Angina Pectoris and Antianginal Therapy

• Angina pectoris is chest pain resulting from an imbalance between myocardial oxygen supply and demand.

Types of Angina

• Stable angina occurs with exertion and is relieved by rest or nitroglycerin.
• Unstable angina occurs at rest and is a medical emergency.
• Prinzmetal (variant) angina is caused by coronary artery vasospasm.

Goals of Antianginal Therapy

• Improving blood delivery involves dilating blood vessels and decreasing the heart's workload.
• Therapy aims to reduce the frequency and severity of anginal attacks and prevent myocardial infarction.

Antianginal Agents: Lifespan Considerations

• Antianginal drugs are not typically used for coronary artery disease in children.
• Nitroglycerin is the most common nitrate used in pediatric cases, with doses based on age and weight.
• Adults should be educated on proper nitroglycerin administration, storage, and effectiveness.
• Lifestyle modifications, such as weight loss and smoking cessation, are important for adults to lower CAD risk.
• Antianginal use during pregnancy is not considered safe and is not recommended during lactation.
• Older adults are at higher risk of adverse effects and may require lower starting doses with adjustments based on response.

Safe Medication Administration: Nitroglycerin

• Sublingual/transbuccal nitroglycerin is a preferred route.
• Tablets should be placed under the tongue or in the buccal pouch, allowing them to dissolve without swallowing.
• For transdermal patches, remove the old patch before applying a new one to a clean area, and include a nitrate-free interval.
• For nitroglycerin paste, measure the dose using the provided applicator, apply ointment-side down to the skin, and cover with plastic wrap.
• A different formulation of nitroglycerin is used for anal fissure pain, applied with gloves or plastic wrap on the finger.

Common Adverse Effects

• Headache, dizziness, syncope are common CNS effects.
• Sweating, flushing, and pallor are common dermatological effects.
• Hypotension and tachycardia are common cardiovascular effects.
• Nausea, vomiting, and incontinence are common gastrointestinal effects.

Nitrates (Prototype: Nitroglycerin)

• Action: Relaxes vascular smooth muscle, causing venous and arterial dilation, reducing preload and afterload, thus decreasing myocardial oxygen demand.
• Vascular Effects: Dilates veins, arteries, and capillaries, increasing blood flow and lowering systemic blood pressure.
• Hemodynamic Effects: Vasodilation reduces preload and afterload, decreasing cardiac workload and oxygen demand.
• Contraindications: Allergy to nitrates, severe anemia, head trauma, or cerebral hemorrhage.
• Adverse Effects: Headache, hypotension, dizziness, reflex tachycardia.
• Interactions:
  • Ergot derivatives may cause hypertension and reduce antianginal effects.
  • Phosphodiesterase type 5 inhibitors (sildenafil) can cause severe hypotension.
• Nursing Considerations: Tolerance may develop, and SL tablets should be stored in a dark glass container.

Nursing Considerations for Nitrates

• Assess for contraindications such as allergies, impaired liver/kidney function, hypotension, or pregnancy.
• Assess pain onset, duration, intensity, and relief measures.
• Monitor neurological, respiratory, and cardiopulmonary status.
• Administer sublingual preparations under the tongue and advise patients not to swallow.
• Instruct patients to repeat sublingual doses every 5 minutes for a maximum of three doses and to seek emergency help if pain persists.
• Ensure long-acting preparations are administered with nitrate-free intervals.
• Taper the dose gradually (over 4 to 6 weeks) after long-term therapy.

Beta-Adrenergic Blockers (Prototype: Metoprolol)

• Action: Blocks beta-1 receptors, reducing heart rate, contractility, and oxygen demand.
• Uses: Chronic stable angina, post-MI protection.
• Contraindications: Bradycardia, heart block, cardiogenic shock.
• Adverse Effects: Bradycardia, hypotension, fatigue, bronchospasm.
• Interactions:
  • NSAIDs may reduce antihypertensive effect.
  • Epinephrine can cause an initial hypertensive spike followed by bradycardia.
  • Insulin can mask symptoms of hypoglycemia.
• Nursing Considerations: Do not stop abruptly and monitor heart rate and blood pressure.

Nursing Considerations for Beta-Blockers

• Assess for contraindications such as allergies, bradycardia, heart block, diabetes, thyroid disease, or COPD.
• Assess neurological, cardiac, and pulmonary status, monitor urine output, and review lab results.
• Do not stop these drugs abruptly after chronic therapy; instead, taper gradually if possible.

Calcium Channel Blockers (CCBs) (Prototype: Diltiazem/Amlodipine)

• Action: Blocks calcium influx into myocardial and arterial muscle, causing vasodilation, reducing heart rate and contractility.
• Uses: Variant (Prinzmetal) angina, chronic angina, hypertension.
• Contraindications: Allergy to calcium channel blockers, pregnancy, and lactation.
• Adverse Effects: Bradycardia, hypotension, peripheral edema, constipation.
• Interactions:
  • Diltiazem may increase cyclosporine levels.
• Nursing Considerations: Monitor heart rate and blood pressure and avoid grapefruit juice.

Nursing Considerations for Calcium Channel Blockers

• Assess for contraindications such as allergies, impaired liver/kidney function, heart block, and pregnancy.
• Assess skin, pain, cardiopulmonary status, and review lab results.
• Intervention: Monitor blood pressure, cardiac rhythm, and cardiac output closely while the drug is being titrated or the dose is being changed.

Nursing Implications

• Assess pain (location, duration, quality, triggers) and vital signs before and after administration.
• Monitor ECG for rhythm and ischemic changes.
• Educate patients to:
  • take SL nitroglycerin at the first sign of chest pain.
  • Repeat 1 tablet every 5 min (max 3 doses in 15 min) — call 911 if there is no relief.
  • Avoid alcohol, hot showers after nitrate use.
  • Avoid grapefruit juice with CCBs or Ranolazine.
  • Not stop beta-blockers abruptly.