By DR. Maria Hassan (Pharm-D)
Beta blockers, also called as beta–adrenergic blocking agents a class of drugs that bind to beta-adrenoceptors and prevent the binding of norepinephrine and epinephrine to those receptors.So this inhibits normal sympathetic effects, Therefore, beta-blockers/beta–adrenergic blocking agents are also called sympatholytics drugs.that causing decreased heart rate,cardiac contractility,cardiac work load,(AVN)atrioventricular node conduction,bronchoconstriction, peripheral vasoconstriction, and metabolic imbalances
Classification of beta-blockers
(1)-Non-Selective beta-blockers(1st Generation)
First generation of beta-blockers are non-selective beta-blockers that blocks both beta-1 (β1) and beta-2 (β2) adrenoceptors.nonselective beta blocker, is the first-line drug in the management of essential tremor,portal hypertension,migraine prophylaxis,and thyroid storm.
First generation beta blockers drugs included propranolol(Inderal),nadolol,timolol maleate,penbutolol sulfate,sotalol hydrochloride and pindolol.
(2)-Selective beta-blockers (1st Generation)
Second generation of beta-blockers are cardioselective in that they are selective for β1 adrenoceptors.but their selectivity is lost at higher doses of drugs.Cardioselective beta blockers have a lower side-effect profile and are preferred in the management of coronary heart disease,, compensated heart failure,acute coronary syndrom,and certain types of arrhythmias.
Second generation beta blockers drugs included metoprolol, acebutolol hydrochloride , bisoprolol fumarate, esmolol hydrochloride, betaxolol hydrochloride , and acebutolol hydrochloride.
(3)-Mixed Properties Beta-blockers(3rd Generation)
Third generation beta-blockers have mixed properties maybe nonselective or selective, and they have the additional ancillary property of vasodilation. Nebivolol is one of the the newer 3rd generation beta-blockers drug. It is unique in the class, since apart from its cardioselectivity, it also produces nitric oxide-mediated vasodilation. As a result, its hemodynamic profile is mostly different from traditional beta-blockers..
When beta-blockers are used?
Beta-blockers are not given as a first treatment if a patient having only high blood pressure. This medication is used to prevent, improve, treat the symptoms in patient who got these issue that is given below.
- Irregular heart rhythm
- Heart failure
- Chest pain (angina)
- Heart attack
- Certain types of tremors
- In less common cases such as liver problems, anxiety.and glaucoma as an eye drops
- If beta-blockers are good to control high blood pressure in patientswith proper dose, then there are some side effects due with high dosage or other drug interactions.
Most common side effects are given below;
- Cold hands and feet.
- Weight gain
- Shortness of breath
- Trouble in sleeping
These Beta-blockers are also not used in diabetic patients because in insulin-dependent diabetic patients, beta-blockers can prolong, enhance, or change the symptoms of hypoglycemia, on the other hand hyperglycemia appears to be the major risk in noninsulin-dependent diabetics. beta-blockers/beta–adrenergic blocking agents can potentially increase blood glucose concentrations and antagonize the action of oral hypoglycemic drugs. Therefore If using in diabetic patients its important to check blood sugar regularly.It effects on cholesterol and slight rise in triglyceride a type of fat in blood and result in reduction of good cholesterol in the body. Patient should not abruptly stop taking a beta-blocker because doing so it could increase a risk of a sudden heart attack or other heart problems.
What are the most common side effects of beta- blockers?
- Poor circulation
- Gastrointestinal symptoms
- Sexual dysfunction
Which is the best beta-blocker?
Propranolol and atenolol have been studied most intensively in hypertension.
When should beta-blockers be taken morning or night?
Patient can take them in morning at meal time or at bedtime. When take with food, patient may have fewer side effect because the body absorbs the drug slower.
Do beta-blockers weaken the heart?
When taken in high doses these blockers can worsen heart failure, causes bradycardia, produces wheezing and worsening lung diseases.
Cautions with other drugs interactions
Some medicines that interfere with beta-blockers including beta-blocker eye drops
- Medicines for diabetes, particularly insulin.
- Medicines to treat nose or sinus congestion or other cold remedies.
- Medicines for asthma or chronic obstructive pulmonary disease.
- Medicines for allergies such as epinephrine, adrenaline.
- Other medicines that can lower patient’s bp. these include some ant-depressants, nitrates (for chest pain), muscle relaxant like tamsulosin.
- NSAIDS such as ibuprofen.