Misoprostol
Misoprostol protects gastrointestinal mucosa and is used for selected equine glandular gastric disease; it also has uterotonic effects.
Group
Prostaglandin E1 analogue
Mechanism of Action
Activates prostaglandin receptors, supporting mucosal protection and promoting cervical and uterine activity.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Gastrointestinal mucosal protection | 2–5 mcg/kg | PO | Every 12 h | Do not use in: Pregnancy |
| Atopic dermatitis | 5 mcg/kg | PO | Every 8 h | Do not use in: Pregnancy |
| Gastrointestinal mucosal protection | 2–5 mcg/kg | PO | Every 6 h | Do not use in: Pregnancy |
| Gastrointestinal mucosal protection | 2–5 mcg/kg | PO | Every 8–12 h | Do not use in: Pregnancy |
| Aspirin-associated gastric-injury prevention | 3 mcg/kg | PO | Every 8 h | Do not use in: Pregnancy |
| Aspirin-associated gastric-injury prevention | 3 mcg/kg | PO | Every 12 h | Do not use in: Pregnancy |
| Atopic dermatitis | 6 mcg/kg | PO | Every 8 h | Up to 30 days; Do not use in: Pregnancy |
| Aglepristone-associated pyometra protocol | Reference only | PO | Misoprostol 10 mcg/kg twice daily on days 3-12 with aglepristone 10 mg/kg SC on days 1, 2, 8, 15 and 29; evaluate infection, uterine drainage and clinical response. Do not flatten the calendar into misoprostol alone. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Gastrointestinal mucosal protection | 2–4 mcg/kg | PO | Every 12 h | Do not use in: Pregnancy |
| Combined medical pregnancy termination | Reference only | PO | Misoprostol 200 mcg/cat every 12 hours until abortion begins, combined with aglepristone or mifepristone. Do not use without the complete combination protocol; higher standalone doses have greater adverse effects. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Glandular gastric disease or right dorsal colitis | 5 mcg/kg | PO | Every 12 h | Do not use in: Pregnancy |
| Equine gastric ulcer syndrome | 5 mcg/kg | PO | Every 8 h | Do not use in: Pregnancy |
Indications
- Selected NSAID-associated ulcer prevention
- Equine glandular gastric disease and selected right dorsal colitis
- Selected canine atopic dermatitis
Contraindications
- Pregnancy for gastrointestinal or dermatologic treatment
- Pregnant people must avoid exposure.
Interactions
- Guidance advises against concurrent omeprazole for its equine gastrointestinal use.
Adverse effects
- Diarrhoea, vomiting and abdominal discomfort
- Uterine contractions and pregnancy loss
Toxicity
Assess gastrointestinal effects and reproductive status after excess exposure.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Misoprostol 100 mcg tablet | Tablet | 100 mcg / tablet | PO |
| Misoprostol 200 mcg tablet | Tablet | 200 mcg / tablet | PO |
Monitoring and Administration
Handle carefully, particularly around pregnant people.
Evidence of gastric protection is strongest for aspirin-associated injury; benefit for corticosteroid-related bleeding has not been demonstrated.
Use in reproductive termination requires a complete combined-drug protocol, not isolated misoprostol dosing.
Vaginal pregnancy-termination protocols use misoprostol 1-3 mcg/kg once daily after confirmed mid-gestation pregnancy, with dinoprost 0.1 mg/kg SC every 8 hours for 2-3 days then 0.2 mg/kg every 8 hours to effect; ultrasound follow-up is required. The vaginal route is not represented by the current route list. A mare cervical-relaxation case applied 1000 mcg locally after uterine lavage with oxytocin 20 IU IM then every 6 hours overnight; it is a case-specific procedure, not a universal fixed dose.