A Closer Look at Beta Blockers

• Beta-adrenergic antagonists treat hypertension and are commonly referred to as beta blockers.  
• These drugs decrease blood pressure by inhibiting beta-1 adrenergic receptor sites in the heart muscle and conduction system. 
• This medication can be given with or without meals.  

Beta Blockers

Beta-adrenergic antagonists, also known as beta-blockers, are used to treat hypertension. These drugs are also used in treating other conditions, such as ocular hypertension and long-term prevention of angina.  

Common examples of beta-adrenergic antagonists include: 

• Acebutolol  
• Atenolol  
• Betaxolol  
• Bisoprolol  
• Carteolol  
• Metoprolol tartrate 
• Nadolol  
• Pindolol  
• Propranolol hydrochloride 
• Timolol 
  

Propranolol is used for the prevention of frequent, severe, uncontrollable, or disabling migraine or vascular headaches.

Beta blockers used for ocular hypertension are:

• Betaxolol 
• Carteolol 
• Timolol 
  

Beta-blockers decrease blood pressure by inhibiting beta-1 adrenergic receptor sites in the heart muscle and conduction system. That decreases heart rate and reduces the force of the heart’s contractions, resulting in lower demand for oxygen. It also lowers heart rate, heart workload, and the heart’s output of blood.  

Beta Blocker Drug Interactions

Some common drug interactions with beta-blockers are: 

• Antacids delay the absorption of beta-adrenergic blockers when given together. If the patient has been prescribed both drugs, administer them at different times so they do not interact with each other.  
• Beta-blockers, when given with lidocaine, can result in lidocaine toxicity.  
• The doses of insulin and antidiabetic drugs might need to be altered when given beta-adrenergic blockers.  
• Theophylline is unable to elicit bronchodilation when given beta-adrenergic blockers. 
• Beta-blockers, when administered with diuretics, result in increased hypotensive effects.  

Adverse Reactions of Beta Blockers

The common adverse reactions of beta-adrenergic blockers are: 

• Bradycardia 
• Angina 
• Heart failure 
• Arrhythmias  
• AV block 
• Fainting  
• Fluid retention 
• Peripheral edema 
• Dizziness  
• Shock  
• Nausea and vomiting 
• Diarrhea 
• Significant constriction of the bronchioles. Therefore, it is advised not to administer beta-blockers in patients with asthma as it can worsen the pre-existing condition and result in severe bronchoconstriction.  

To stop taking beta blockers, you should taper it off. Stopping it abruptly, especially when given in high doses, can result in angina, hypertension, arrhythmias, and acute myocardial infarction. Therefore, if you want to stop it, reduce the doses slowly and gradually. 

Nursing Assessment

• Before starting the therapy, ask the patient if they have a history of asthma. Also, check the patient’s blood pressure, heart rhythm, and pulse rate. Check it regularly with the therapy as well.  
• Monitor the ECG closely, especially when the dose is adjusted or given intravenously. 
• Keep an eye on the patient’s vital signs and monitor them for toxicity and adverse reactions. 
• Check the patient for wheezes if they develop asthma due to beta blockers therapy.  
• Before giving the drug, measure the apical pulse and blood pressure.  
• Monitor blood tests such as liver function tests with the therapy and check for drug interactions or adverse reactions.  
• Evaluate the patients’ and family members’ knowledge of the drug.
  

Nursing Implementation

With beta blockers therapy, you must keep the following considerations in your mind: 

• Do not crush the sustained release preparations.  
• Sustained-release tablets and extended-release tablets cannot be used interchangeably. Therefore, exercise caution and do not give them as an alternative to each other.  
• If CNS toxicity occurs, take precautions as soon as possible and inform the healthcare provider promptly.  
• You will have to adjust the dose according to the patient’s tolerance and blood pressure- an indicator of response to drug therapy. You should monitor it to know the effectiveness of the beta blockers therapy.  
• Advise the patient not to make sudden movements and help them cope with orthostatic hypotension.  
• In an emergency, use intravenous therapy to get a prompt response.  
• If the patient’s systolic blood pressure is below 90 mm Hg or heart rate is below 60 beats/minute, as a nurse, you should withhold the drug and ask the physician how and when you should administer the dose. Otherwise, it can result in life-threatening bradycardia and hypotension.  
• You can administer them with or without meals.  
• If the patient is undergoing surgery, make sure to inform the anaesthesiologist that the patient takes beta blockers and when they have taken the last dose.  
• Do not discontinue beta blockers abruptly, especially when given intravenously.  
• Provide detailed teaching to the patient.  

Nursing Evaluation

As a nurse, you should ensure the following things with  beta-adrenergic antagonist therapy: 

• The patient and his family have in-depth knowledge and understanding of this therapy.  
• The patient’s blood pressure is within normal limits.   
• The patient has no injury due to orthostatic hypotension.  

The Bottom Line

Beta blockers play an essential role in the management of hypertension and angina prevention. However, their use should be avoided in patients with asthma due to their Broncho constrictive actions. Before starting the therapy, take a detailed patient history. 

Read More