Cardiovascular Medications Part II lecture notes

Cardiovascular Medications Part II: Pharmacotherapeutics Overview

Health Conditions Related to Cardiovascular Medications

  • Blood clots include the following serious conditions:

    • Myocardial infarction (MI)

    • Ischemic stroke

    • Deep vein thrombosis (DVT)

    • Pulmonary embolism (PE)

    • Venous thromboembolism (VTE)

  • Coronary artery disease and hyperlipidemia are characterized by high levels of:

    • Low-density lipoprotein (LDL) cholesterol (bad cholesterol)

    • Triglycerides

  • Angina pectoris refers to chest pain due to insufficient blood flow to the heart.

  • Cardiac dysrhythmias are defined as abnormal heart rates or rhythms.

Classification of Cardiovascular Medications

  • The key categories and corresponding treatment options include:

    • Antiplatelets

    • Parenteral Anticoagulants

    • Oral Anticoagulants

    • Thrombolytics

    • Anti-Hyperlipidemics

    • Anti-Angina therapy

    • Anti-Dysrhythmics

Overview of Blood Clots (Thrombus)

  • Blood clots, or thrombi, are critical medical conditions requiring urgent treatment, including:

    • Myocardial infarction (MI)

    • Ischemic stroke

    • Deep vein thrombosis (DVT)

    • Pulmonary embolism (PE)

    • Venous thromboembolism (VTE)

Coagulation and Its Abnormalities

  • Abnormalities in coagulation can lead to the formation of thrombi, resulting in:

    • Occlusion of blood vessels

    • Emboli, which are dislodged clots

Clotting Factors and Their Role

  • Components involved in clot formation:

    • Prothrombin: A precursor to thrombin.

    • Activated Platelets: Play an essential role in clot formation.

    • Thrombin: Converts fibrinogen into fibrin.

    • Fibrinogen (soluble): Transforms into insoluble fibrin to create a clot.

Mechanisms of Action (MOA) of Cardiovascular Drugs

  1. Antiplatelets: Decrease platelet aggregation.

  2. Anticoagulants: Alter coagulation pathways to decrease clotting ability and prolong clotting time, preventing clot formation.

  3. Thrombolytics: Dissolve or “lyse” existing clots.

  • Report: Any signs of bleeding.

Antiplatelets

  • Common Drugs:

    • Aspirin

    • Clopidogrel (Plavix)

    • Prasugrel (Effient)

  • Uses: Reduce the risk of stroke or myocardial infarction (MI).

  • MOA: Decrease platelet aggregation, preventing the clotting cascade's initiation.

  • Adverse Effects:

    • Gastrointestinal bleeding (e.g., dark stools, melena, coffee-ground emesis)

    • Abdominal pain

    • Increased bleeding tendencies

  • Nursing Considerations:

    • Hold before surgery

    • Avoid with low platelet counts or in cases of hemophilia.

  • Due to the increased risk of bleeding from decreased platelet aggregation, clopidogrel should be withheld 5 days before elective surgery to decrease the risk of hemorrhage during surgery.

Specifics on Clopidogrel

  • Mechanism: Prevents platelet aggregation by blocking adenosine diphosphate (ADP) receptors, making platelets less “sticky.”

  • Uses: Reduce risk of ischemic stroke or MI.

  • Contraindications:

    • Bleeding disorders (e.g., peptic ulcers, hemorrhagic stroke)

  • Monitoring: Notify healthcare providers of drug regimen prior to surgery; hold drug as needed.

  • Adverse Effects:

    • Bleeding

    • Thrombotic thrombocytopenic purpura (TTP); monitor for low platelet counts <100,000/mm³.

Notes on Anticoagulants

  • Mechanism: Modify the clotting cascade, inhibit certain clotting factors, and prolong clotting times.

  • Have no direct effect on a blood clot that is already formed.

  • Clinical Uses:

    • Stroke

    • Atrial fibrillation

    • MI

    • DVT

    • PE

    • Mechanical heart valves.

