The active ingredient is the same, the problem is that it has to safely get past the stomach and be absorbed in the intestines to have the long lasting effects. The drug is easily broken down by stomach acid, so unless it has the correct 'carrying agent', it won't get to the gut. Even in humans, the instructions are not to crush or bite the pill. It has to have its coating intact in order to get through the human stomach into the intestines.
The makers of Ulcerguard/Gastro Gard spent a lot of time researching their carrying agent to ensure the active ingredient gets past the stomach. Generic brands don't have the same agent, and have not been proven to protect the active ingredient. Crushing or liquifying a human pill would have the same problem, the drug would get quickly processed in the stomach, and not make it into the intestines where it could be slowly absorbed.
Here is an excerpt from a webpage I found that has some good info on ulcer treatments. (
http://www.equinepi.com/faq/ulcers.html#ulcer2)
Ulcer FAQs
Question: What are the common therapies for Ulcers/EGUS?
Answer: Traditionally antacids were used to decrease the discomfort and increase the pH of the stomach contents. The traditional components are usually a combination of magnesium hydroxide and aluminum hydroxide (i.e. Neighlox). The effect of even a large dose (240-360 ml) of these compounds is short lived and would require repeat dosing every 2-6 hours to have any real effect on ulcer healing (Hinchcliff et al, 2004). Additionally these compounds can reduce the absorbability of some other medications given orally. Bismuth compounds, such as Pepto Bismol have not been shown to have any significant effect at all (Picavet, 2002). Various other remedies (i.e. Papaya, Gastrex) have been used as antacid therapy in horses with variable results.
Coating agents such as Sucralfate (dose range from 10-40 mg/kg) also require frequent dosing (every 6-8 hrs) to have an effect. The act by forming a protective gel-like coating over the ulcers themselves, and therefore have no direct healing effect (Robinson, 2003). They are most effective when used in combination with H2 Antagonist drugs (Hinchcliff et al, 2004).
H2 (Histamine receptor) Antagonist drugs act to suppress acid secretion without completely blocking acid production. This class includes drugs such as Cimetidine (15-25 mg/kg), and Ranitidine (6.6 mg/kg) both of which require dosing 4 times per day (every 8 hours) to be effective (Merritt, 2003; Hinchcliff et al, 2004; Robinson, 2003).
Proton Pump inhibitors such as omeprazole paste (Trade Name GastroGard) block the secretion of acid for up to 27 hours at the full dose (Robinson, 2003), therefore making administration of the medication easier to manage. An Australian study found that omeprazole was more effective at healing ulcers than ranitidine with noticeable improvement after 14 days of therapy and lasting benefit greater than 28 days after the therapy (Lester et al, 2005). Recommended dosage of GastroGard is 1 tube per 1000 lb horse per day (4 mg/kg every 24 hours) to promote healing and prevent recurrence of ulcers. A dosage of ½ tube for a 1000 lb horse per day (2 mg/kg every 24 hours) following 28 days of full dose therapy has been shown to prevent recurrence of ulcers (Andrews, 1999). Studies performed in race horses in training, found that a dose of GastroGard paste at ¼ tube per 1000 lb horse per day (1 mg/kg every 24 hours) was effective in both preventing ulcers in horses starting race training (Andrews, 1999; McClure et al, 2005b; White et al, 2003), and in preventing the recurrence of ulcers in horses in race training (McClure et al, 2005c; White et al, 2003).
GastroGard was formulated and manufactured following extensive research to create a unique drug for horses. Although the active ingredient, omeprazole, is used widely in humans, the molecular structure was modified specifically for extended absorption in horses. Therefore, the use of the human formulations of omeprazole may be less effective and require more frequent administration.
Merial, the makers of GastroGard, have now formulated a non-prescription form of the drug omeprazole (1mg/kg dose label) called UlcerGard. Non-prescription medications are not subjected to the same stringent research and quality control procedures as prescription formulations, which is why the non-prescription form can be marketed at a significantly lower cost.
In summary, the recommended dose of GastroGard (the only FDA approved formulation of omeprazole for horses currently) depends on a number of factors such as whether non-healed ulcers are present, whether ulcers were present, but have healed, or whether there are currently no ulcers at all as well as the "stress" the horse in question is being subjected to currently. In general to heal ulcers requires a dose of 1 tube per 1000 lb horse per day (4mg/kg/day) for at least one month. Maintenance or preventative therapy with GastroGard in horses that have ulcers that have healed may only require ¼ to ½ tube per 1000 lb horse per day (1-2 mg/kg/day). Therapeutic dosage is dependent on all of the above factors including the degree of ulceration present, management and the individual horse in question.
In some horse with chronic EGUS which is not responsive to traditional therapy, a bacterial component may be contributing to the syndrome. A combination therapy of 1 tube per 1000 lb horse per day omeprazole paste (4 mg/kg every 24 hrs), metronidazole (15 mg/kg orally every 6-8 hrs) or SMZ's (15-25 mg/kg orally every 12 hrs), and bismuth subsalicylate (3.8 mg/kg every 6 hrs) for a period of 14 days may be effective (Andrews FM,2005).
Lisa
