Angina is chest discomfort from myocardial ischemia — oxygen demand exceeds oxygen supply.

• Demand rises with heart rate (the biggest factor), contractility, and wall tension (preload and afterload)
• Supply depends on coronary blood flow, which occurs mainly during diastole — a slower heart rate lengthens diastole and improves supply

Types

• Chronic stable angina — fixed plaque; predictable with exertion; relieved by rest or nitroglycerin
• Vasospastic (Prinzmetal) angina — coronary spasm, often at rest or at night; treated with CCBs and nitrates, not beta blockers
• Unstable angina / acute coronary syndrome — an emergency; antianginal drugs relieve symptoms but reperfusion and antithrombotic therapy treat the cause (see Coronary Artery Disease)

How each class works

Combination logic: nitrates cause reflex tachycardia; beta blockers prevent it. Beta blockers can increase ventricular size; nitrates reduce it. The two classes complement each other.

Current approach (2023 AHA/ACC chronic coronary disease guideline): every client with angina has sublingual nitroglycerin for acute attacks; a beta blocker or CCB is first-line for symptom prevention; long-acting nitrates or ranolazine are added or substituted if symptoms continue. Aspirin (or another antiplatelet), a high-intensity statin, BP control, and lifestyle changes reduce events — antianginal drugs relieve symptoms but do not by themselves prevent MI.

Beta blockers after MI: the 2023 chronic coronary disease guideline advises reassessing long-term beta blockers (beyond 1 year after MI) in clients with LVEF above 50% and no other indication such as angina, dysrhythmia, or hypertension — the prescriber decides.

Nitrates — contraindications

• PDE-5 inhibitors: sildenafil or vardenafil within 24 hours, tadalafil within 48 hours (avanafil about 12 hours per its label) → life-threatening hypotension. Ask every client with chest pain, including about drugs for erectile dysfunction or pulmonary hypertension
• Riociguat (soluble guanylate cyclase stimulator) — contraindicated with nitrates. Vericiguat is not recommended with PDE-5 inhibitors, and data with long-acting nitrates are limited
• Hypotension (commonly SBP < 90 mmHg or ≥ 30 mmHg below baseline), marked bradycardia (< 50/min) or tachycardia (> 100/min) in ACS
• Right ventricular infarction — preload-dependent; nitrates can cause severe hypotension
• Severe aortic stenosis, hypertrophic obstructive cardiomyopathy
• Raised intracranial pressure, head trauma (nitrates raise ICP); angle-closure glaucoma (caution)

Ranolazine — contraindications: liver cirrhosis; strong CYP3A4 inhibitors (ketoconazole, clarithromycin, ritonavir) or CYP3A inducers (rifampin, carbamazepine, phenytoin, St. John's wort). Caution with QT-prolonging drugs and kidney impairment.

Beta blockers and CCBs: see Adrenergic Blockers and Calcium Channel Blockers — avoid beta blockers alone in vasospastic angina and in cocaine-related chest pain.

Pregnancy and lactation: nitroglycerin is used in pregnancy when needed (also for uterine relaxation in obstetric emergencies). Ranolazine and ivabradine lack safety data or are harmful — avoid unless the prescriber decides otherwise.

Major interactions

• Nitrates + PDE-5 inhibitors, riociguat, alcohol, other antihypertensives → hypotension
• Ranolazine + moderate CYP3A4 inhibitors (diltiazem, verapamil, erythromycin, fluconazole, grapefruit) → dose limit (500 mg twice daily)
• Ranolazine raises simvastatin and lovastatin (dose limits), digoxin, and metformin (metformin dose limit with higher ranolazine doses); additive QT prolongation with sotalol, antipsychotics, macrolides
• Beta blockers + verapamil/diltiazem → bradycardia and heart block

Listed in priority order.