Laboratory Monitoring

  • Effective monitoring of anticoagulants is crucial, with particular emphasis on:

    • Prothrombin Time (PT/INR) [Warfarin]

    • Activated Partial Thromboplastin Time (aPTT) [heparin]

Heparin Overview

  • Mechanism: Heparin binds with antithrombin III to inactivate thrombin, therefore inhibiting fibrinogen's conversion to fibrin. Prolongs clotting time.

  • Administration: Requires intravenous (IV) route for treatment of thrombotic events like DVT and PE.

  • Therapeutic Monitoring:

    • Requires frequent aPTT monitoring; typical PTT ranges from 30 to 40 seconds; aim for 60-80 seconds on heparin.

    • Antidote for overdose: IV protamine sulfate,if PTT gets too long.

Heparin Adverse Effects

  • Monitoring for Bleeding: Look for signs such as hematuria, hemoptysis, melena, and bruising.

  • Heparin-Induced Thrombocytopenia (HIT): Monitor platelet levels closely; stop medication if <100,000/mm³. monitor CBC.

  • Nursing implications:

    • Observe for signs of bleeding (↓ BP, ↑ HR, ↑RR, ↓Hemoglobin, mental status changes) – Must stop med!

    • Assess for IV site reactions (pain, bruising, redness)

    • Monitor PTT, which should be 1.5 to 2.5 times the normal range for a therapeutic effect

    • Monitor platelet levels in Complete Blood Count (CBC) for HIT

    • Avoid other medications that increase risk of bleeding: NSAIDs, aspirin, warfarin, ginkgo, feverfew, garlic

    • If heparin is given subcutaneously (SQ), it is used to prevent thrombotic events

    • High-alert medication; requires another RN to check dosage.

    • Review coagulation lab values

    • Use soft bristle toothbrush and electric razor

    • Report any bleeding to healthcare provider

    • Avoid IM injections and unnecessary venipuncture

    • Place patients on fall precautions; avoid going barefoot

    • Instruct patient to avoid straining

    • Wear medical alert bracelets

    • Avoid injuries and high-risk activities

Enoxaparin (Low Molecular Weight Heparin derivative)

  • Administration: Subcutaneously (SQ), with considerations for patients to avoid rapid reversal or alternate anticoagulation.

  • Drugs:

    • Enoxaparin (Lovenox) SQ only

    • Dalteparin (Fragmin) SQ only

    • Tinzaparin (Innohep) SQ only

  • Uses: Prevents DVT, especially in hospitalized patients.

  • Nursing: need to monitor for thrombocytopenia, platelet count <100,000/mm3 (CBC)

  • Adverse effect: bleeding – can use protamine sulfate

  • Given subcutaneously (SQ) – rotate sites

  • Does not require frequent monitoring of PTT

  • Not interchangeable unit for unit with heparin

  • Avoid other medications that increase risk of bleeding: NSAIDs, aspirin, warfarin, ginkgo, feverfew, garlic

  • Contraindications of Enoxaparin:

    • Hypersensitivity (urticaria, anaphylaxis)

    • Active major bleeding (GI bleed)

    • History of HIT within past 100 days 

Warfarin (Coumadin) Overview

  • Administration Route: Oral only, taken exactly as prescribed.

  • Mechanism: Reduces vitamin K-dependent clotting factors, affecting PT/INR.

  • Uses: Atrial fibrillation, thromboembolic disorder, DVT prevention.

  • Therapeutic Monitoring: Regular PT and INR checks, targeting INR levels between 2.0 - 3.0.

    • Taken orally, so takes 3-5 days for full effect; initially on heparin and warfarin together; heparin is continued to prevent clots until PT/INR levels indicate therapeutic effect

    • Maintain consistent amount of vitamin K foods: leafy green vegetables – kale, spinach, collard green (do not increase or decrease); do not take vitamin K supplements

    • Alcohol can increase risk of bleeding

  • Adverse Effects: Report any bleeding or signs of overdose and the use of vitamin K as an antidote if INR gets too long.

