Propantheline Bromide

What is propantheline bromide?

Propantheline bromide (brand name: Pro-Banthine®) is an antimuscarinic used to treat muscle spasms, incontinence, diarrhea, and sometimes slow heart rate. In horses, it is used to relax the muscles for procedures in the colon.

Its use in cats, dogs, and horses to treat diarrhea and other disorders is off label (extra label). 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 propantheline bromide given?

• Propantheline bromide is given by mouth in the form of a tablet or a compounded liquid. In some countries, it may also be available as an injection.
• Measure liquid forms carefully.
• Give the oral form on an empty stomach; however, if vomiting occurs when dosed on an empty stomach, try giving future doses with a small treat or a small amount of food.
• Always allow free access to water while giving this medication.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.

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?

Propantheline bromide may cause the following side effects:

• Dry mouth
• Dry eyes
• Fast heart rate
• Difficulty urinating
• Constipation
• Vomiting and drooling (in cats)

Serious adverse reactions may occur. If any of the following signs develop, stop giving propantheline bromide and contact your veterinarian immediately:

• Prolonged constipation (more than 2 days)
• Inability to urinate

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 (e.g., irregular breathing, rash, fever, puffiness and swelling around the face) and notify your veterinarian if you have any concerns.  

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?

DO NOT USE propantheline bromide in:

• Pets that are allergic to it or similar drugs
• Pets with certain heart, bladder, or intestinal problems
• Pets with glaucoma
• Pets with myasthenia gravis (a nerve disorder)

USE WITH CAUTION in:

• Pets with liver, kidney, or heart disease
• Pets with high thyroid levels
• Pets with high blood pressure
• Pets with an enlarged prostate
• Pets with infection in the intestines
• Pets that are very old or very young
• Pets that are pregnant or nursing

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with propantheline bromide:

• Antihistamines
• Antiarrhythmics
• Benzodiazepines
• Nitrofurantoin
• Phenothiazines
• Sympathomimetics
• Thiazide diuretics

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

Is any monitoring needed with this medication?

• Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
• Heart rate and heart rhythm may need to be monitored.
• At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.

How do I store propantheline bromide?

• Store this medication at room temperature and protect from light.
• Keep the container out of reach of children and pets.

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. Be prepared to provide information about the product and your pet's weight and symptoms.