1. During an anginal attack
   • Stop activity; have the client sit or lie down (nitrates can cause fainting); assess pain (location, character, severity, radiation), vital signs, SpO₂; obtain a 12-lead ECG per protocol
   • Before nitroglycerin: check BP and HR; confirm no PDE-5 inhibitor use within the time limits; hold and notify for SBP < 90 mmHg (or ≥ 30 mmHg below baseline), HR < 50 or > 100/min, or suspected RV infarction
   • Give 0.4 mg sublingual; repeat every 5 minutes up to 3 doses if pain persists and BP allows; recheck BP before each dose. Oxygen only if SpO₂ < 90%
   • Pain that does not resolve, or angina at rest, is treated as ACS — escalate, do not keep repeating nitroglycerin
2. IV nitroglycerin — continuous ECG and BP; titrate per protocol; infusion pump; non-PVC tubing; watch for hypotension and headache
3. Long-acting nitrates
   • Keep a nitrate-free interval of about 10–12 hours daily; schedule patch removal (for example, apply in the morning, remove at bedtime)
   • Patch: clean, dry, hairless skin on the chest or upper arm; rotate sites; do not cut; remove before defibrillation or cardioversion and before MRI if the patch contains metal; wear gloves when handling ointment or patches
   • Ointment: measure on the dose paper, spread without rubbing, cover; remove the previous dose and clean the skin
4. Beta blockers and CCBs — apical pulse and BP before doses; hold per parameters (commonly HR < 60/min, SBP < 90 mmHg)
5. Ranolazine — baseline and follow-up ECG (QTc), kidney function (creatinine) at baseline and periodically in kidney impairment, and a review of interacting drugs
6. Record the frequency, triggers, and nitroglycerin use of anginal episodes — increasing frequency means unstable angina

• Sublingual nitroglycerin: at the first sign of chest pain, stop and sit down; place 1 tablet under the tongue and let it dissolve (do not chew or swallow) or spray once onto or under the tongue (do not inhale the spray). If the pain is not better or is worse 5 minutes after the first dose, call emergency services, then you may take a second dose while waiting; up to 3 doses 5 minutes apart
• Take a dose 5–10 minutes before activities that usually cause angina (e.g., climbing stairs, sex), if the prescriber approves
• Storage: keep tablets in the original dark glass bottle, tightly closed, away from heat, light, and moisture — not in a pill box, a car, or a shirt pocket against the body; check expiry dates and replace as advised. A tingling or burning feeling is not a reliable sign of potency
• Never take nitrates with sildenafil, vardenafil (within 24 hours), or tadalafil (within 48 hours); tell emergency staff about these drugs
• Headache is common at first; use acetaminophen (paracetamol) if allowed — do not skip doses to avoid it
• Rise slowly; avoid alcohol and hot showers right after a dose
• Long-acting nitrates: follow the schedule for the nitrate-free period — around-the-clock use makes them stop working
• Never stop beta blockers suddenly — rebound angina or heart attack
• Ranolazine: swallow whole; avoid grapefruit; tell all prescribers you take it; report fainting or palpitations
• Keep a symptom diary; report more frequent, longer, or rest angina at once
• Risk-factor control: smoking cessation, BP and diabetes control, lipid therapy, regular activity (cardiac rehabilitation), heart-healthy diet

• Angina = oxygen demand > supply; heart rate is the main demand driver
• Sublingual nitroglycerin 0.4 mg every 5 minutes × 3; call emergency services if pain is not better 5 minutes after the first dose
• Check BP before each nitroglycerin dose; hold for SBP < 90 mmHg, RV infarction, or PDE-5 inhibitor use
• PDE-5 inhibitors: no nitrates within 24 hours (sildenafil, vardenafil) or 48 hours (tadalafil)
• Headache is the most common nitrate effect; tolerance is prevented by a nitrate-free interval of about 10–12 hours
• Keep nitroglycerin tablets in the original dark glass bottle; sit down before taking
• Beta blockers are first-line for stable angina; CCBs and nitrates for vasospastic angina
• Ranolazine: QT prolongation, CYP3A4 interactions, not for acute attacks, contraindicated in cirrhosis
• Nitrates + beta blockers complement each other (beta blocker blocks reflex tachycardia)
• Remove nitrate patches before defibrillation