Metoprolol Nursing Considerations

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Metoprolol Nursing Implications

Metoprolol Nursing Pharmacology Guide and Care Plan

Metoprolol is a beta-blocker mainly prescribed to manage hypertension, or high blood pressure, which should be maintained within a certain level to prevent a variety of health problems such as stroke, heart attack, and organ damage.

Other uses of Metoprolol are to treat angina (chest pain) and support heart health for post-myocardial infarction patients. Off-label uses for the drug include treatment for migraine, cardiac arrhythmias, and essential tremors.

Metoprolol is also used during the initial phase of myocardial infarction to improve the patient’s chances for survival. As with most cardiac drugs, Metoprolol can only be taken with a doctor’s prescription, and there are a number of considerations to be taken note of before a patient can take this drug.

Indications of Metoprolol

Metoprolol is commonly given either in its oral form as an immediate or extended-release tablet, or as an intravenous injection. The prescribed form and dosage will depend on the patient’s indication for the drug. Initial dose starts at 100 mg orally per day, either in a single or divided doses.

Dosage for maintenance use can range from 100 to 450 mg per day. A daily dose past 450 mg is not recommended, as there have been no studies conducted on its effectiveness yet.

Depending on the patient’s needs and response to the drug, a higher dose of Metoprolol may be needed than a low once per day dose to maintain drug efficacy within a 24-hour period.

Available forms of Metoprolol include the following:

  • Immediate release tablet: 25 mg, 37.5 mg, 50 mg, 75 mg,100 mg tablets
  • Extended release tablet: 25 mg, 50 mg, 100 mg, 200 mg tablets
  • Extended release capsule: 25mg, 50 mg, 100 mg, 200 mg capsules
  • Solution for injection: 1 mg/mL ampule

Indications and recommended dosage for Metoprolol are as follows:

  1. Hypertension: Recommended dose is 50 mg  per orem twice daily or 100 mg/day per orem in divided doses for adults. May be given with other anti-hypertensive medications to further decrease blood pressure as necessary.
  2. Hypertension in pediatric patients: For children ages 6-17 years old, initial dose is given at 1 mg/kg per orem once daily, up to 50 mg once daily. The dosage can be gradually increased for succeeding doses, up to 2mg/kg (200 mg) once daily as needed. Use only extended release tablets for pediatric patients. Use of metoprolol has not been approved for children younger than 6 years old.
  3. Myocardial infarction: 5mg via IV bolus dose every 2 minutes for 3 doses can be given as early treatment, followed by a 50 mg tablet 15 minutes after the third IV dose, then every 6 hours for 48 hours. If the patient is unable to tolerate the initial IV bolus dose, they may be given half of the recommended oral dose. Using metoprolol as treatment for MI should ideally be done within 12 hours of chest pain onset.
  4. The patient can then be prescribed a maintenance dose of 50-100 mg twice daily for up to three years.
  5.  Heart failure  (NYHA class II or III): Patients are prescribed 25 mg per orem daily dose for two weeks for class II heart failure, while class III patients are given 12.5 mg per orem daily for class III.
  6. Angina pectoris: 100 mg per orem daily, either as in single or divided doses. This dosage can be increased weekly, up to a maximum of 400 mg/day.
  7. Migraine prevention: 25-100 mg per orem dosing twice daily.
  8. Atrial fibrillation or flutter without accessory pathway: 25-100 mg per orem dose twice daily. For acute arrhythmias, 2.5-5 mg IV bolus dose to be given over 2 minutes for up to 3 doses. After the initial treatment with metoprolol IV, the oral form of the drug can be used as continuing treatment and should be initiated in 4-6 hours, with the initial oral dose not exceeding 50 mg twice daily.

Pharmacology of Metoprolol

  1. Mechanism of Action

Metoprolol is a form of the drug metoprolol, a cardioselective beta-blocker that selectively blocks beta-1-receptors but without blocking beta-2 receptors in doses less than 100 mg, making patients less likely to have side effects typically associated with beta-2 receptor inhibition. This selective inhibition leads to negative chronotropic (lower heart rate) and inotropic effects (lower heart contractility) with little to no effect in the lungs, gastrointestinal or urinary systems. This selective beta blocker inhibition is lost however at higher doses.

