An elderly client is brought to the emergency department by ambulance following a syncopal episode at home. Once the client becomes alert, the emergency nurse gathers information about the client’s medical history and home medications. The client states that they think they accidentally took too many tablets of their terazosin today. They are supposed to take one tablet, but took five tablets because they look similar to another medication the client is prescribed. If one terazosin tablet is 5 mg, which total dose should the nurse tell the healthcare provider that the client took today? Round to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero. Any rounding should be completed at the end of the calculation. The answer must be numeric only. Do not add any units of measurement.

Alpha-1 adrenergic blockers: Nursing pharmacology

Last updated: January 27, 2022

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Definitions & Key takeaways

Alpha-1 blockers are a type of medication used to treat high blood pressure, prostate problems, and heart failure. By blocking the action of alpha-1 receptors in the body, these medications can help to lower blood pressure and improve symptoms related to benign prostatic hyperplasia (BPH), and heart failure. Examples of alpha-1 blockers include drugs like alfuzosin, doxazosin, and terazosin.

Chapters:

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Introduction0:00–0:25

Alpha-1 adrenergic blockers are medications that oppose the effects of the sympathetic nervous system, ultimately decreasing smooth muscle contraction.

Hence, these medications can be used to treat hypertension and benign prostate hyperplasia, and include prazosin, terazosin, and doxazosin, which are administered orally.Normally, the sympathetic nervous system triggers the fight or flight response by secreting catecholamines, which activate alpha-1 adrenergic receptors on the different organs.

Mechanism of action0:25–1:13

This results in smooth muscle contraction, in turn leading to an increase in the heart rate and blood pressure, as well as decreasing gastrointestinal motility and urination by contracting the sphincters.

So, once administered, alpha-1 adrenergic blockers bind and inhibit these alpha-1 adrenergic receptors. As a result, alpha-1 blockers cause vasodilation, which in turn decreases blood pressure.

In the urinary tract, they help relax the sphincters, which helps relieve the symptoms of benign prostate hyperplasia by decreasing the urine outflow obstruction.Now, since alpha-1 receptor inhibition causes vasodilation, common side effects include orthostatic hypotension and reflex tachycardia, especially after the first dose; as well as palpitations and edema.

Side effects1:13–1:55

Other side effects include anxiety, CNS depression, and blurred vision. Often, clients may also experience dizziness, headaches, and drowsiness, as well as nausea, diarrhea or constipation, urinary frequency, incontinence, and impotence.

Rarely, these medications may lead to priapism. Finally, clients taking doxazosin may develop arrhythmias or hepatitis.There are no major contraindications for alpha-1 blockers, but they must be used cautiously in pregnancy, breastfeeding, children, and elderly clients.

Contraindications and cautions1:55–2:27

In addition, prazosin and terazosin should be used with caution in clients with prostate cancer, and doxazosin in those with hepatic disease.

Finally, these medications may have dangerous interactions with vasodilators, beta blockers, and PDE5 inhibitors, potentially resulting in hypotension and syncope.Okay, if you’re caring for a client who has been prescribed the alpha-1 blocker prazosin for hypertension, begin by performing a baseline assessment of their weight and vital signs, as well as an orthostatic blood pressure assessment.

Nursing considerations & Client Education2:27–4:09

Moving on to client education, explain to your client how their medication helps control their blood pressure. Instruct them to take their medication with or without food; and emphasize the importance of taking it consistently and to not abruptly stop taking their medication, since rebound hypertension can occur.

Advise them to take their first dose at bedtime to avoid severe orthostatic hypotension and syncope that can occur with the initial dose.

Remind them that orthostatic hypotension can occur throughout treatment, so they should sit down if dizziness occurs, and always make position changes slowly.

Prompt them to contact their healthcare provider if hypotension and dizziness persist.Then teach your client to avoid alcohol while being treated with this medication, and to check with their healthcare provider before taking any over the counter medications.

Teach them how to take their blood pressure at home and explain the desired blood pressure values as well as those that require medical attention.

Lastly, reinforce lifestyle modifications to promote cardiovascular health, including maintaining a healthy weight, smoking cessation, reducing their sodium intake and increasing physical activity as tolerated.

Finally, when caring for a client taking an alpha-1 adrenergic blocker like prazosin, periodically monitor your client for side effects and evaluate for the therapeutic response of blood pressure control.All right, as a quick recap ….

Review4:09–4:58

Alpha-1 adrenergic blockers are a group of medications that oppose the effects of the sympathetic nervous system, decreasing smooth muscle contraction, and include prazosin, terazosin, and doxazosin.

They work to treat hypertension by causing vasodilation, and reduce the symptoms of benign prostate hyperplasia by relaxing the sphincters in the urinary tract.

Common side effects include orthostatic hypotension and reflex tachycardia. Nursing considerations when caring for a client who has been prescribed an alpha-1 blocker include performing a baseline assessment, monitoring for side effects, and evaluating the effectiveness of therapy.

Client education is focused on safe self-administration, and learning to recognize side effects that should be reported

ALPHA-1 BLOCKERS
DRUG NAME	prazosin (Minipress), terazosin, doxazosin (Cardura)
CLASS	Peripheral adrenergic antagonists α1 selective adrenergic blockers
MECHANISM of ACTION	Block peripheral α1-adrenergic receptors → dilates peripheral blood vessels → lowers peripheral resistance → reduces blood pressure
INDICATIONS	Hypertension Benign prostate hyperplasia (to decrease urine outflow obstruction)
ROUTE(S) of ADMINISTRATION	PO
SIDE EFFECTS	Dizziness, headache, and drowsiness Anxiety, CNS depression Palpitations, orthostatic hypotension, reflex tachycardia, and edema Blurred vision Dry mouth Nausea, diarrhea, and constipation Urinary frequency, incontinence, impotence, and priapism Doxazosin: arrhythmias and hepatitis
CONTRAINDICATIONS & CAUTIONS	Pregnancy and breastfeeding Children and elderly clients Prazosin and Terazosin: prostate cancer Doxazosin: hepatic disease Drug interactions: vasodilators, beta blockers, and PDE5 inhibitors
NURSING CONSIDERATIONS	Assessment and monitoring Assessment Weight, vital signs, orthostatic blood pressure Monitoring Side effects Evaluate for the therapeutic response: blood pressure control Client education Purpose of medication: blood pressure control Take with or without food Take consistently; do not abruptly stop medication to avoid rebound hypertension Take first dose at bedtime to avoid severe orthostatic hypotension and syncope Continue to make position changes slowly, sit down if dizziness occur Contact healthcare provider if hypotension and dizziness persist Avoid alcohol Check with healthcare provider before taking over-the-counter medications Blood pressure self-monitoring technique Desired blood pressure; readings that require medical attention Lifestyle modifications: maintaining a healthy weight, smoking cessation, reducing their intake of sodium, increasing physical activity as tolerated