    • Requires frequent monitoring of PT/INR (international normalized ratio)

    • PT should be 1.5 times the reference value. INR target is 2.0 to 3.0

    • If PT is > 2.5 times the reference value, or high INR, the person will have bleeding tendencies.

  • Nursing considerations:

    • Monitor PT-INR regularly—keep follow-up appointments

    • Take exactly as prescribed at the same time daily.

    • Adverse effect (report): bleeding, hematemesis, hemorrhage, melena

    • Bleeding precautions; antidote is Vitamin K for treatment of overdose

    • Avoid Aspirin, NSAIDs, ginkgo, feverfew, garlic

    • Potential drug interactions—there are many! Warfarin interacts with many antibiotics and antifungal medications & increase risk of bleeding.

    • Avoid in pregnancy or breastfeeding (Pregnancy D)

Vitamin K

  • Actions: facilitates the synthesis of blood coagulation factors

  • Uses: antidote for overdose of warfarin

  • Lab tests: PT/INR

  • Teaching: maintain consistency in diet; avoid significant changes in daily intake of vitamin K foods.

  • Foods rich in vitamin K: asparagus, broccoli, cabbage, lettuce, turnip greens, pork or beef liver, green tea, spinach, watercress, and tomatoes.

Newer Oral Anticoagulants (NOACs)

  • MOA: inhibit factor Xa, which prevents the conversion of prothrombin to thrombin

  • Drugs:

    • Rivaroxaban (Xarelto) PO

    • Apixaban (Eliquis) PO

    • Fondaparinux (Arixtra) SQ

      • Do not give for at least 6 hours after surgery

  • Uses: stroke prevention with atrial fibrillation, DVT, PE

  • Adverse effects: bleeding, hematemesis, hemorrhage, melena

  • Nursing considerations:

    • Avoid the use of NSAIDs

    • Does not require specific blood coagulation monitoring but still monitor CBC.

    • Black box warning: spinal hematomas if patient has an epidural catheter; avoid if recent spinal puncture.

  • Dabigatran

    • MOA: direct thrombin inhibitor, prevents conversion of fibrinogen to fibrin; decrease clot formation

    • Drug:

      • Dabigatran (Pradaxa), PO

    • Uses: stroke prevention with atrial fibrillation, DVT, PE

    • Adverse effects: bleeding, GI hemorrhage, GI ulcers

    • Nursing considerations:

      • Avoid the use of NSAIDs

      • Does NOT require specific blood coagulation monitoring but still monitor CBC.

      • Stop medication before surgery.

      • Do NOT give if renal impairment.

Overall anticoagulants nursing considerations

  • Review coagulation lab values

  • Avoid other medications that may promote bleeding (aspirin/NSAIDs, ginkgo biloba, garlic, feverfew)

  • Do not give if history of hemophilia (bleeding disorder)

  • Use soft bristle toothbrush (elastic) and electric razor

  • Report any bleeding to healthcare provider and document

  • Avoid IM injections and unnecessary venipuncture

  • Place patients on fall precautions; avoid going barefoot

  • Instruct patient to avoid straining

  • Wear medical alert bracelets

Thrombolytics Overview

  • Active Ingredient: Alteplase (t-PA) - tissue plasminogen activator.

  • Mechanism: Works to break down existing clots by creating plasmin from plasminogen, which can digest the thrombus.

  • Indications: Used for MI, stroke, PE, and DVT.

  • Drugs (IV infusion):

    • Alteplase (tPA, Activase) tissue plasminogen activator

    • Reteplase

    • Tenecteplase

    • Urokinase

    • Streptokinase

    • Anistreplase

  • If pain or swelling at the IV site, STOP, do NOT give med.

  • Before administering:

    • Review any contraindications

    • Vital signs, electrocardiogram (ECG), cardiac monitoring

    • Obtain baseline labs before giving

  • Contraindications:

    • Internal bleeding or hemorrhagic stroke

    • Severe uncontrolled hypertension (>180/110 mm Hg)

    • Pregnancy

  • ADVERSE effects:

    • Allergic reactions (rash or wheezing)

    • Internal bleeding

    • Cardiac dysrhythmias

    • Hypotension

  • Nursing Implications: Monitor vital signs, especially for signs of bleeding (hypotension, altered mental status).

