Antianginal Drugs: Generic and Brand Names
- Nitrates and Nitrites
- amyl nitrate (Vaporole)
- isosorbide mononitrate (Imdur, Monoket)
- isosorbide dinitrate (Isordil, Sorbitrate)
- nitroglycerin (Nitro-bid, Nitrostat)
- Beta-Adrenergic Blockers
- acebutolol (Sectral)
- esmolol (Brevibloc)
- metoprolol (Toprol, Toprol XL)
- nadolol (Corgard)
- propranolol (Inderal, Lopressor)
- timolol (Blocardren)
- Calcium-Channel Blockers
- amlodipine (Norvasc)
- diltiazem (Diltiazem, Diltiazem SR)
- nicardipine (Cardene)
- nifedipine (Adalat, Procardia)
- verapamil (Calan, Isoptin)
- Piperazineacetamides
- ranolazine (Ranexa)
- Non-Nitrate Coronary Vasodilators
- dipyridamole (Persantine)
Disease Spotlight: Coronary Artery Disease
Coronary artery disease (CAD) is the narrowing of the vessels supplying oxygen and nutrients to the heart, mostly from fatty deposits (atheromas) in the vessel lumen, a process called atherosclerosis. The process attracts platelets and clotting factors, building a larger obstruction, and the vessels lose their elasticity so they can no longer dilate and constrict normally. The heart calls for more blood, but the narrow vessels limit delivery, so the heart's oxygen supply drops and the hypoxia produces pain (angina). There are two types: classic angina (of exertion), from diminished coronary blood flow, and vasospastic (Prinzmetal's, variant) angina, from reversible vasospasm even at rest. Both cut the heart's oxygen supply.
Nitrates
Nitrates act fast, relaxing smooth muscle and depressing muscle tone without affecting nerve activity. They reduce preload and myocardial muscle tension by dilating the veins and reduce afterload by dilating the arteries, and both actions lower oxygen demand by cutting the heart's workload.
Therapeutic Action
The main effect is a drop in systemic blood pressure. The body compensates by increasing flow to healthy arteries and veins, since the affected vessels have already lost their elasticity.
Indications
In children, nitrates are used only for congenital heart defects and cardiac surgery, because they can cause dangerous blood pressure swings. Adults need teaching on the drug's forms and their proper administration, storage, effectiveness, and the signs that warrant prompt medical help, plus lifestyle changes (smoking cessation, low-fat diet, weight loss). Older adults need safety measures because they are prone to arrhythmias and hypotension, and they should start at a low dose because likely hepatic and renal impairment slows metabolism and excretion. Use in pregnancy is not established. Sublingual nitroglycerin is most effective for recurrent variant angina, and a continuous infusion or transdermal patch is used for unstable angina.
Pharmacokinetics
| Route | Onset | Duration |
|---|---|---|
| IV | 1-2 min | 3-5 min |
| Sublingual tablet | 1-3 min | 30-60 min |
| Translingual spray | 2 min | 30-60 min |
| Transmucosal tablet | 1-2 min | 3-5 min |
| Oral SR tablet | 20-45 min | 8-12 h |
| Topical Ointment | 30-60 min | 4-8 h |
| Transdermal | 30-60 min | 24 h |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| 1-4 min | liver | kidney (urine) |
Contraindications and Cautions
Allergy to nitrates, to prevent hypersensitivity. Severe anemia, since the drop in cardiac output is dangerous for blood with low oxygen-binding capacity. Head trauma and cerebral hemorrhage, since relaxing the cerebral vessels can drive intracranial bleeding. Pregnancy and lactation, for potential fetal harm. Hepatic and renal disease, which alter metabolism and excretion. Conditions that limit cardiac output (hypovolemia, hypotension).
Adverse Effects
- CNS: throbbing headache, dizziness, weakness
- GI: nausea, vomiting, incontinence
- CV: hypotension, reflex tachycardia, syncope
- EENT: pallor, flushing, sweating
- A large dose leads to methemoglobinemia and cyanosis.
Interactions
Ergot derivatives raise the risk of hypertension and decrease the antianginal effect. Heparin loses therapeutic effect with nitrates. PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) carry a risk of severe, potentially fatal hypotension, so nitrates are contraindicated within 24 to 48 hours of these drugs (StatPearls).
Nursing Management
Nursing Assessment
Check for the contraindications and cautions above. Inspect skin color and integrity, especially for transdermal or topical forms. Assess pain and activity level and neurologic status (level of consciousness, affect, reflexes). Take cardiopulmonary status, counting the heart rate for one full minute, and get an ECG as ordered along with labs (CBC, liver and kidney function tests).
