Wk 10 Diuretics & Nitrates

Cardiac Drugs

Diuretics & Nitrates

Overview

  • Focus on chapters 26, 28, and 34

  • Context: Cardiac Drugs, part of Henry Ford College NURS 116 curriculum.

Diuretics (Pg. 494)

  • Definition: Diuretics are medications that promote water excretion, primarily used for managing fluid overload.

    • Application: Often combined with other blood pressure medications for better control.

    • Administration Routes: Available in oral (PO) or intravenous (IV) forms.

Types of Diuretics

  • Thiazide Diuretics (Pg. 494 & 635)

  • Loop Diuretics (Pg. 631)

  • Potassium-Sparing Diuretics (Pg. 637)

Thiazide Diuretics

  • Notable Example: Hydrochlorothiazide (HCTZ)

    • Description: This is the drug of choice for managing hypertension.

    • Administration Routes: Can be given PO or IV.

    • Specific Product Info: NOC 16729-183-17, Hydrochlorothiazide Tablets USP 25 mg.

Mechanism of Action

  • Inhibits reabsorption: Primarily of sodium (Na+) and chloride (Cl-).

  • **Effects:

    • Increases secretion of sodium and water.

    • Decreases plasma volume.

    • Leads to decreased preload and workload of the heart.

    • Results in reduced blood pressure.

Clinical Uses

  • Primary Uses:

    • Blood pressure management.

    • Managing fluid retention (edema), particularly in patients with heart failure.

Adverse Effects

  • Common Side Effects:

    • Low blood pressure (hypotension), particularly with potassium and sodium imbalances.

    • Electrolyte Imbalances: More pronounced in patients with existing kidney issues or when combined with ototoxic drugs.

  • Potential Drug Interactions:

    • Increased effects with NSAIDs.

    • Decreased effects observed with certain other medications.

Nursing Implications

  • Monitoring:

    • Check blood pressure and electrolytes (specifically potassium and sodium).

    • Be alert for signs of dehydration and hypotension.

    • Precautions:

    • Caution in patients with a sulfa allergy or during pregnancy.

Loop Diuretics (Pg. 631)

Overview

  • Function: These diuretics inhibit sodium (Na+) and chloride (Cl-) reabsorption in the loop of Henle, leading to significant diuresis.

Notable Example

  • Furosemide (Lasix):

    • Characteristics: This is the diuretic of choice for situations requiring rapid diuresis.

    • Indications: Particularly useful when kidney function is impaired, but must ensure that the patient is able to produce urine for efficacy.

    • Administration: Available in oral (PO) and IV forms, dosing can be titrated for maximum effect.

Clinical Uses

  • Common Applications:

    • Management of pulmonary and hepatic edema.

    • Treatment for heart failure.

    • Renal disease and hypertension management.

Adverse Effects

  • Potential Side Effects:

    • Electrolyte imbalances (especially sodium and potassium);

    • Dehydration;

    • Ototoxicity;

    • Hypotension, particularly in patients with low urine output (a contraindication).

Nursing Implications

  • Monitoring Pre-Administration: Check BP, labs (Na, K, BUN/Creat), and glucose (if diabetic).

  • Post-Administration Monitoring:

    • Monitor blood pressure and input/output (I/O).

    • Observe for signs of fluid reduction (decreased edema, clearer lung sounds).

    • Watch for adverse effects, including electrolyte disturbances and dehydration signs:

    • Signs of dehydration: Skin turgor, tachycardia.

    • Drug Interactions:

    • Increased effects with ibuprofen and phenytoin; decreased effects with corticosteroids and digoxin.

Potassium-Sparing Diuretics (Pg. 637)

Overview

  • Mechanism: These diuretics block aldosterone, which promotes water and sodium excretion while retaining potassium.

    • Notable Example: Spironolactone (Aldactone), often combined with loop diuretics to reduce potassium loss, allowing lower dosages of loop diuretics to be effective.

    • Administration Route: Given PO; maximum effect may take up to 6 weeks.

