Misoprostol: veterinary dose and monograph

At a glance

Drug class

Gastrointestinal

Also known as

Cytotec, Misoprost, Prostaglandin E1 analogue

Species with doses

Dogs, Cats and Horses

General dose range

0.002–0.005 mg/kg PO q8h — check the species tables for the indication

Routes

PO

Last reviewed

1 October 2026

Indications

• Prevention of NSAID-induced gastric/duodenal ulceration in high-risk patients
• Treatment of established NSAID gastropathy (with NSAID withdrawal)
• Gastroprotection when an NSAID must be continued
• (Specialist use: cervical relaxation/parturition induction protocols — by experienced clinicians only)

Misoprostol dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• NSAID-ulcer prevention/treatment: Papich 5e: 2–5 µg/kg q12h PO. Plumb’s p.851: 2–5 µg/kg PO q8–12h; 3 µg/kg q12h is as effective as q8h for aspirin injury (Ward 2003); 3 µg/kg three times daily (Leib 2008). Abortifacient — pregnant women must avoid handling.
• Atopic dermatitis (adjunct): Papich 5e and Plumb’s p.851 (Olivry 2003): 5 µg/kg PO three times daily; 6 µg/kg q8h for 30 days (Campbell 1999). Modest benefit.
• Pyometra / metritis (with aglepristone): Plumb’s p.851 (Fontbonne 2007): aglepristone 10 mg/kg SC on days 1, 2, 8, 15 and 29 with misoprostol 10 µg/kg PO twice daily on days 3–12.

Cats

• Gastroprotection (less commonly used): Papich 5e: cats 2–4 µg/kg q12h PO. Monitor for GI upset.

Horses

• Gastric ulcer syndrome / colitis (adjunct): Papich 5e: 5 µg/kg q12h PO. Plumb’s p.851: 5 µg/kg PO q8h for equine gastric ulcer syndrome (Buchanan & Andrews 2003) or acute colitis (Atherton 2009).

Contraindications

PREGNANCY — absolute (causes uterine contraction, abortion); pregnant women must not handle crushed/broken tablets. Known prostaglandin hypersensitivity. Use cautiously in inflammatory bowel disease (diarrhoea). Not a substitute for stopping the offending NSAID where possible.

Species-specific warnings

Dogs: Do not use in pregnant bitches — abortion. Counsel owners on glove use and to keep tablets away from pregnant household members.

Adverse effects

• Diarrhoea and abdominal cramping (common, dose-related)
• Vomiting, flatulence
• Uterine contraction / abortion (pregnant animals)
• Anorexia

Drug interactions

• NSAIDs: the very situation it is co-prescribed for (counteracts NSAID GI toxicity)
• Magnesium-containing antacids: worsen misoprostol-induced diarrhoea
• Oxytocin / other uterotonics: additive uterine stimulation

Pregnancy and lactation

Contraindicated — abortifacient (uterine stimulant). Pregnant staff/owners must avoid handling broken tablets and wear gloves. Keep away from breeding females not intended to abort.

Monitoring

• GI tolerance (diarrhoea/cramping) — give with food, reduce dose if troublesome
• Resolution of melaena/haematemesis in treated ulceration
• Confirm patient is not pregnant before dispensing
• Owner handling precautions (gloves; pregnant persons must not handle)

Toxicity and overdose

Overdose primarily causes severe GI signs (cramping, profuse diarrhoea, vomiting), and can cause sedation, tremor, fever and hypotension at very high doses. The serious hazard is uterine/abortive effect in pregnancy and accidental human (especially pregnant) exposure.

Management: No specific antidote. Supportive — fluids to correct diarrhoea-related losses, anti-emetic/antidiarrhoeal symptomatic care, and monitoring. Effects are short-lived as the drug is rapidly metabolised.

Clinical pearls

• The one gastroprotectant that targets the actual mechanism of NSAID ulcers (prostaglandin replacement) rather than just acid
• Reserve for high-risk NSAID patients — diarrhoea/cramping limit routine use; PPIs (omeprazole) are easier first-line acid suppressants
• Never give to, or let pregnant people handle, this drug — it is a potent abortifacient
• Give with food and start at the lower dose to improve GI tolerance
• If an ulcer is established, stop the NSAID; misoprostol supports healing but is not a licence to continue the NSAID unprotected

Mechanism of action

As a PGE1 analogue it binds gastric mucosal prostaglandin (EP) receptors to (1) inhibit parietal-cell acid secretion and (2) exert cytoprotection — increasing mucus and bicarbonate secretion and mucosal blood flow. This directly replaces the protective prostaglandins that NSAIDs eliminate by inhibiting COX-1, addressing the cause of NSAID ulceration rather than only suppressing acid. Prostaglandin-E activity on uterine smooth muscle produces contractions.

Formulations and products

• 100 mcg tablet (0.1 mg)
• 200 mcg tablet (0.2 mg)
• Cytotec — 200 mcg tablet, Tablet (human-label)
• Misoprost — 25 / 100 / 200 mcg tablet, Tablet (human-label)

Storage

Tablets: store at ≤25 °C in a dry place, in the original sealed blister (moisture-sensitive). Handle with gloves; keep away from pregnant individuals.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other gastrointestinal drugs

• Metoclopramide
• Metronidazole
• Mineral Oil (Liquid Paraffin)
• Mirtazapine
• Omeprazole
• Pantoprazole
• Ranitidine
• S-Adenosylmethionine (SAMe)

Frequently asked questions