Can dogs take propranolol?

In this article:

• What is propranolol used for in dogs?
• Is propranolol safe for dogs?
• Dosage
• Alternatives
• Summary

In this article

• What is propranolol used for in dogs?
• Is propranolol safe for dogs?
• Dosage
• Alternatives
• Summary

Propranolol is a human prescription drug used to treat abnormal heart rhythms in dogs and cats. It works by slowing down the heart rate and weakening the heart’s contractions, so its use is limited to certain types of heart rhythm problems. A veterinarian may use propranolol to treat some types of heart failure or high blood pressure, but they prefer to use other medications.

What is propranolol used for in dogs?

Veterinarians use propranolol in fairly specific circumstances, including heart rhythm irregularities and some cases of high blood pressure. Propranolol can help dogs with some types of heart failure live longer, but it’s not a standard component of the heart failure treatment protocol.

Cardiac arrhythmias

When a dog’s heartbeats aren’t normal, veterinarians call this a “cardiac arrhythmia.” Since heartbeats are a complex interplay of electrical impulses and muscular contractions, the heart’s rhythm can go wrong in many ways. Some types of abnormal heart rhythms are life-threatening emergencies, some are risky, and some are relatively harmless. 

Because there are so many types of heart arrhythmias, veterinarians have a wide selection of drugs to choose from. Each type of heart rhythm drug or “antiarrhythmic” works best for some heart rhythm problems but not others.

Propranolol is a beta-adrenergic blocker or beta blocker. These drugs block the effects of adrenaline and noradrenaline, hormones that excite nerve cells and make the heart beat stronger and faster. As a result, beta blockers slow down the heart and decrease the strength of the heart’s muscles. They also lower blood pressure but it’s not completely clear how that works.

Beta blockers slow down specific nerve signals in the heart, making them a drug of choice if some part of the heart is contracting before it should. This type of arrhythmia is called “increased automaticity.” It happens when the heart’s nerves power up too fast. That is, they generate their electrical potential too early. Enhanced automaticity usually feels like the heart is skipping a beat, fluttering, palpitating, pounding, or jumping. 

There are several types of enhanced automaticity heart rhythm problems including—sometimes—atrial fibrillation. The veterinarian may diagnose the dog with some kind of “premature complex,” such as “supraventricular premature complex.” Or the veterinarian may use the term “tachyarrhythmia,” for “fast rhythm.” All these words mean is some part of the heart is firing or contracting too early. Any one of these types of abnormal heart rhythms is a suitable candidate for propranolol therapy.

Veterinarians usually send caregivers home with propranolol tablets, capsules, or a specially prepared liquid version. Doses are given every eight hours.

Congestive heart failure

In people, beta blockers are a standard part of heart failure treatment. Veterinarians do not use propranolol in the normal course of treating canine heart failure. In fact, using beta blockers for canine heart failure in small animals is controversial. Because propranolol weakens and slows the heart, veterinarians are warned to use it cautiously in any dog with congestive heart failure.

Hypertension

High blood pressure is a common problem in dogs. Veterinarians use a variety of drugs to bring down blood pressure in dogs, but propranolol is not included in treatment protocols.

However, veterinarians may consider using propranolol in dogs that have a very rare form of cancer called pheochromocytoma, a cancer of the adrenal gland. Among the symptoms are high blood pressure and racing heartbeats. The standard treatment is surgery, but the beta blockers atenolol or propranolol may be used to slow down the heart and lower blood pressure.

Is propranolol safe for dogs?

Given as directed and with appropriate monitoring, propranolol is considered safe for dogs. 

Propranolol is never safe to give dogs with:

• A history of allergic reactions to beta blockers
• Symptomatic or worsening heart failure (overt heart failure)
• A heart degree block greater than first-degree
• A type of slow heart rate called sinus bradycardia

Though not contraindicated, veterinary literature warns practitioners never to use propranolol in dogs with:

• Heart failure unrelated to fast heart rates (tachyarrythmias) that can be treated by propranolol
• Conditions that cause airway closure, such as asthma

Because of potential hazards, veterinarians use propranolol cautiously in dogs with:

• Kidney problems
• Liver problems
• Dysfunction of the heart’s “pacemaker” (sinus node)
• Diabetes
• Thyroid disease

Side effects of propranolol in dogs

Propranolol side effects are more likely to be experienced by geriatric dogs or those with worsening heart disease. 

The most common adverse effects of propranolol in dogs are:

• Low blood pressure (hypotension)
• Slow heart rate
• Weakness
• Lack of energy
• Diarrhea
• Depression

The most serious side effects of propranolol in dogs are:

• Dangerously low blood pressure
• Dangerously slow heart rate
• Low blood sugar
• Bronchospasm (closure of small airways)
• Worsening of heart failure

If these happen, call the veterinarian or a veterinary hospital. Signs to watch for include:

• Severe weakness
• Muscle twitches
• Loss of coordination
• Difficulty breathing
• Wheezing
• Rapid breathing
• Slow breathing
• Seizures
• Fainting
• Pale gums
• Altered behavior
• Confusion
• Dizziness
• Collapse or loss of consciousness

