By Rania Gollakner, BS, DVM, MPH

What is misoprostol?

Misoprostol (brand name: Cytotec®, Arthrotec®) is a prostaglandin E1 analog used to treat or prevent stomach ulcers due to NSAID use. It can also be used in combination with other medications to treat uterine infections, protect the kidneys, treat skin allergies, or to terminate pregnancy.

Its use in cats, dogs, and horses to treat stomach ulceration or to treat reproductive conditions is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions 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 as it can cause miscarriage, and should also avoid direct contact with the pet’s saliva, urine, feces, or cat litter.

This medication should take effect within 1 to 2 hours; however, effects may not be noted outwardly and therefore 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 when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

The most common side effect is gastrointestinal upset such as diarrhea, vomiting, stomach pain, and gas. These effects usually resolve on their own after a few days, but if they do not, contact your veterinarian. Serious side effects may rarely occur, and include seizures, or in females, uterine contractions, and vaginal bleeding.

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?

Do not use misoprostol in pets that are allergic to it or in pets that are pregnant unless it is being used for the purpose of pregnancy termination. It should be used very cautiously in pets that have brain or heart vessel disease, are lactating, or have seizures.

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, or phenylbutazone.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working. 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.

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