Thrombolytic drugs: Nursing considerations

  • Monitor vital signs and assess for signs of bleeding (↓ BP, ↑ HR, ↑RR, ↓Hemoglobin)

  • Assess and report evidence of bleeding (insertion site, urinary catheter, incision) or hidden bleeding (altered mental status)

  • Monitor blood tests (hemoglobin, hematocrit, and platelets)

  • Avoid aspirin, NSAIDs, ginkgo, feverfew, garlic

  • Interactions, increase risk for bleeding:

    • Heparin, anticoagulants

    • Clopidogrel, NSAIDs

    • Herb: ginkgo, garlic, ginseng, green tea, feverfew

  • Labs:

    • Increase clotting times

    • May decrease hemoglobin and hematocrit

  • Monitor for therapeutic effects (restored circulation, stable vital signs, pain eliminated)

  • Monitor and report signs of excessive bleeding (hemorrhage)

    • Bleeding of gums while brushing teeth, unexplained nosebleeds, heavier menstrual bleeding, black or tarry stools (positive guaiac stool), bloody urine or sputum, abdominal/back pain, vomiting blood

  • Monitor for adverse effects

    • Shortness of breath, rash, itching, dysrhythmia (irregular heart rhythm), chest pain. Assess the patient’s vital signs. If adverse reactions present, STOP the infusion!

Herbal supplements to note with thrombolytics

  • Ginkgo biloba

    • Uses: improve memory (vasodilator; improves blood flow to the brain).

    • Has antiplatelet effects.

    • Side effects: increased risk of bleeding in patients taking NSAIDs, antiplatelets, anticoagulants.

  • Feverfew

    • Uses: known for anti-inflammatory properties and relieving migraines.

    • Possible increase in bleeding with aspirin and other NSAIDs

    • Do not use in those allergic to ragweed, chrysanthemums, and marigolds, esp. if they have never used it before

Cholesterol reducing agents

Anti-Hyperlipidemics and Cholesterol Management

  • Lipoproteins Overview: LDL is the harmful cholesterol, while HDL is considered beneficial cholesterol.

  • Medications:

    • HMG-CoA reductase inhibitors (HMGs, or statins)

    • Niacin (Nicotinic acid)

    • bile acid sequestrants

    • fibric acid derivatives (Fibrates)

    • Cholesterol absorption inhibitor

Statins (HMG-CoA Reductase Inhibitors)

  • MOA: Inhibit cholesterol production in the liver by blocking HMG-CoA reductase.

  • Common Statin Drugs: Atorvastatin (Lipitor), Simvastatin (Zocor), Rosuvastatin (Crestor).

  • Used to:

    • Lower LDL

    • Increase HDL

  • Adverse Effects:

    • Before administering:

      • Review any contraindications (liver disorder, alcohol abuse, pregnancy, breastfeeding)

      • Obtain baseline lipid panel (LDL), liver function tests, creatine phosphokinase (CPK/CK) level

    • Adverse effects:

      • Myalgias – generalized muscle pain – mild increases in CPK/CK levels

      • Myositis – muscle pain, inflammation – moderate increases in CPK/CK levels

      • Rhabdomyolysis – most severe myopathy – breakdown of muscle – very high CPK/CK levels, myoglobin, and dark urine – can be fatal!

      • Hepatotoxicity (elevated LFT) – dark urine, vomiting, jaundice

      • ALT reference range: 4 to 36 U/L

  • Nursing considerations:

  • Statins: most effective when taken at night in the evening

  • It takes 6 to 8 weeks to see a change in cholesterol (lipid) levels

    • Should see a decrease in LDL levels and increase in HDL

  • Liver function tests are monitored

  • CK levels in patients reporting muscle pains

  • Exercise and healthy diet rich in vegetables, fruits, fiber, fish, low saturated fat foods

    • Do NOT take with grapefruit – increased risk for rhabdomyolysis

    • Diet rich in vegetables, fruits, fiber, low fat foods

  • Contraindicated in pregnancy, breastfeeding, liver disorders (alcoholism), drug allergy

Niacin (Nicotinic Acid, Niaspan)

  • Vitamin B3

  • Lipid-lowering properties require much higher doses than when used as a vitamin.

