They decrease heart rate (negative chronotropy) and contractility (negative inotropy), lowering blood pressure and cardiac workload.
Before you read
Test yourself first: 5 questions
Question 1 of 5
A client with diabetes takes a beta-blocker (e.g., metoprolol). The nurse teaches that beta-blockers can:
Answer: B. Beta-blockers can MASK the early signs of hypoglycemia (tremor, tachycardia) — sweating may still occur. Teach the client to monitor glucose carefully and recognize sweating/hunger.
Question 2 of 5
A client takes a beta-adrenergic blocker (for example, metoprolol) and uses insulin. Why is this combination a concern related to hypoglycemia?
Answer: B. Beta blockers can mask the adrenergic warning signs of hypoglycemia such as tremor, palpitations, and tachycardia, so a client may not recognize a falling glucose until neuroglycopenic symptoms appear. Diaphoresis is mediated by cholinergic fibers and is often still present. Clients on beta blockers should monitor glucose more closely.
Question 3 of 5
A client with angina is prescribed a beta blocker. The nurse explains that beta blockers relieve angina primarily by which mechanism?
Answer: A. Beta blockers reduce myocardial oxygen demand by decreasing heart rate, contractility, and blood pressure. This lowers the workload of the heart, helping to prevent angina. They do not dilate coronary arteries directly (a mechanism more associated with nitrates), do not dissolve plaque, and do not increase oxygen demand.
Question 4 of 5
The nurse is teaching a client with diabetes who is starting a beta-blocker. Which teaching point is most important to include?
Answer: B. Beta blockers can mask the early adrenergic warning signs of hypoglycemia such as tachycardia, tremors, and palpitations, so a diabetic client may not feel a low blood sugar coming on. The client should monitor blood glucose more closely; sweating, which is cholinergically mediated, is still present. Beta blockers do not raise blood sugar to dangerous levels, eliminate the need for monitoring, or get taken only when symptoms occur.
Question 5 of 5
A client with asthma who is also being treated for hypertension has a new prescription for a nonselective beta-blocker. The nurse recognizes that this combination is a concern for which reason?
Answer: B. Nonselective beta-blockers block beta-2 receptors in the lungs and can cause bronchoconstriction, potentially triggering severe bronchospasm in clients with asthma. They are generally contraindicated or used with caution in asthma. They can also blunt the response to beta-2 agonist bronchodilators. The nurse should clarify the order with the provider.
Keep the streak going with more questions like these, each with a full rationale.
What is beta blockers?
They are used for hypertension, angina, heart failure, dysrhythmias, and post-MI protection. Memory aid: beta blockers 'put the brakes' on the heart, so they slow rate and lower pressure.
Key points to remember
- They decrease heart rate (negative chronotropy) and contractility (negative inotropy), lowering blood pressure and cardiac workload.
- Common side effects include bradycardia, hypotension, fatigue, dizziness, and erectile dysfunction.
- Nonselective agents like propranolol can cause bronchospasm and are used cautiously in asthma/COPD; cardioselective agents (metoprolol, atenolol) are preferred in lung disease.
- They mask the early warning signs of hypoglycemia such as tachycardia and tremor, leaving sweating as the main remaining cue.
- Abrupt discontinuation can cause rebound hypertension, tachycardia, and angina or MI.
- Carvedilol and metoprolol succinate are used in stable chronic heart failure to improve long-term survival.
Nursing priorities
- Assess apical pulse for a full minute and blood pressure before each dose; hold and notify the provider if pulse is below 60 or systolic BP is below 90.
- Monitor for orthostatic hypotension and institute fall precautions.
- Monitor blood glucose closely in diabetic patients because hypoglycemia symptoms are masked.
- Taper the drug gradually rather than stopping abruptly.
- Assess respiratory status and lung sounds, especially in patients with reactive airway disease.
Labs & values
Patient teaching
- Take your own pulse daily and report a rate below 60 or feeling faint.
- Rise slowly from sitting or lying to prevent dizziness and falls.
- Do not stop the medication suddenly; refill before you run out.
Red flags: report now
- Apical pulse below 60 bpm or symptomatic bradycardia, new heart block, or systolic BP below 90 before a dose.
- Wheezing, dyspnea, or bronchospasm in a patient with asthma or COPD.
- Signs of worsening heart failure such as new crackles, weight gain, or peripheral edema.
- Never stop the drug abruptly because of rebound hypertension, ischemia, and MI risk.
References
Clinical references for this topic