  1. Pharmacokinetics

  • In its oral form, most of the Metoprolol’s dose is readily and rapidly absorbed by the GI tract to be metabolized by the liver using the enzymes CYP2D6 and CYP3A4. After hepatic metabolism, about 50% of the administered dose is left to be distributed by the systemic circulation, 10% of which binds to serum albumin.  A following dose can increase systemic availability of the drug to approximately 70% for oral doses. Taking the oral form with food can also increase the systemic availability of the drug to around 30–40%.
  • For immediate release tablets, peak plasma levels are usually reached in about 3 hours. Drug half-life is 3-4 hours for non-extended release tablets. For patients with poor hepatic metabolism, half-life can go for up to 7 hours, with extremes ranging up to 9 hours.
  • In IV bolus form, drug effect onset happens immediately after administration, peaks at about 20 minutes, and lasts for 6-8 hours.  Plasma levels are usually twice as much as levels attained by oral concentrations.
  • The volume of distribution for metoprolol can range from 3.2 to 5.6 L/kg. It can cross the placental barrier and can be found in a lactating patient’s breast milk. It can also cross the blood-brain barrier, with drug levels in the cerebrospinal fluid coming close to the levels detected in the blood.
  • Metoprolol in the bloodstream is eliminated by the liver and excreted in the urine, where approximately 95 % of the drug can be found for oral users with good hepatic metabolism, and less than 10 % if the drug was administered intravenously. For patients with poor hepatic function, detectable amounts of metoprolol in the urine can reach 30-40 % whether taken orally or intravenously.

Side Effects of Metoprolol

Metoprolol Dosing Considerations

  • For known renal impairment patients: no dosage adjustment is needed, patients with renal failure were found to not have significantly different systemic availability or half-life duration of metoprolol compared to patients with normal renal function.
  • For patients with known liver impairment, consider lowering the dosage or taking an extended-release form of the drug, as liver impairment greatly affects the body’s ability to metabolize metoprolol, resulting in a prolonged drug half-life.
  • For patients with heart problems, consider lowering prescribed dose if the patient experiences a lower heart rate (bradycardia). If the patient’s heart failure symptoms appear to be worsening, consider temporarily withholding or lowering metoprolol dosage, or treat in conjunction with diuretics.
  • Geriatric patients should preferably be given lower doses of the drug when used to manage hypertension.
  • If using immediate-release tablets then switching to extended-release, use the same total daily dose initially prescribed for immediate release.
  • When changing between oral and IV drug forms, an equivalent desired effect of the drug can be achieved if given at a ratio of 2.5:1 oral-to-IV drug ratio.

Drug Interactions with Metoprolol

  • Metoprolol and insulin, oral hypoglycemic agents (OHA): Metoprolol has been found to increase or decrease the hypoglycemic effects of insulin, prolong hypoglycemia by interfering with glycogenolysis, or inhibit insulin secretion.
  • Metoprolol and antihistamines: Some antihistamines can cause increased metoprolol levels in the blood by affecting enzyme CYP2D6 metabolism, the hepatic enzyme primarily responsible for metoprolol elimination.
  • Metoprolol and salicylates, NSAIDs: Taking metoprolol with salicylates or other NSAIDs may decrease metoprolol’s antihypertensive effect due to inhibition of renal prostaglandins, leading to decreased renal blood flow and increased salt and water retention.
  • Metoprolol and barbiturates: decreased metoprolol levels. Excretion of certain types of barbiturates may be decreased by metoprolol, and lead to increased serum levels.
  • Metoprolol and cardiac drugs: Taking metoprolol with cardiac arrhythmia drugs can lead to amplified heart rate lowering effects. For some cardiac drugs, they can be used in conjunction with metoprolol to further lower the heart rate, but under a doctor’s close supervision.
  • Metoprolol and monoamine oxidase inhibitors (MAOIs): Taking metoprolol with MAOIs can increase the former’s effects on the heart and blood pressure, causing headaches and slowing the heart rate. MAOIs and metoprolol can continue interacting with each other for as long as 14 days after taking them together.
  • Metoprolol and benzodiazepines: Metoprolol can cause increased effects in benzodiazepines by decreasing metabolism of some types of the drug. However, the effect is oftentimes not clinically significant enough to stop taking these drugs together if needed.
  • Metoprolol and adrenergic agonists: Giving metoprolol in conjunction with adrenergic agonists can cause an increase in blood pressure and bradycardia, although the risk is lesser compared to combining the latter with non-specific beta-blockers.
  • Metoprolol and antibiotics, antivirals: Some antivirals, antibacterials, antifungals and anti-malarial drugs are metabolized by the body the same way as metoprolol, leading to potentially increasing the levels of the latter drug in the body.
  • Metoprolol and food: Taking metoprolol with food increases the amount of the drug absorbed in the bloodstream.
  • Metoprolol and alcohol: Taking metoprolol with alcohol may cause or increase experiences of blurred vision, drowsiness, dizziness, lightheadedness, or loss of consciousness.

