Gastroduodenal ulceration in dogs on NSAIDs: does misoprostol prevent aspirin-induced ulceration? — POSSIBLE

In dogs receiving long-term NSAIDs, does misoprostol vs no prophylaxis reduce endoscopically confirmed gastroduodenal ulceration?

Shelf #399 · gate-verified and displayed under the developer's blinded-trial rule

POSSIBLE: In dogs given high-dose aspirin, adding misoprostol reduced endoscopically confirmed gastroduodenal injury in two controlled studies. In Murtaugh 1993 (a randomized, double-blind study in 18 arthritic dogs on aspirin 25 mg/kg three times daily for 14 days), the misoprostol group had significantly less gastroduodenal hemorrhage and ulceration and a significantly lower prevalence of vomiting than the excipient control group (P < 0.05 for both; that record gives no per-arm rates). In Johnston 1995 (18 mixed-breed dogs, three groups of six), total endoscopic lesion scores in the misoprostol-plus-aspirin group were 12.0, 12.7 and 16.2 on days 5, 14 and 30 versus 26.0, 23.8 and 21.5 in the aspirin-only group. Design class (a): randomisation and blinding are both established by a carded record — Murtaugh 1993 states 'a randomized, double-blind, controlled study' in its own wording, with publication type Randomized Controlled Trial and MeSH Double-Blind Method; Johnston 1995 states neither randomisation nor blinding in its record and none is claimed for it. The honest limits: all the carded evidence is against aspirin at challenge doses (25–35 mg/kg three times daily) over 14–30 days, not against modern NSAIDs or truly long-term clinical use; the samples are tiny (18 dogs per study); the endpoint is endoscopic lesions, a surrogate for clinical ulceration and bleeding; and the one randomised trial reports significance without per-arm rates. That is why the stamp is POSSIBLE and not higher. Drafted Nov 10, 2026 (VetMed build, topic #399); all figures from abstracts fetched and verified at drafting.

Murtaugh 1993: arthritic dogs on aspirin given misoprostol had significantly less gastroduodenal hemorrhage and ulceration and less vomiting than aspirin-only controls over 14 days (P < 0.05)

Randomized, double-blind, controlled study (record's own wording: 'A randomized, double-blind, controlled study'; publication type: Randomized Controlled Trial; MeSH includes Double-Blind Method)

Who: Dogs: 18 arthritic dogs administered aspirin (25 mg/kg of body weight, PO, q 8 h) and excipient (control group, n = 8) or aspirin and misoprostol (100 micrograms, PO, q 8 h; n = 10) over a 14-day treatment period, in a clinical (client-owned arthritic dog) setting. Groups were primarily compared by sequential gastroduodenoscopy, changes in PCV, and prevalence of clinical signs of gastrointestinal disturbance.

Result: The misoprostol/aspirin-treated group had significantly (P < 0.05) less gastroduodenal hemorrhage and ulceration and a significantly (P < 0.05) lower prevalence of vomiting than did the control group. The record gives no per-arm event rates or lesion scores, so no absolute rates can be stated from this record.

Watch out: Small (18 dogs), short (14 days) and aspirin-only: the aspirin dose (25 mg/kg three times daily) is a challenge regimen, not typical modern NSAID therapy, and the endpoint is endoscopic hemorrhage and ulceration rather than clinical bleeding. The abstract reports statistical significance without the underlying rates, so the size of the effect cannot be quantified from this record.

Murtaugh RJ, Matz ME, Labato MA, Boudrieau RJ. Use of synthetic prostaglandin E1 (misoprostol) for prevention of aspirin-induced gastroduodenal ulceration in arthritic dogs. J Am Vet Med Assoc. 1993;202(2):251-6. PMID: 8428830. Registry ID: none in the record. MeSH: Animals · Aspirin/adverse effects*, therapeutic use · Diarrhea/chemically induced, prevention & control, veterinary · Dog Diseases/chemically induced, drug therapy, prevention & control* · Dogs · Double-Blind Method · Duodenoscopy/veterinary · Female · Gastrointestinal Hemorrhage/prevention & control, veterinary · Gastroscopy/veterinary · Male · Misoprostol/therapeutic use* · Osteoarthritis/drug therapy, veterinary* · Peptic Ulcer/chemically induced, prevention & control, veterinary* · Vomiting/chemically induced, prevention & control, veterinary

Johnston 1995: endoscopic lesion scores in dogs on aspirin plus misoprostol were roughly half those on aspirin alone — total scores 12.0 vs 26.0 (day 5), 12.7 vs 23.8 (day 14) and 16.2 vs 21.5 (day 30)