  • Indications: Primarily for patients at risk for pancreatitis with elevated triglycerides.

  • MOA: thought to work in the liver and adipose tissue to inhibit the synthesis of triglycerides and VLDL, which can lower LDL.

  • Uses:

    • First choice for patients at risk of pancreatitis and have elevated triglycerides.

    • Lower LDL, triglycerides; raise HDL.

  • Drug to drug interaction:

    • Niacin and statins: myopathy could progress to rhabdomyolysis

  • Side effect:

    • Flushing of face and neck, lasting up to an hour (minimize flushing w/aspirin or NSAIDs 30 minutes prior), flushing typically lasts for 1-2 hours after taking. Nurses need to teach patients about this expected side effect.

    • Pruritus

    • GI distress (take with meals to avoid GI irritation)

  • Adverse effects:

    • Hepatotoxicity (elevated liver enzymes/liver tests, jaundice, clay-colored stools; dark urine), hyperglycemia, hyperuricemia, orthostatic hypotension

Bile Acid Sequestrants

  • Drug Examples: Colestipol, Cholestyramine, Colesevelam.

  • Mechanism: Bind bile acids in the GI tract, prompt the liver to synthesize more bile acids using cholesterol, leading to lower cholesterol levels.

  • Use: Lower LDL cholesterol

  • Side effects:

    • Constipation (need to increase fiber intake)

    • Heartburn, nausea, belching, bloating (disappear over time)

  • Nursing Implications:

    • Assess for GI distress, bowel habits, vitamin K deficiency; may need vitamin supplementation

    • May bind with other drugs (advise to take other meds 1 hour before or 6 hours after)

    • Powder forms must be taken with at least 4 to 6 ounces of liquids, fruit juices, or applesauce, mixed thoroughly, and never taken dry

Fibric Acid Derivatives (Fibrates)

  • Drugs:

    • Fenofibrate

    • Gemfibrozil

    • Fenofibric acid

  • MOA: activate lipase, which breaks down cholesterol

    • Suppresses the release of free fatty acids from adipose tissue

    • Inhibit the synthesis of triglycerides in liver

    • Increase secretion of cholesterol into bile

  • Uses:

    • Lower triglyceride levels; increase HDLs

  • Adverse effects:

    • GI: nausea, diarrhea, abdominal discomfort

    •  Increased risk of gallstones (right upper quadrant abdominal pain)

    • Increased risk of myopathy, rhabdomyolysis when combined with statins

    • Increased risk of bleeding when combined with warfarin

  • Warnings:

    • Contraindicated in gallbladder impairment, severe renal impairment, and liver disease

  • Drugs:

    • Gemfibrozil (Lopid)

    • Fenofibrate (Tricor)

    • Fenofibric acid

Cholesterol absorption inhibitor: Ezetimibe (Zetia)

  • MOA: Inhibiting dietary cholesterol absorption in the GI tract

  • Drug: ezetimibe (Zetia)

  • Lowers LDL levels

  • Increased risk of hepatotoxicity if combined with a statin

Herbal supplements to note for reducing cholesterol

  • Garlic:

    • Reduction of hyperlipidemia

    • Has antiplatelet effects

    • Can increase risk of bleeding in patients taking NSAIDs, antiplatelets, warfarin and heparin.

    • Side effects: bad breath and odor.

  • Red yeast extract:

    • Reduction of hyperlipidemia

    • Fermentation of a yeast on rice

    • Adverse effects: elevation of liver enzymes, muscle problems, and liver problems

Drugs for Angina Pectoris

  • Angina “Chest pain”

    • Chest pain from lack of oxygenated blood supply to the heart.

