393. doi:10.1111/jvim.14676
Walker DK. Pharmacokinetics and metabolism of sildenafil in mouse, rat, rabbit, dog and man. Xenobiotica. 1999;29(3):297–310. doi:10.1080/004982599238687
Haines JM, Khoo A, Brinkman E, Thomason JM, Mackin AJ. Technique for evaluation of gravity-assisted esophageal transit characteristics in dogs with megaesophagus. J Am Anim Hosp Assoc. 2019;55(4):167–177. doi:10.5326/JAAHA-MS-6711
Akabane R, Sato T, Sakatani A, Miyagawa Y, Tazaki H, Takemura N. Pharmacokinetics of single-dose sildenafil administered orally in clinically healthy dogs: effect of feeding and dose proportionality. J Vet Pharmacol Ther. 2018;41(3):457–462. doi:10.1111/jvp.12487
Eardley I, Ellis P, Boolell M, Wulff M. Onset and duration of action of sildenafil for the treatment of erectile dysfunction. Br J Clin Pharmacol. 2002;53(suppl 1):61S–65S. doi:10.1046/j.0306-5251.2001.00034.x
Nichols DJ, Muirhead GJ, Harness JA. Pharmacokinetics of sildenafil citrate after single oral doses in healthy male subjects: absolute bioavailability, food effects and dose proportionality. Br J Clin Pharmacol. 2002;53(suppl 1):5S–12S. doi:10.1046/j.0306-5251.2001.00027.x
Brown AJ, Davison E, Sleeper MM. Clinical efficacy of sildenafil in treatment of pulmonary arterial hypertension in dogs. J Vet Intern Med. 2010;24(4):850–854. doi:10.1111/j.1939-1676.2010.0517.x
Kellum HB, Stepien RL. Sildenafil citrate therapy in 22 dogs with pulmonary hypertension. J Vet Intern Med. 2007;21(6):1258–1264. doi:10.1111/j.1939-1676.2007.tb01947.x
Kempf J, Lewis F, Reusch CE, Kook PH. High-resolution manometric evaluation of the effects of cisapride and metoclopramide hydrochloride administered orally on lower esophageal sphincter pressure in awake dogs. Am J Vet Res. 2014;75(4):361–366. doi:10.2460/ajvr.75.4.361
Ullal TV, Kass PH, Conklin JL, Belafsky PC, Marks SL. High-resolution manometric evaluation of the effects of cisapride on the esophagus during administration of solid and liquid boluses in awake healthy dogs. Am J Vet Res. 2016;77(8):818–827. doi:10.2460/ajvr.77.8.818
Advertisement
To determine whether delivery of compounded liquid sildenafil directly to the stomach of dogs with megaesophagus (ME) would affect esophageal clearance, regurgitation frequency, body weight, or quality of life.
10 client-owned otherwise healthy dogs with stable ME.
A randomized crossover study was performed. Dogs received either sildenafil (1 mg/kg, PO, q 12 h) or a placebo for 14 days, followed by a 7-day washout period, then the opposite treatment for 14 days. Esophageal clearance time was assessed by means of videofluoroscopy prior to treatment and on day 1 of each treatment period. Owners maintained logs of regurgitation episodes and quality of life.
Compounded liquid sildenafil moved into the stomach during 21 of 30 (70%) videofluoroscopy sessions. Sildenafil resulted in a significant reduction in the number of regurgitation episodes (median, 3.5 episodes/wk; range, 0 to 14.5 episodes/wk), compared with baseline (median, 6.5 episodes/wk; range, 1.5 to 19.5 episodes/wk) and the placebo (median, 4 episodes/wk; range, 0 to 28 episodes/wk), and a significant increase in body weight (median, 22.05 kg; range, 6 to 26.3 kg), compared with baseline (median, 21.55 kg; range, 5.1 to 26.2 kg) and the placebo (median, 22.9 kg; range, 5.8 to 25.9 kg). There were no differences in esophageal clearance times or quality-of life-scores between sildenafil and placebo.
Although significant differences with placebo administration were identified, clinically relevant improvements were not seen with the use of compounded liquid sildenafil in dogs with ME.