Propranolol (Inderal®, Intensol®) for Dogs and Cats

 

Overview of Propranolol for Dogs and Cats

Propranolol, also known as Inderal® or Intensol®, is used for the treatment and prevention of cardiac arrhythmias and reduces cardiac output and lowers high blood pressure in dogs and cats.

The autonomic (involuntary) nervous system is divided into the sympathetic (fight or flight response) and parasympathetic branches.

Sympathetic activity is communicated to tissues through involuntary (autonomic) nerve impulses and through the blood.

Cells contain targets, called receptors, which are stimulated by chemicals released from nerves or glands. In the sympathetic system, the chemical transmitter released by nerves is called norepinephrine. The transmitter chemical released by the adrenal glands is called epinephrine or adrenaline. The receptors for these chemicals are the alpha and beta-adrenergic receptors.

The effects of beta-adrenergic receptor stimulation include increases in blood sugar, faster heart rate, stronger heart contraction and increased oxygen consumption, resulting in an increase in the blood pressure. In addition, stimulation of the receptors also results in relaxation of the bronchial tree, causing opening of the airways as well as dilation of some blood vessels.

Propranolol belongs to a general class of drugs known as beta blockers. Other related drugs in this class include Brevibloc® (esmolol), Tenormin® (atenolol) and Lopressor® (metoprolol).

The effects of beta-blockers are especially prominent in the heart, though other organs also can be affected.

Propranolol decreases heart rate, cardiac output, the amount of oxygen the heart muscle needs and blood pressure.

Propranolol is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.

This drug is not approved for use in animals by the Food and Drug Administration but it is prescribed legally by veterinarians as an extra-label drug.

Brand Names and Other Names of Propranolol

This drug is registered for use in humans only.

Human formulations: Inderal® (Wyeth/Ayerst), Intensol® (Roxane) and various generic preparations

Veterinary formulations: None

Uses of Propranolol for Dogs and Cats

The primary use of beta-adrenergic blockers in animals is treatment (and sometimes prevention) of cardiac arrhythmias. Commonly treated heart-rhythm disturbances are atrial fibrillation and flutter.

Propranolol is also used to treat supraventricular tachycardia and premature ventricular complexes (PVCs).

Propranolol reduces cardiac output and lowers high blood pressure (systemic hypertension).

Reducing the heart rate and strength of heart muscle contraction can be beneficial to some cats and dogs suffering from the condition called hypertrophic cardiomyopathy, especially when the heart muscle contracts so vigorously it obstructs the path of the blood.

Propranolol can be used in the management of an overactive thyroid gland (hyperthyroidism) in cats.

Precautions and Side Effects

While generally safe and effective when prescribed by a veterinarian, propranolol can cause side effects in some animals.

Propranolol should not be used in animals with known hypersensitivity or allergy to the drug.

Propranolol can depress heart-muscle function and heart rate, reducing cardiac output. This can be a problem in animals with congestive heart failure and requires very careful dosing.

Propranolol may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with propranolol. Such drugs include sedatives, cimetidine, inslin, lidocaine and theophylline.

Propranolol may cause some animals to become weak due to a slow heart rate or low blood pressure. Rarely, a pet may faint.

How Propranolol Is Supplied

Propranolol is available in 10 mg, 20 mg, 40 mg, 60 mg, 80 mg and 90 mg tablets.

Propranolol extended-release is available in 60 mg, 80 mg, 120 mg and 160 mg capsules.

Propranolol oral solution is supplied as 4 mg/ml, 8 mg/ml and 80 mg/ml.

Propranolol injectable is supplied as 1 mg/ml concentration.

Dosing Information of Propranolol for Dogs and Cats

Medication should never be administered without first consulting your veterinarian.

The typical dose administered to dogs is 0.15 to 0.5 mg per pound (0.3 to 1.0 mg/kg) three times daily.

The typical dose administered to cats is 2.5 to 5 mg per cat twice to three times daily.

Frequently, propranolol is given with other drugs, especially in pets undergoing treatment for heart failure or arrhythmias (abnormal heart rhythm). In these situations, a lower initial dose may be prescribed.

The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse or prevent the development of resistance.