    • Need to:

      • Increase oxygen supply to heart

      • Decrease oxygen demand of heart

    • Treatment: Relief of chest pain

  • Drugs: Nitroglycerin (NTG)

    • MOA: Decreases preload and afterload; Dilate (widen) veins and arteries causing smooth muscle relaxation

    • Results: increases oxygen to heart, decreases oxygen demand

    • Uses:

      • Rapid-acting: First choice treatment for acute/immediate angina

      • Long-acting: prevention of angina

      • Can use both rapid and long-acting forms together

    • Rapid-acting forms

      • Used to treat acute anginal attacks.

      • Sublingual (SL), spray, intravenous (IV).

    • Long-acting forms

      • Used to prevent anginal attacks

      • PO (extended-release), transdermal

  • Side/Adverse effects: All Nitrates

    • Expected side effect for all forms of nitrates:

      • CNS – headaches (expected), Headaches can be managed with acetaminophen

    • Adverse effects for all forms of nitrates:

      • CV – hypotension; reflex tachycardia

    • Warnings:

      • Contraindicated: ED drugs: sildenafil, phosphodiesterase type 5 inhibitors

        • Can cause life-threatening hypotension

      • Contraindicated in patients with head trauma and intracranial bleeding

      • Careful when taking other medications that can decrease BP

      • Avoid alcohol while using.

Rapid-acting nitrates

  • Acute angina: use nitroglycerin sublingual (Nitrostat) or spray

    • Administration: place one sublingual (SL) nitroglycerin under the tongue every 5 minutes for a maximum dose of three (3) tablets

    • Tell patient, “if chest pain is unrelieved after 5 minutes of first dose, call 911 and take second dose”

    • Tell patient they will experience a tingling/burning feeling under their tongue

    • Keep in original airtight, dark glass bottle – away from light, heat, moisture

    • If using spray, release spray onto or under tongue (do not inhale spray)

    • Keep a fresh bottle of SL nitroglycerin, drug is stable for about 3 months

    • Sit or lie patient down and take medication to prevent orthostatic hypotension

    • May take one SL tablet before exercising to prevent angina

    • If acute chest pain, can take SL nitroglycerin when wearing nitro patch

Long-acting nitrates

  • Applying patches & ointment: (Nitro-Dur, Nitro-Bid, Transderm-Nitro)

    • To prevent occurrence of anginal attacks, not to manage an acute attack

    • Use a hairless area of upper arms or body, rotate sites

    • Tolerance develops with continuous use of transdermal patches/ointments. To decrease tolerance, remove at night to allow 8 to 12 hours without patch. “nitrate free period”

    • Apply once a day, wear for 12 hours; remove after wearing for 12 hours a day

    • Wear gloves to avoid getting ointment on hands (vasodilation, ↓BP)

    • Ointment: squeeze prescribed amount onto paper & apply to skin without rubbing. Tape paper in place using an occlusive covering.

  • Administration of oral tablets: Isosorbide mononitrate; isosorbide dinitrate

    • Oral (extended-release) to prevent future attacks, not to manage an acute attack

    • Do not crush or chew sustained release tablets

    • Do not withdraw drug abruptly; doing so may precipitate acute angina

    • Geriatric patients are more susceptible of postural hypotension (rise slowly)

  • Long-acting Nitrates: Patient teaching

    • Nitrates are not habit-forming, but tolerance may develop

    • Have a home monitor BP cuff; rise slowly

    • If patient has nitro patch and experiences sudden/acute chest pain, take SL nitro and monitor vital signs (BP and HR)

    • Be compliant with medication even if experience headaches

      • Nursing consideration: can give acetaminophen

    • If needs to discontinue, will need to do so slowly to prevent rebound angina

    • Remind patients that taking a long-acting NTG preparation should not keep them from using SL or spray nitroglycerin if sudden chest pain develops.

Antidysrhythmic Drugs Overview

  • Dysrhythmias Defined: Irregular heart rhythms affecting cardiac output.

