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Ranitidine in dogs and cats: the evidence

Ranitidine has been bugging me for a while.  My experience is that it’s very widely used in small animal practice.  Obviously it’s unlicensed.  What is the evidence for its use?

http://www.ncbi.nlm.nih.gov/pubmed/22792515

Lidbury et al found no effect of ranitidine (75mg bid) on GI transit times in dogs

http://www.ncbi.nlm.nih.gov/pubmed/21864875

Favarato et al found no effect of ranitidine (2mg/kg i.v. as single dose) on esophageal pH during ovariohysterectomy in dogs.

http://www.ncbi.nlm.nih.gov/pubmed/15822586

Bersenas et al. found that ranitidine 2mg/kg i.v. q12 hrs did not significantly suppress gastric acid secretion in dogs.  Whereas PPIs certainly did.  ‘Twice daily administration of a suspension of omeprazole [1mg/kg], was the only regimen tested that approached the potential therapeutic efficacy for acid-related disease when assessed by criteria used for human patients.’

So that doesn’t seem to support the use of ranitidine in dogs. Not only does it not appear to be effective -there are also reports of nausea, vomiting and apathy in treated dogs.  How about cats?.  Fortunately there is a nice, up-to-date, randomized, placebo-controlled, crossover trial to address the issue.

http://onlinelibrary.wiley.com/doi/10.1111/jvim.12580/full

Which concludes rather brutally: ‘Only twice-daily PO administered omeprazole significantly suppressed gastric acidity in healthy cats, whereas once-daily omeprazole and standard dosages [1.5-2.3mg/kg q12hrs] of ranitidine were not effective acid suppressants in cats.’

Ranitidine is generally considered to be more potent an H2 blocker than cimetidine.  I’d be very interested to be persuaded otherwise but I’ll be using omeprazole in circumstances where I really need gastric pH control.