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Chris
Member
Username: stevens
Post Number: 349
Registered: 8-2002
| | Posted on Tuesday, Aug 7, 2007 - 11:39 pm: |   |
I went to CostCo today to stock up on ranitidine for my horse. As some may recall, he'd been scoped and diagnosed with an ulcer about 7 years ago (5 years before I bought him) and had been on a regiment of 16 75mg ranitidine twice a day for a total of 1200 mg a day.
Well, long story relatively short, CostCo no longer appears to be selling generic ranitidine and instead has generic famotidine (20mg) tablets.
After some research, I've found that famotidine is generally accepted as being twice as "effective" as ranitidine, so I'm thinking that 600 mg of famotidine would be as effective as his current dose of ranitidine.
If anyone has any additional information on famotidine, I'd greatly appreciate it. I have enough ranitidine to last through this week.
Thanks!
Chris |
Sara Wolff
Member
Username: mrose
Post Number: 3032
Registered: 1-2000
| | Posted on Wednesday, Aug 8, 2007 - 12:25 am: | |
My doctor has me on Famotidine and it seems to help. I don't know how that translates to horses though.  |
Chris
Member
Username: stevens
Post Number: 350
Registered: 8-2002
| | Posted on Wednesday, Aug 8, 2007 - 10:11 am: | |
Thanks Sara, I'm glad it's helping you.
So much of the information out there on gastric ulcers in horses is anecdotes as opposed to real data. I'm pretty confident that I won't be poisoning him, but at least want to increase the odds of giving an effective dose.
I'm going to email my regular vet too and ask.
Thanks for the response.
Chris |
Martha E. Mitchell
Member
Username: mitma
Post Number: 93
Registered: 11-2006
| | Posted on Wednesday, Aug 8, 2007 - 12:47 pm: | |
Chris,
For HUMAN use, 150 mg of Ranitidine = 20 mg of Famotidine, thus Famotidine is about 7x more potent than Ranitidine... this is data based on treating ulcers in humans (i.e., maintenance vs. active ulcer therapy), though these drugs are used to treat other conditions, such as GERD... (which is why I often administer these drugs to patients prior to general anesthesia)... I have no idea if this info can be translated into equine medicine, but based on these human equivalents, you should only use eight 20 mg tablets, which is 160 mg daily in your horse. Good Luck!
Martha |
Chris
Member
Username: stevens
Post Number: 351
Registered: 8-2002
| | Posted on Wednesday, Aug 8, 2007 - 1:29 pm: | |
Martha,
Thanks so much for the information. A great example of why I'm being so cautious. Maybe the information I found on the web was related to active therapy and not maintenance, but it is maintenance that interests me.
Thanks again,
Chris |
Robert N. Oglesby DVM
Moderator
Username: dro
Post Number: 18982
Registered: 1-1997
| | Posted on Friday, Aug 10, 2007 - 12:27 pm: | |
In the only study that I can find that compares the two drugs, ranitidine at the recommended dosages was better (higher ph and longer acting) than famotidine at extrapolated human doses (Equine Vet J Suppl. 1992 Feb;(11):52-5. The effects of famotidine, ranitidine and magnesium hydroxide/aluminium hydroxide on gastric fluid pH in adult horses.).
DrO |
Chris
Member
Username: stevens
Post Number: 352
Registered: 8-2002
| | Posted on Friday, Aug 10, 2007 - 4:15 pm: | |
Thanks Dr. O.
I also got a response from my regular vet. She went through her pharmacology books and found a recommended famotidine dosage of 2mg/kg or in my boy's case, 1100 mg twice a day. She also consulted with a medicine internist at another vet clinic (I was lucky enough to ask the question just before she called the other vet on another topic so got a free ride) who mentioned that she had not used famotidine on horses but had on cats.
Bottom line, given her understanding that the bioavailability of H2 antagonists is low in general (10-30%) she suggested keeping Ulcergard on hand and using it when the horse might be stressed.
I'll probably keep up with the ranitidine (if I can find it) as a preventive for him or placebo for me . I already keep Ulcergard on hand.
Chris |
Martha E. Mitchell
Member
Username: mitma
Post Number: 99
Registered: 11-2006
| | Posted on Saturday, Aug 11, 2007 - 12:52 am: | |
Chris,
I feel obligated to comment further and in doing so I don't mean to raise alarm, but I am concerned that your vet's recommended dosage of famotidine at 2 mg/kg twice daily may be in error... I really think that she has quoted you the dosing that corresponds to ranitidine...(you state that famotidine for your horse, 1100 mg twice daily = 2200mg daily). I promise you that amount of famotidine is NOT in any way similar to your horse's current ranitidine dose of 1200 mg a day (please tell me if I read your initial or subsequent postings incorrectly...) Though it is true that the bioavailability of H2 antagonists is low (that's true in humans also), that would in no way affect potency (which is an intrinsic drug property). Famotidine is the more potent drug, by about 7x, so to get a similar effect from it, you would use about 7x less famotidine compared to ranitidine, again about 160 mg based on your horse's current total daily ranitidine dose of 1200 mg. Really, Famotidine, 20 mg = Ranitidine, 150 mg. Good Luck! Perhaps, Dr. O would comment about the dosing used in the study which showed more success with ranitidine???
Martha |
Robert N. Oglesby DVM
Moderator
Username: dro
Post Number: 18997
Registered: 1-1997
| | Posted on Saturday, Aug 11, 2007 - 6:36 pm: | |
Three different dosages of famotidine were studied: 0.5, 1.0, and 2.0 mg/kg bodyweight (bwt) as a one time administered dose.
DrO |
Chris
Member
Username: stevens
Post Number: 356
Registered: 8-2002
| | Posted on Saturday, Aug 11, 2007 - 10:26 pm: | |
Martha and Dr. O.
Thanks for the continued interest in this thread.
My apologies for the incomplete information regarding my vet's recommended dosages. It was indeed 2 mg/kg of famotidine. What I failed to include is that she recommends a ranitidine dose of 3000mg 2 to 3 times a day. She also mentioned that she did not think the 1200 mg which I give twice a day (for a total of 2400mg/day; instead of the erroneously stated 1200mg/day in the original post) was enough to make a difference in a horse the size of my boy (17.2 1200lbs).
So I understand her recommendation as either 6000 to 9000mg of ranitidine or 2200mg of famotidine, which still would be excessive famotidine using a 1:7 ratio.
I think it's going to be easier, certainly not cheaper, just to stick with the Ulcergard.
Again, my apologies for the sloppy posts earlier.
Regards,
Chris |
Martha E. Mitchell
Member
Username: mitma
Post Number: 104
Registered: 11-2006
| | Posted on Monday, Aug 13, 2007 - 12:22 am: | |
Ahhh... Good Luck! I'm off to take my own dose of "anti-ulcer" medicine now!
Martha |