Nursing Considerations for Metoprolol

  • Obtain the patient’s baseline values for laboratory tests such as CBC, blood glucose, and blood tests to check liver (SGPT/ALT, AST/SGOT) and kidney function (BUN, Creatinine). Close attention is paid to the liver, as it is the organ mainly responsible for metabolizing and eliminating the drug from the body, which is excreted by the urine.
  • Metoprolol is best taken during or after meals to improve digestion and drug absorption. Instruct the patient that extended-release tablets should be swallowed whole and not be crushed, chewed, or cut, unless the tablet is scored.
  • Abrupt withdrawal of the drug may cause myocardial infarction, ventricular dysrhythmias, and ischemia. Taper the dosage down over the course of 1-2 weeks.
  • Monitor blood pressure during the initial treatment, then periodically along with pulse rate every 4 hours. Always take the apical pulse and blood pressure before taking the drug. Notify the doctor if there is a significant change in blood pressure.
  • Since metoprolol can mask some of the symptoms of hyperthyroidism, particularly elevated heart rate, the patient should be monitored for signs of thyrotoxicosis. Advise the patient that abrupt withdrawal of the drug can possibly cause a thyroid storm.
  • For pregnant or lactating mothers, use only if benefits outweigh the risks, as the drug can enter the placental barrier and can be found in breast milk.
  • Abrupt withdrawal of the drug may cause myocardial infarction, ventricular dysrhythmias, and ischemia. Taper the dosage down over the course of 1-2 weeks.
  • Advise the patient to not use over-the-counter medications containing drugs that are known to have drug-drug interactions with metoprolol, such as nasal decongestants and cough remedies.
  • Advise the patient to report signs of adverse effects, such as an undesired decrease in heart rate, dizziness, confusion, fever, depression, sore throat and shortness of breath, and difficulty of breathing. Advise the patient to use artificial tears for dry eyes and to report any visual changes.
  • For diabetic patients taking metoprolol, blood sugar should be monitored regularly to ensure adequate glycemic control, as drug interactions with OHAs and insulin can increase or decrease hypoglycemic effects, mask some manifestations of hyperglycemia, such as heart rate changes, and can prolong hypoglycemic episodes.
  • Keep the patient’s extremities away from exposure to cold. Monitor the patient for signs of Raynaud’s disease, such as cold, painful, or tender feet or hands.
  • Overdose of metoprolol can lead to poisoning, which can manifest from 20 minutes to two hours after administration of the drug. Symptoms for metoprolol toxicity include severe hypotension, decreased heart rate, nausea, vomiting, hypoglycemia, hypokalemia, cardiac dysrhythmia such as AV block, cardiogenic shock, heart failure, cardiac arrest, bronchospasm, decreased level of consciousness. In case of a metoprolol overdose, interventions include lavage and administration of anticholinergics to counter bradycardia, administering bronchodilators for bronchospasm, and inotropic agents for heart failure.

