JOURNAL SCAN
Omeprazole is a Superior
Gastric Acid Suppressant in Cats
Summarised by Dr Liesel van der Merwe BSVC MMed(Vet)Med Small
Animals
Parkinson K, Tolbert K, Messenger A et al. Evaluation of the Effect of
Orally Administered Acid Suppressants on Intragastric pH in Cats.
Journal of Veterinary Internal Medicine. 2015(29) pp: 104 - 112
Why they did it?
Gastric acid suppressants including H2 receptor antagonists (H2RA) and proton pump inhibitors (PPIs)
are the most widely prescribed medications for the
adjunctive treatment of diseases which disrupt the
gastric mucosal barrier in cats. Because of their small
size and the fact that we are using human formulations - tablets need to be divided to achieve the correct dose. This study was designed to do 3 things:
compare the effect of per os administered fractionated omeprazole tablets, reformulated omeprazole
paste and famotidine on intra-gastric pH in cats, determine in which category of pH ( 0-1, 1-2, 2-3, 3-4,
4-5, 5-6, 6-7, 7-8 ) the pH was for the most time from
days 4-7 of treatment and finally to evaluate the serum levels of omeprazole in the cats on bloods drawn
on day 7 of treatment .
What they did:
Six healthy research colony cats with no evidence
of GI disease were used. In a randomised open-label
4-way crossover design each cat was administered:
placebo (250mg Lactose capsule per os bid), famotidine (0.88 – 1.26mg/kg per os bid), fractionated
omeprazole tablets (0.88 – 1.26mg/kg per os bid or
omeprazole reformulated paste (0.88 – 1.26mg/kg
per os bid) for 7 days followed by a minimum 10 day
washout period.
An omeprazole paste was reformulated using Gastroguard® to a suspension of 10mg/ml by mixing
the paste with cod liver oil (1:39) and storing it at 7°C,
away from light, to be used within 90 days.
On day 4 a Bravo™ pH capsule was fixed into the
stomach endoscopically. Intra-gastric pH recordings
were obtained telemetrically every 6 seconds for
days 4 – 7 of treatment.
Blood samples were obtained from cats receiving
omeprazole at 0.25, 0.5, 1, 2, 4, 6 and 8 hours after
morning administration on day 7.
What they found:
The mean percentage time gastric pH is ≥3 and ≥4
has been found, using meta-analysis in humans , to be
the ideal baseline for mucousal healing, with a goal in
Treatment
% time intra-gastric pH ≥ 3
% time intra-gastric pH ≥ 4
Placebo bid
16. ± 14.2%
9.6 ± 10.1%
humans of being at this level for at least 75% and 67%
of the day respectively. The table below summarises
results for this parameter.
Both omeprazole formulations, dosed bid, significantly increased intra-gastric pH compared to either the
famotidine or the placebo (P<0.0001). No significant
differences were found between the fractionated or
reformulated omeprazole comparing the above parameter.
The area under the concentration –time curve (AUC),
median and range has been shown to best reflect the
inhibitory effects of omeprazole on gastric acid secretion and was similar between both formulations. The
Tmax (time to maximum serum levels) was earlier in
the paste formulation
Take home message:
These results suggest that either of the omeprazole
formulations, dosed twice daily, provide significantly
superior acid suppression in cats compared to famotidine (H2RA) or placebo. The fractionated enteric
coated omeprazole tablet remains efficacious despite
disruption of its enteric coating, and shows no significant difference to the reformulated omeprazole
paste.
Ranitidine bid
42.7 ± 18.6%
22.4 ± 14.7%
Omeprazole oid
68.4 ±35%
57.8 ± 37.1%
Omeprazole bid
73.89 ± 23.2%
55.7 ± 25.3%
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