What is misoprostol?
Misoprostol (brand names Cytotec®, Arthrotec®) is a prostaglandin E1 analog drug. It is used off label (extra label) to treat or prevent stomach ulcers due to NSAID use in cats, dogs, and horses. It can also be used in combination with other medications to treat uterine infections, protect the kidneys, treat skin allergies, or to terminate pregnancy.
Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.
How is misoprostol given?
- Misoprostol is given by mouth in the form of a tablet. It may also be compounded into a liquid to be given by mouth.
- Give with food to prevent stomach upset.
- Measure liquid forms carefully.
- Pregnant women should avoid handling this medication and should avoid direct contact with the pet’s saliva, urine, feces, or cat litter, as misoprostol can cause miscarriage.
This medication should take effect within 1 to 2 hours; however, effects may not be noted outwardly, and laboratory tests may need to be done to evaluate this medication’s effectiveness.
What if I miss giving my pet the medication?
If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.
Are there any potential side effects?
Misoprostol may cause minor side effects. These effects usually resolve on their own after a few days, but if they do not, contact your veterinarian:
- gastrointestinal upset (diarrhea, vomiting, stomach pain, gas)
Serious adverse reactions may rarely occur. If any of the following signs develop, stop giving misoprostol and contact your veterinarian immediately:
- seizures
- uterine contractions (in females)
- vaginal bleeding (in females)
Drug sensitivities can develop over time, with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment.
Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.
Are there any risk factors for this medication?
Misoprostol should NOT BE USED in pets that:
- are allergic to it
- are pregnant (unless it is being used to terminate the pregnancy)
Misoprostol should be USED WITH CAUTION in pets that:
- have brain or heart vessel disease
- have seizures
- are lactating
Are there any drug interactions I should be aware of?
The following medications should be used with caution when given with misoprostol: antacids with magnesium, oxytocin, and phenylbutazone. Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.
Is any monitoring needed with this medication?
- No specific monitoring is required while your pet is taking this medication.
- Your veterinarian may monitor your pet to be sure that the medication is working.
- At home, monitor for serious side effects and contact your veterinarian if they occur.
How do I store misoprostol?
- Store at room temperature in a tight container and protected from light.
- For compounded forms, follow the storage directions on the label.
What should I do in case of emergency?
If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.