  • Goals of Treatment: restore adequate cardiac output

Conduction system

  • Automaticity: ability to generate electrical impulse; SA node has a high degree of automaticity

  • Conductivity: ability of cardiac tissue to transmit electrical impulse; normal impulse: SA node to atria, then AV node to ventricle

  • After contraction (refractory): cannot respond to electrical stimulus.

Types of Dysrhythmias

  • Sinus: bradycardic or tachycardic; impulse originates in SA node. Only significant if severe or prolonged

  • Atrial: ectopic sites replace SA node as pacemaker

  • Ventricular: impulse forms in ventricles, most serious – need immediate attention.

Vaughan-Williams Classification of Antidysrhythmic drugs

  1. Class I (IA, IB, IC): Sodium channel blockers (e.g., Quinidine, Lidocaine).

  2. Class II: Beta-adrenergic blockers (e.g., Propranolol, Carvedilol).

  3. Class III: Potassium channel blockers (e.g., Amiodarone).

  4. Class IV: Calcium channel blockers (Verapamil, Diltiazem).

  5. Other

Class IA sodium channel blockers

  • Inhibit sodium channels in heart

  • Class IA: Quinidine, procainamide

  • Action: slow conduction and reduce automaticity

  • Used for atrial fibrillation

  • Nursing: Dosing: every 6 hours; It should be taken around-the-clock, so that a stable blood level of the drug can be maintained; do not take with grapefruit juice

  • Adverse/side effects:

    • Cinchonism (tinnitus, headache, nausea, vertigo), thrombocytopenia

    • Hypotension, high doses: QT prolongation, heart block

    • GI: Diarrhea (common)

Class IB Sodium channel blockers

  • Inhibit sodium channels in heart

  • Class IB: IV lidocaine, phenytoin

  • Action: decrease action potential duration, reduces automaticity

  • Use: ventricular dysrhythmias

  • Adverse effects: hypotension, bradycardia

  • CNS toxic effects: twitching, seizures (convulsions), confusion

  • Must continuously monitor BP and cardiac rhythm (ECG)

Class IC sodium channel blockers

  • Inhibit sodium channels (more pronounced effect)

  • Class IC: flecainide (Tambocor)

  • Action: decrease conduction

  • Use: ventricular dysrhythmias, atrial fibrillation

  • Adverse effects: visual disturbances, blurred vision, dyspnea, palpitations

  • Nursing: monitor apical pulse and BP

Class II Beta-Adrenergic blockers

  • MOA: block SNS stimulation, reducing transmission of impulses in conduction system

  • Class II: Propranolol, Labetalol, Carvedilol

  • Use: sinus tachycardia, cardiac dysrhythmias

  • Side effects: fatigue, sleep disturbances, impotence

  • Adverse effects: bradycardia, hypotension, heart block

  • Cautions:

    • If we block Beta 2 receptors, bronchoconstriction can occur

    • Diabetes mellitus – BBs slow down heart rate and mask signs of hypoglycemia

    • Abrupt withdrawal can cause rebound hypertension

Class III Potassium channel blockers

  • Slow repolarization/prolong refractory period

  • Class III: Amiodarone (Cordarone), Dronedarone (Multaq)

  • Use: ventricular dysrhythmias, ventricular tachycardia

  • Many possible adverse effects!

  • Adverse effects:

    • Pulmonary toxicity (dyspnea – shortness of breath, cough, fibrosis)

      • Require baseline chest x-ray and pulmonary function tests before administration, careful resp assessment

    • Thyroid dysfunction: hypothyroidism or hyperthyroidism

      • Need baseline thyroid panel before administration

    • Corneal deposits (visual halos, photosensitivity, photophobia, vision changes)

      • Need eye exams; report vision changes

      • Photosensitivity: need to wear protective clothing

    • Hepatotoxicity (elevated LFTs)

      • Need to avoid alcohol, monitor LFTs, liver failure

    • Dysrhythmias (monitor ECG, QT prolongation, electrolyte levels)

    • Hypotension, bradycardia (monitor BP & pulse closely)

    • Neurologic: abnormal gait, coordination problems

  • Adverse effects may last for weeks to months after stopping.