Controlled experimental study in three parallel groups (record does not state randomisation or blinding; publication type: Journal Article)

Who: Dogs: 18 adult mixed breed dogs in a research setting, in 3 groups of 6. Group I received misoprostol alone (3 micrograms/kg PO tid). Group II received misoprostol (3 micrograms/kg PO tid) and aspirin (35 mg/kg PO tid). Group III received aspirin alone (35 mg/kg PO tid). Endoscopy was performed on days 0, 5, 14 and 30; five regions of the upper gastrointestinal tract were scored from 1 to 12 based on submucosal hemorrhage, erosion or ulceration, and a total score assigned from the sum of all regions.

Result: A significant difference in mean gastroduodenal lesion score was found among all groups at 5, 14 and 30 days. Mean total scores on days 5, 14 and 30 were: group I (misoprostol alone) 5.0, 5.2, 9.0; group II (misoprostol plus aspirin) 12.0, 12.7, 16.2; and group III (aspirin alone) 26.0, 23.8, 21.5. The record's conclusion was that misoprostol effectively decreased endoscopically detectable mucosal lesions in dogs given aspirin.

Watch out: Randomisation and blinding are not stated in this record and none is claimed for it; the blinding/randomisation basis for the shelf comes from Murtaugh 1993. Groups are six dogs each, the aspirin dose is a high challenge dose, and the lesion score is a qualitative endoscopic scale — scores are not ulcer counts, so no ulceration rates can be derived from them. Even the misoprostol-only group's scores rose by day 30 (9.0), so the scale has a background floor.

Johnston SA, Leib MS, Forrester SD, Marini M. The effect of misoprostol on aspirin-induced gastroduodenal lesions in dogs. J Vet Intern Med. 1995;9(1):32-8. PMID: 7891360. Registry ID: none in the record. MeSH: Animals · Aspirin/adverse effects* · Dog Diseases/chemically induced, drug therapy* · Dogs · Duodenal Ulcer/chemically induced, complications, drug therapy, veterinary · Female · Male · Misoprostol/therapeutic use* · Peptic Ulcer Hemorrhage/drug therapy, etiology, veterinary* · Stomach Ulcer/chemically induced, complications, drug therapy, veterinary · Treatment Outcome

Synthesis: misoprostol roughly halves endoscopic gastroduodenal injury in dogs on high-dose aspirin — POSSIBLE, on aspirin-challenge evidence only

Synthesis

Who: Synthesis of the cards above: Murtaugh 1993 (randomized, double-blind study, 18 arthritic dogs on aspirin 25 mg/kg tid for 14 days, misoprostol 100 micrograms tid vs excipient) and Johnston 1995 (18 mixed-breed research dogs, aspirin 35 mg/kg tid with or without misoprostol 3 micrograms/kg tid, endoscopy to day 30).

Result: (1) Aspirin alone produces substantial endoscopic injury: mean total lesion scores of 26.0, 23.8 and 21.5 at days 5, 14 and 30 in Johnston. (2) Adding misoprostol cut those scores to 12.0, 12.7 and 16.2 at the same timepoints. (3) The randomised, double-blind trial (Murtaugh) independently found significantly less gastroduodenal hemorrhage and ulceration and less vomiting with misoprostol (P < 0.05). Two consistent controlled studies, one of them a blinded randomised trial in clinical arthritic dogs, support POSSIBLE.

Watch out: The mined question asks about long-term NSAIDs generally; the carded evidence answers it only for aspirin, at high challenge doses, over 14–30 days, with endoscopic lesions as the endpoint. No carded record tests misoprostol against a modern NSAID (such as a coxib or carprofen) or measures clinical ulceration, gastrointestinal bleeding or perforation. A diclofenac study in 50 mongrel research dogs randomised to five groups (highly selective vagotomy [HSV] alone; diclofenac alone; HSV then diclofenac; diclofenac plus misoprostol; HSV then diclofenac plus misoprostol) (PMID: 8662142), in which misoprostol alone did not significantly protect the gastric (p = 0.08) or duodenal (p = 0.65) mucosa, was deliberately not carded: its population (mongrel dogs allocated across vagotomy and non-vagotomy arms) and question (whether HSV, misoprostol, or both protect against diclofenac injury) are a different home, and it is cross-pointed here instead.

Synthesis of Murtaugh RJ et al. PMID: 8428830; Johnston SA et al. PMID: 7891360. Registry IDs as on the individual cards.

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