BRAND NAME: TENORMIN
HOW THIS MEDICATION IS USED
Certain heart diseases, such as subaortic stenosis of dogs, and hypertrophic cardiomyopathy of cats, involve the development of thickened, inflexible heart muscle. These heart diseases can benefit from what is called "beta blockade." This means that atenolol can relax the stiff heart muscle and slow the heart rate, allowing for more efficient filling of the heart chambers.
Atenolol might also be used in the treatment of high blood pressure or to treat heart arrhythmias where the heart rhythm is simply too fast (and the heart does not have time to properly fill between beats).
Sometimes atenolol is used in preparing feline patients for surgical treatment of hyperthyroidism, where there is often heart disease as described.
Atenolol has a tendency to drop blood pressure through its effects on the heart. This may or may not be a desired effect. Low blood pressure in a patient may manifest as lethargy/listlessness. If this side effect is observed it may be well worth having the patient's blood pressure checked. Listlessness from low blood pressure would be noted as soon as within an hour of oral administration. Atenolol slows the heart rate and can weaken contraction of the heart; these may be harmful depending on what type of heart disease is present. These effects, for example, could make heart failure worse.
Some patients develop diarrhea from taking atenolol. If this or any other side effect becomes problematic, it is recommended to withdraw the atenolol gradually rather than suddenly.
Other beta blockers have created problems facilitating airway constriction in asthmatic patients but atenolol, being specific to beta-one receptors at usual doses, does not have this problem.
INTERACTIONS WITH OTHER DRUGS
Drugs that promote the function of the sympathetic nervous system may be blocked by atenolol and may in turn block the effectiveness of atenolol. Such drugs include: phenylpropanolamine (used for urinary incontinence) and terbutaline (an airway dilator).
Combining atenolol with acepromazine (a tranquilizer), furosemide (a diuretic), or hydralazine (a blood vessel dilator) may enhance the low blood pressure side effect of atenolol. Combining atenolol with heart medications called "calcium channel blockers" may enhance the heart rate slowing effects of atenolol.
CONCERNS AND CAUTIONS
Page posted: 1/10/2013