Clinical Uses

  • Primary Indications:

    • Heart failure.

    • Ascites.

    • Hypokalemia.

    • Hypertension.

    • Hyperaldosteronism.

Adverse Effects

  • Common Side Effects:

    • Dizziness.

    • Headache (HA).

    • Abdominal cramping.

    • Diarrhea.

    • Increased serum potassium levels.

Black Box Warning

  • Cautions: Can potentially cause tumor growth; use should be avoided in:

    • Patients with abnormal kidney function.

    • During the first trimester of pregnancy.

Nursing Implications

  • Administration Guidelines:

    • Administer at the same time each day, ideally in the morning, and may be taken with food to minimize gastrointestinal (GI) issues.

    • Patients should continue taking even if asymptomatic.

  • Monitoring Requirements: Check blood pressure, electrolytes, BUN/creatinine pre-admin, and observe for signs of dehydration and electrolyte imbalance. Assess for drug and food interactions, such as lithium and digoxin potentially reaching toxic levels, and herb interactions that could increase effects (e.g., ginger, licorice).

  • Drug Interactions:

    • Increased effects with ACE inhibitors, angiotensin receptor blockers (ARBs), potassium-containing drugs, and beta blockers.

    • Decreased effects seen with alcohol (ETOH), vasodilators, and salicylates.

Organic Nitrates (Pg. 524)

Overview

  • Function: Organic nitrates cause vasodilation, opening coronary arteries to improve heart perfusion while decreasing heart workload through effects on preload and afterload.

Angina

  • Definition: Characterized by lack of perfusion and oxygenation to the heart, leading to pain that may present with other symptoms.

Treatment for Angina

  • Medications Include:

    • Organic nitrates.

    • Calcium channel blockers.

    • Beta blockers.

Common Organic Nitrates

  • Examples:

    • Nitroglycerin, Isosorbide mononitrate, Isosorbide dinitrate.

    • Dosage Forms: Nitroglycerin available as sublingual tablets (0.4 mg each), available in brown bottles to protect from light exposure (to be replaced every 6 months).

    • Store at controlled temperatures, and avoid crushing sustained-release tablets.

    • Other forms include IV and topical transdermal applications (ointment).

Adverse Effects of Organic Nitrates

  • Common adverse effects include:

    • Severe headaches, often treated with acetaminophen.

    • Hypotension and orthostatic hypotension.

    • Bradycardia, dizziness, and possible syncope.

Contraindications

  • Notable Contraindications:

    • Concurrent use with erectile dysfunction medications.

    • Hypotension, severe anemia, hypovolemia, head injuries, and beta blockers.

    • Caution is advised in patients with abnormal kidney function.

Nursing Implications

  • Pre-Administration Checks: Requires checking blood pressure (hold if systolic < 90 or 30 mm Hg below the patient's normal), heart rate (hold if HR > 100), chest pain level, and the last time any erectile dysfunction medication was taken.

  • Post-Administration: Reassess pain and blood pressure, monitor for any adverse effects.

  • Administration Specifics:

    • Sublingual: Keep in light-protective containers; assess for tingling under the tongue as an indicator of efficacy.

    • Oral: Should be taken after a nitrate-free interval overnight and prior to meals.

    • Ointment: Apply using measuring papers; IV use is restricted to ICU or step-down units.

Critical Thinking Exercises

1. Spironolactone Administration Scenario

  • Scenario: Assessing a client with heart failure for spironolactone administration with the following values:

    • Blood pressure: 94/42

    • Heart rate: 110

    • Potassium: 3.3

    • Sodium: 141

    • BUN: 15

    • Creatinine: 0.98

    • Potential Action: Which assessment value should trigger the nurse to hold the medication?

2. Nitroglycerin Administration Scenario

  • Question: What assessments should a nurse perform prior to administering nitroglycerin sublingually?

    • A. Blood pressure

    • B. Heart rate

    • C. Pain level

    • D. Medication history

    • E. Allergies

    • Format: Select all that apply.