Propranolol

Major Uses

Propranolol is a beta blocker drug used to control the heart rate in dogs and cats suffering from cardiac arrhythmias, such as flutter and atrial fibrillation. The drug also effectively reduces blood pressure and may help treat envenomation and post traumatic stress disorder. In cats, propranolol is also used in the management of hyperthyroidism.

Propranolol works by blocking the effects of beta-adrenergic receptor stimulation to reduce symptoms such as increased blood sugar, rapid heart rate, increased oxygen consumption, and increased blood pressure. The drug is not approved by the Food and Drug Administration for use in animals, but it is prescribed legally as an extra-label drug by veterinarians.

Common Precautions

Propranolol may cause weakness due to a slowed heart rate or reduced blood pressure in some animals. Rarely, this may cause fainting. Other side effects associated with use of this drug include lethargy, diarrhea, and labored breathing.

This drug should be used cautiously in animals with diabetes, kidney disease, liver disease, hyperthyroidism, asthma, or other chronic illnesses. Propranolol can depress heart rate and heart-muscle function, which in turn reduces cardiac output. In animals with congestive heart failure, this effect can be dangerous.

Propranolol is known to interact with various other supplements and medications, including lidocaine, cimetidine, theophylline, insulin, aspirin, phenothiazine, thyroid hormone, digoxin, antacids, negative inotropes, chlorpromazine, calcium channel blockers, procainamide, furosemide, methimazole, hydralazine, epinephrine, quinidine, phenytoin, phenobarbital, rifampin, terbutaline, succinylcholine chloride, and others.

Propranolol should not be used in animals with a known allergy or hypersensitivity to the drug. Any known or suspected overdose should be reported to a veterinarian right away.

Storage

Propranolol should be stored in a light-resistant container, at room temperature, and away from children and animals. The drug should be kept away from direct sunlight and sources of heat.

Administration

Propranolol is available as tablets and extended-release capsules, and as an oral solution. The drug also comes as an injectable in 1 mg/ml concentration.

In dogs, the typical dose of propranolol is 0.15 to 0.5 mg/lb (0.3 to 1.0 mg/kg) three times each day. In cats, the typical dose is 2.5 to 5 mg per cat, two to three times each day. Propranolol is generally given in combination with other medications and this may affect the dose.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

If a dose of propranolol is missed, it should be given right away. If it is almost time for the next dose, the missed dose should be skipped and the normal schedule resumed. Two doses of this medication should not be given at once.