Nursing Care Plan for Metoprolol

Possible Nursing Diagnoses

Nursing Assessment

Metoprolol Nursing InterventionsRationale
Assess the patient for signs and symptoms of hypertension, angina, arrhythmia, tachycardia, or other cardiac symptoms.To confirm the indication for administering Metoprolol.
Assess if the patient has COPD, Raynaud’s disease, AV block, hypotension, or sinus bradychardia.Metoprolol generally contraindicated in patients with asthma and chronic obstructive pulmonary disease (COPD) because they can cause bronchospasm. They should be avoided in patients with Raynaud’s disease due to the risk of exacerbation. Because beta blockers like Metoprolol reduce heart rate and exercise capacity, they are also contraindicated for patients with sinus bradycardia, partial and high degree AV block.
Check the patient’s allergy status.Previous allergic reaction to beta-blockers like Metoprolol may render the patient unable to take them. Alternatives to Metoprolol should therefore be considered in case of allergy.
Assess if the patient is pregnant or lactating.Metoprolol should be prescribed in caution to a pregnant woman as these drugs can potentially decrease placental perfusion.
Perform a focused physical assessment on the patient’s heart through and auscultation of heart sounds.To confirm the indication for administering Metoprolol.  
Assess the patient’s mucous membranes and his/her ability to swallow.To check for any potential problems with administration, hydration, and absorption.
To ensure that the right form of Metoprolol is given.
Collect blood sample for triglycerides and blood glucose levels.Metoprolol should be used cautiously in patients with diabetes.

Nursing Planning and Intervention

Metoprolol Nursing InterventionsRationale
Administer Metoprolol ideally with meals and/or at bedtime.To ensure optimal absorption and therapeutic action by Metoprolol, as well as reduce possible side effects.
Administer Metoprolol about 1 hour before or 2 hours after administering other oral medications, as prescribed.Ideal spacing of Metoprolol and other oral medications will ensure adequate absorption of the drugs administered.  
Educate the patient about the action, indication, common side effects, and adverse reactions to note when taking beta-blockers like Metoprolol. Instruct the patient on how to self-administer Metoprolol.To inform the patient on the basics of beta-blockers like Metoprolol, as well as to empower him/her to safely self-administer the medication.
Monitor the patient’s input and output and commence stool chart.Metoprolol may cause diarrhea or constipation. Early detection of either side effect can help institute a bowel program and relieve them effectively.
Discourage intake of fish oil, grape juice, and orange juice with MetoprololFish oil can enhance hypotensive effect of beta blockers like Metoprolol. Grape juice and orange juice can affect the potency of the drugs.
Encourage tobacco smoking sensation and reduction of alcohol consumption.Tobacco smoking and alcohol can reduce the benefits of Metoprolol.
Encourage the patient to change position slowly.To prevent orthostatic hypotension.
Advise the patient not to break or crush the medications, unless it is safe to do so.Sustained release beta blocker tablets should not be broken or crushed as doing so may affect the potency of the drugs.

Nursing Evaluation

Metoprolol Nursing InterventionsRationale
Ask the patient to repeat the information about Metoprolol.To evaluate the effectiveness of health teaching on Metoprolol.
Monitor the patient’s triglycerides and blood glucose levels.To ensure that Metoprolol did not cause any electrolyte imbalance of renal dysfunction.  
Monitor the patient’s response to Metoprolol in terms of side effects, especially blood pressure and GI status.To check for any hypotension, bradycardia, or GI side effects, as well as to see if Metoprolol has been effective or should be shifted to other medications due to an allergic reaction, severe side effects, or adverse reactions.

Nursing References

Ackley, B. J., Ladwig, G. B., Makic, M. B., Martinez-Kratz, M. R., & Zanotti, M. (2020). Nursing diagnoses handbook: An evidence-based guide to planning care. St. Louis, MO: Elsevier.  Buy on Amazon

Gulanick, M., & Myers, J. L. (2022). Nursing care plans: Diagnoses, interventions, & outcomes. St. Louis, MO: Elsevier. Buy on Amazon

Ignatavicius, D. D., Workman, M. L., Rebar, C. R., & Heimgartner, N. M. (2018). Medical-surgical nursing: Concepts for interprofessional collaborative care. St. Louis, MO: Elsevier.  Buy on Amazon

Silvestri, L. A. (2020). Saunders comprehensive review for the NCLEX-RN examination. St. Louis, MO: Elsevier.  Buy on Amazon

Disclaimer:

Please follow your facilities guidelines, policies, and procedures.

The medical information on this site is provided as an information resource only and is not to be used or relied on for any diagnostic or treatment purposes.

This information is intended to be nursing education and should not be used as a substitute for professional diagnosis and treatment.

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