All about Atenolol - Your Questions, Answered!

What is Atenolol?

Atenolol is a drug known as a beta-blocker that can lower stress on the heart and blood vessels and improve the way heart muscles use oxygen, keeping the heart beating at a normal rate. 

Atenolol is a common treatment for cats who have a condition that causes the heart muscle walls to thicken (hypertrophic cardiomyopathy), making it harder for the heart to function efficiently. This type of drug improves heart functions by helping control the heart rate, reducing the risk of certain abnormal heart rhythm (arrhythmias), decreasing blood pressure, and improving oxygen use by the heart muscle.  

This medication is also used to treat a heart defect known as subvalvular aortic stenosis (SAS) in dogs. This heart defect causes the narrowing of tissue located just below the aortic heart valve. This makes it more difficult for the heart to pump blood out to the body.  

Atenolol is used to treat irregular heartbeats  from the lower chambers of the heart (ventricular premature beats or ventricular tachycardia).

Additionally, atenolol is used to treat extra heartbeats (atrial premature beats) and abnormally fast heart rates (supraventricular tachycardia) in the heart’s upper chambers or atria. 

As well as regulating heart rates, atenolol can be prescribed to manage high blood pressure (systemic hypertension) or an overactive thyroid (hyperthyroidism)—a condition that can cause an increase in heart rate.

How do I give my pet atenolol?

Atenolol can be given once or twice daily with food (morning dosing may be preferred, especially in cats). This medication comes in pill form and a flavored liquid. This drug must be given to your pet in the dosage prescribed by your veterinarian. Atenolol can be taken with other medications to treat heart disease when instructed by CVCA.

Never skip doses or stop giving this medication, as your pet’s heart rate could quickly rise again. If you miss a dose, give it to your pet as soon as you remember, if it is not too close to the next scheduled dose. It is important to never give your pet two doses at once.

What are the potential side effects?

Like most medications, it is possible for side effects to occur while taking atenolol. If your pet experiences any of these side effects, please contact CVCA immediately. 

Side effects can include low heart rate resulting in lack of energy, depression, and weakness. Atenolol may have some effect on blood sugar control in diabetic patients. 

What are the risks when taking this medication?

Atenolol must be used with caution in patients with decreased heart muscle strength and/or congestive heart failure, as this medication may worsen symptoms. Particular caution is also required when taken by patients with airway disease or asthma.

Should my pet be monitored while on this medication?

Most pets that start atenolol need to have the heart rate and rhythm checked 2 weeks after starting the medication. Based on that visit, the dose may be changed to improve the effect of the drug.

What drug interactions should I be aware of while my pet is taking atenolol?

Please let the doctors at CVCA know about all your pet’s medications before beginning a treatment that includes atenolol. There is an increased risk of bradycardia, and low blood pressure (hypotension) when combined with other drugs such as acepromazine, amlodipine, diltiazem, enalapril, or benazepril.

The doctors at CVCA have already taken this into account, but please feel free to contact us to discuss any concurrent medications your pet may be prescribed.

Please contact CVCA if your pet requires anesthesia, as dose adjustments may be necessary.

What are the standard dosages for atenolol?

The most common method to give atenolol to your pet is oral tablets. Standard dosages include 25mg, 50mg, and 100mg pill sizes.

What should I do in case of an overdose?

If your pet has ingested an overdose, emergency veterinary attention is immediately required.