Update (June 19, 2026): Omeprazole Lowers Clopidogrel Metabolite but Not Platelet Function in Healthy Cats - Crossover RCT

TL;DR

A randomized crossover study in healthy cats found concurrent omeprazole lowered plasma clopidogrel active metabolite by day 10 but did not significantly change platelet function over short-term use, tempering concern about this drug interaction in cats.

What just dropped

• In a 2-sequence, 2-period crossover study, ten healthy cats received clopidogrel alone or clopidogrel with omeprazole for 10 days each, separated by a washout (Plante 2024, https://europepmc.org/articles/PMC11586560).
• Plasma clopidogrel active metabolite concentrations were significantly lower on day 10 in cats receiving both drugs versus clopidogrel alone (P < .02).
• Despite this pharmacokinetic change, two of three platelet-function assays (Multiplate Analyzer and PFA-100) detected no difference in platelet function between treatment groups.
• The authors concluded that short-term concurrent omeprazole and clopidogrel altered pharmacokinetics but did not appear to significantly alter platelet function in healthy cats.

Context

In people, the clopidogrel-omeprazole interaction is a recognized concern because both are handled by overlapping hepatic pathways, and reduced clopidogrel activation can blunt antiplatelet effect. Whether this matters clinically in cats has been unclear. This study suggests the pharmacokinetic signal is real but the short-term pharmacodynamic consequence is small in healthy animals. It sits alongside the ACVIM consensus on rational use of gastrointestinal protectants, which challenges routine, indication-poor prescribing of proton pump inhibitors in dogs and cats and notes documented adverse effects of long-term PPI use (Marks 2018, https://europepmc.org/articles/PMC6271318).

What this changes in the omeprazole evergreen

Our omeprazole and gastroprotectants review (https://www.thevoyage.ai/forvets/knowledge/omeprazole-gastroprotectants-dogs) emphasizes judicious PPI use. This feline study adds a specific, frequently asked drug-interaction data point: in healthy cats, short-term co-administration with clopidogrel changed metabolite levels but not measured platelet function. The investigators studied healthy cats over a short period, so caution is warranted before generalizing to cats with thrombotic disease or long-term combined therapy.

References

1. Plante C, Lee PM, Haines JM, Nelson OL, Martinez SE, Court MH. 2024. The effect of concurrent clopidogrel and omeprazole administration on clopidogrel metabolism and platelet function in healthy cats. J Vet Intern Med 38(6):3206-3214. https://europepmc.org/articles/PMC11586560
2. Marks SL, Kook PH, Papich MG, Tolbert MK, Willard MD. 2018. ACVIM consensus statement: Support for rational administration of gastrointestinal protectants to dogs and cats. J Vet Intern Med 32(6):1823-1840. https://europepmc.org/articles/PMC6271318

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