4.14 Beta-2 Antagonists

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Propranolol is a Beta-2 antagonist.

Mechanism of Action: Propranolol is a nonselective beta blocker because of its inhibition of both Beta-1 and Beta-2 receptors.

Indications: Propranolol is used to treat high blood pressure, angina, various heart dysrhythmias (to lower the heart rate), and essential tremors. It is also used after a myocardial infarction to reduce mortality by decreasing heart workload, and in migraine prevention.

Nursing Considerations: Nonselective beta blockers must be used cautiously with patients who have co-existing asthma or chronic obstructive pulmonary disease (COPD) because of the effects on Beta-2 receptors that could potentially cause bronchoconstriction. It can also mask symptoms of hypoglycemia in diabetics. Use with caution in patients with impaired hepatic or renal function. Give immediate-release (IR) formulations on an empty stomach. Do not crush extended-release (ER) formulations. Propranolol ER is not considered a simple milligram-for-milligram substitute for conventional propranolol. Check blood pressure and apical pulse before giving drug; withhold and notify prescriber if apical pulse is less than 60 beats per minute or systolic blood pressure is less than 100 mm Hg, unless other parameters are provided. During IV administration, monitor blood pressure, ECG, and heart rate frequently. The most serious adverse effects include bronchoconstriction, hypotension, bradycardia, and signs of worsening heart failure. Other adverse effects are similar to selective beta blockers like metoprolol. Black Box Warning: Abrupt withdrawal of this drug may cause exacerbation of angina or a myocardial infarction. To discontinue this drug, gradually reduce dosage over 1 to 2 weeks.

Patient Teaching & Education: Patients should be instructed to follow the medication dosing regimen.  Stopping medication therapy abruptly may cause life-threatening arrhythmias.  Patients should be instructed on how to self-assess pulse and blood pressure to evaluate medication effectiveness.  The medication may cause increased susceptibility to orthostatic blood pressure changes and increased sensitivity to cold.[1]

Now let’s take a closer look at the medication grid on propranolol in Table 4.14.[2]

Table 4.14 Propranolol Medication Grid

Class/Subclass
Prototype/Generic
Administration Considerations
Therapeutic Effects
Side/Adverse Effects
Beta-2 Antagonist Nonselective B-blocker: propranolol Contraindicated in patients with asthma, COPD, or bradycardia

Use cautiously in patients who have diabetes mellitus because drug masks some symptoms of hypoglycemia

Use with caution in patients with impaired hepatic or renal function

Give immediate release formulations on an empty stomach

Do not crush ER formulations

Check BP and apical pulse before giving drug; withhold and notify prescriber if apical pulse is less than 60 or systolic blood pressure is less than 100 unless other parameters are provided

During IV administration, monitor blood pressure, ECG, and heart rate frequently

Decrease blood pressure and heart rate

Prevent migraines

Manage tremors

Most serious:

-Bronchoconstriction

-Hypotension

-Bradycardia

-Worsening heart failure

Black Box Warning: Abrupt withdrawal of drug may cause exacerbation of angina or myocardial infarction. To discontinue drug, gradually reduce dosage over 1 to 2 weeks

Other adverse effects similar to metoprolol

 


  1. uCentral from Unbound Medicine. https://www.unboundmedicine.com/ucentral
  2. This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain.

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