  • Patient teaching for amiodarone:

    • Report any respiratory symptoms

    • Check BP and pulse regularly

      • Report: bradycardia, hypotension, adverse effects

    • Monitor LFTs (If elevated, abnormal), thyroid function, ECG

    • Follow recommendation for regular ophthalmic exams

    • Use dark glasses to ease photophobia

    • Wear protective clothing and use sunscreen

    • Do not take with grapefruit juice

Class IV calcium channel blockers

  • Inhibit calcium-dependent pathways, reduce automaticity, slow conduction

  • Drugs: IV Verapamil, Diltiazem

  • Use: atrial dysrhythmias

  • Adverse effects: hypotension, bradycardia, heart block

  • Side effect: constipation (need to increase fiber)

  • Nursing considerations: monitor BP and pulse, ECG, bowel habits

Digoxin (Cardiac glycoside)

  • Drug: Digoxin; Class: cardiac glycoside

  • MOA: influx of Ca++ in cells

    • 1. Increasing myocardial contractility (+) inotropic

    • 2. Increase vagal activity: conduction slowed through AV node and refractory time
      (–) chronotropic: rate, (–) dromotropic: conduction

  • Uses:

    • Heart failure (second line due to toxicity)

    • Atrial fibrillation

  • Nursing considerations:

    • Take pulse for a full minute before administering

    • If apical pulse < 60, do not administer drug

    • Narrow therapeutic range: 0.5 to 2 ng/mL

    • Before administering:

      • Check lab tests and ECG – cardiac monitor, serum potassium level, kidney function

      • If serum potassium <3.5, do not administer, it can increase risk for digoxin toxicity

    • Symptoms of heart failure should improve

      • Less dyspnea, edema, crackles; monitor lung sounds

    • Fiber supplements may reduce absorption of digoxin

  • Digoxin toxicity

    • Toxicity:

      • Early: anorexia, nausea, vomiting, headache, bradycardia

      • Late: visual disturbances – blurred vision, yellow vision, visual halos around bright objects; muscle weakness, confusion

      • Teach clients symptoms of toxicity and report them immediately

    • Antidote:

      • Digoxin immune Fab (Digibind, Digifab)

    • Nursing:

      • Need to check acid-base and electrolyte balance (esp. hypokalemia – potassium <3.5)

      • Monitor pulse rate for at least 1 min, cardiac rhythm (ECG)

      • Verapamil and Diltiazem can raise digoxin levels, increase risk of digoxin toxicity

      • Symptoms of heart failure should improve

Other antidysrhythmic drugs

  • Drug: adenosine (Adenocard)

    • Use: converts paroxysmal supraventricular tachycardia to sinus rhythm

    • MOA:

      • Slows automaticity in SA node; slows conduction

      • Very short half-life (<10 seconds) – administer as a rapid IV bolus.

      • May cause asystole for a few seconds (be sure to have emergency cardiac resuscitation equipment available)

    • Nursing:

      • Need continuous cardiac monitoring

  • Drug: Magnesium sulfate

    • Uses: Torsade de Pointes (TdP) is a variant of ventricular tachycardia that can be the result of prolongation of the QT interval

    • Give magnesium to the patient in TdP

    • MOA: affects conduction of nerve impulses, muscle contraction, heart rhythm

    • Health conditions leading to low Mg++: malabsorption; alcoholism, loop diuretics

    • Indications: magnesium deficiency; short-term treatment of constipation; dysrhythmias.

    • Side effects (too much magnesium): diarrhea, lethargy, depression, increased reflexes

    • Monitor VS, cardiac rhythm.

Anti-Dysrhythmics: Nursing considerations

  • Monitor for dysrhythmias

  • Monitor VS (pulse and BP); avoid caffeine

  • Ensure patient knows to notify provider of any worsening of dysrhythmia or toxic effects:

    • Hypersensitivity reactions

    • Nausea/vomiting

    • Shortness of breath

    • Rapid weight gain

    • Chest pain

    • Many can lead to prolongation of QT interval