Interactions of propranolol with other pet meds

Propranolol has some significant drug interactions, so make sure the veterinarian knows about all the drugs, herbal remedies, vitamins, and supplements regularly given to the dog, particularly:

• Other medications that treat heart rhythms, particularly calcium channel blockers, lidocaine, and digoxin
• Blood pressure medications
• Diuretics
• Insulin
• Thyroid hormones
• Phenothiazines, a family of drugs used for sedation or nausea in dogs
• Anticholinergic drugs, a family of drugs used to treat slow heart rate, nausea, or diarrhea in dogs
• Epinephrine, a rescue medicine for severe allergic reactions or asthma attacks

Drugs similar to epinephrine, called sympathomimetics, can also cause problems when combined with propranolol

• The asthma drug theophylline
• The stomach acid reducer cimetidine
• Fluoxetine, a drug that treats canine anxiety and other behavior disorders

If the dog is being given antacids, the propranolol dose must be given at least one hour before or one hour after an antacid dose. 

Propranolol dosage for dogs

Veterinarians primarily use propranolol to treat heart rhythm abnormalities. The standard dosage is 0.2–1 mg per kilogram, given orally every eight hours. In more urgent cases, veterinarians may use intravenous injections.

Propranolol has other uses, as well. Plumb’s Veterinary Drug Handbook lists the following recommended dosages:

• For susceptible cardiac arrhythmias: 0.1-0.2mg/kg initially given by mouth every 8 hours and then increased to effect with1.5 mg/kg given by mouth every eight hours as the maximum dose OR 0.02–0.1 mg/kg slow intravenous injection

Propranolol is not FDA-approved for use in dogs, so caregivers may need to give the dog human formulations. These come as either tablets or capsules in dosage strengths of 10 mg, 20 mg, 40 mg, 60 mg, and 80 mg. Tablets are usually scored so that they can be divided in half. That means the smallest dose possible is 5 mg. A propranolol oral solution for people is available under the brand name Hemangeol.

Veterinary compounding pharmacies can specially prepare tablets and capsules in smaller doses and provide propranolol liquid for easier dosing.

Can dogs overdose on propranolol?

Dogs can overdose on propranolol. The maximum dosage is not specified in veterinary medicine literature, but the largest recommended dosage is 1.5 mg/kg or 40 mg/dog every eight hours by mouth. Pet parents should consider the prescribed dosage to be the maximum dosage.

If a dog has overdosed on propranolol, immediately call a veterinarian. Get the dog immediate veterinary care if the dog is breathing slowly, loses consciousness, or has seizures.

The most important thing to know about propranolol is that it weakens the heart. An overdose can weaken a dog’s heart too much, so the most common problems associated with a propranolol overdose are a slowed heart rate and low blood pressure. The most common clinical signs of an overdose are listlessness and depression. Other possible problems due to a propranolol overdose include high potassium, fluid in the lungs, lower airway closure, seizures, or respiratory depression.

Can I give my dog propranolol every day?

Propranolol is a long-term and even lifelong treatment for heart rhythm problems in dogs. Daily doses are safe, provided the dog is regularly monitored by both the caregiver and veterinarian.

How to give your dog propranolol

Caregivers should remember that their dog is on propranolol for serious heart problems. Even though three doses are required each day, do not miss a dose. 

• Follow all the prescriber’s instructions.
• Do not change the dose.
• The veterinarian may need to regularly check the dog to make sure treatment is working, and the drug is not causing problems. Keep all appointments.
• Ask the veterinarian what to do in case a dose is missed.
  • Never give a double dose to make up for a missed dose.
• Do not stop giving propranolol to your dog until you talk to the veterinarian. Doses may need to be gradually decreased to prevent withdrawal problems. 
• If you’re unsure how to give a dog tablets or capsules, a veterinary assistant can demonstrate easy and effective methods.
• Liquid versions of propranolol may need to be gently shaken before measuring a dose.
• Always measure doses of liquid propranolol with the oral syringe or dropper included with the medicine.
• Store propranolol tablets or capsules at room temperature. 
• Ask the veterinarian how liquid propranolol should be stored.

Propranolol alternatives for dogs

Propranolol is a common treatment for certain types of abnormal heart rhythms in dogs. If propranolol can’t be used for these conditions, a veterinarian may use another beta blocker, such as atenolol or carvedilol. 

Other medications treat other types of heart rhythm problems: sodium channel blockers such as lidocaine, potassium channel blockers such as amiodarone, or calcium channel blockers such as diltiazem.

Propranolol is not a drug of choice for canine hypertension. Veterinarians use beta blockers such as atenolol when other drugs, such as ACE inhibitors or other antihypertensives, don’t work.

Beta blockers are also not commonly used in dogs with heart failure. There is a risk that beta blockers can worsen heart failure because they weaken and slow down the heart. Instead, beta blockers are an optional add-on treatment to the standard ACE inhibitors, diuretics, pimobendan, and digoxin regimen.

Summary

Veterinarians use propranolol for certain types of heart rhythm problems. In those cases, it is safe for the dog, provided that all the veterinarian’s instructions are followed. Veterinarians may prescribe propranolol for other health problems, but veterinary literature does not consider it a drug of choice for those conditions.