Nursing Diagnoses
- Decreased cardiac output related to vasodilation and hypotensive effects of the drug
- Risk for injury related to adverse neurologic and cardiovascular effects
- Ineffective tissue perfusion related to low oxygen supply to myocardial cells
Implementation with Rationale
Tell the patient not to swallow sublingual preparations. Teach the current American Heart Association rule: take one tablet, and if chest pain has not improved or is worsening 5 minutes after that first dose, call 911 right away; while waiting, the patient may take up to two more tablets at 5-minute intervals for a total of three doses (American Heart Association). The older instruction to take all three doses before seeking help has been replaced, because failure to respond to the first dose can signal a heart attack. Ask about a burning sensation to confirm potency, and protect the drug from sunlight to maintain it. For sustained-release forms, take with water and do not crush, since they must reach the GI tract intact. Rotate injection sites and give skin care to prevent abrasion and breakdown. Never stop long-term therapy abruptly; taper over 4 to 6 weeks to prevent myocardial infarction. Provide comfort measures: small frequent meals, comfortable room temperature and lighting, noise reduction, ambulation help, reorientation, and skin care.
Evaluation
Monitor response through pain assessment, watch for the adverse effects above, check that comfort measures work, confirm compliance, and track labs.
Beta-Adrenergic Blockers
Beta-adrenergic blockers block the effects of sympathetic stimulation, which is why they are also called sympatholytics.
Therapeutic Action
They lower blood pressure, contractility, and heart rate by blocking beta-receptors in the heart and in the juxtaglomerular apparatus of the kidneys, and together those effects reduce the heart's oxygen demand. They are usually combined with nitrates because of reduced adverse effects and better exercise tolerance. They are not indicated for variant angina, because the therapeutic effect can trigger vasospasm.
Indications
Nadolol manages chronic angina and is the drug of choice in angina patients with hypertension. Propranolol is the prototype and is used for angina and syncope. Nebivolol, the newest agent, does not produce the same adverse effects as propranolol.
Pharmacokinetics
Food increases the bioavailability of propranolol. Propranolol is the only drug in this class that crosses the blood-brain barrier.
Contraindications and Cautions
Bradycardia, heart block, and cardiogenic shock, which the blocking effect worsens. Pregnancy and lactation, for potential harm to the fetus or neonate. Diabetes, COPD, thyrotoxicosis, and peripheral vascular disease, where the blocking effect prevents the body from meeting its homeostatic needs.
Adverse Effects
- CNS: emotional depression, dizziness, fatigue, sleep disturbances
- GI: gastric pain, nausea, vomiting, colitis, diarrhea
- CV: heart failure, reduced cardiac output, arrhythmia
- Respiratory: dyspnea, cough, bronchospasm
Interactions
Clonidine increases rebound hypertension. NSAIDs decrease the antihypertensive effect. Epinephrine causes hypertension followed by bradycardia. Ergot alkaloids cause peripheral ischemia. Insulin and oral hypoglycemics can shift blood glucose without the patient feeling the usual hypo- or hyperglycemia warning signs.
Nursing Considerations
Nursing Assessment
Check for the contraindications and cautions above. Assess neurologic status, focusing on orientation and sensory function, for CNS effects. Take blood pressure and count the heart rate for one full minute. Auscultate the lungs for respiratory effects. Check color, sensation, and capillary refill in the extremities for peripheral vascular insufficiency. Monitor labs (electrolytes, renal function) for arrhythmia risk and dose adjustment.
Nursing Diagnoses
- Decreased cardiac output related to decreased heart rate, blood pressure, and contractility
- Ineffective tissue perfusion related to decreased blood flow to the heart
- Risk for injury related to possible CNS alterations during therapy
Implementation with Rationale
Give the drug as ordered. Provide comfort measures: ambulation help, raised side rails, appropriate room light and temperature, and rest periods. Monitor cardiopulmonary status closely for changes in vital signs that signal a needed dose adjustment. Teach the patient not to stop therapy abruptly, since that can cause rebound hypertension and myocardial infarction.
Evaluation
Monitor response, watch for the adverse effects above, check that comfort measures work, confirm compliance, and track labs.
Calcium-Channel Blockers (CCBs)
Calcium-channel blockers inhibit the movement of calcium ions, altering arterial and cardiac muscle action potentials and blocking contraction. They produce vasodilation and relieve spasm, do not raise lipid levels, and substitute for classic and variant angina when beta-blockers and nitrates are contraindicated.
Therapeutic Action
By blocking contraction, they cause loss of muscle tone and vasodilation, dropping peripheral resistance. They relieve vasospasm in variant angina, increasing blood flow to the heart, and can block the atherosclerotic process in endothelial cells. They are indicated for variant angina, chronic angina, and effort-associated angina.
Pharmacokinetics
| Route | Onset | Peak | Duration |
|---|---|---|---|
| Oral | 30-60 min | 2-3 h | 2-4 h |
| SR, ER | 30-60 min | 6-11 h | Varies |
| IV | Immediate | 2-3 min | Varies |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| (3.5-6h); ER (6-7h) | liver | kidney (urine) |
Contraindications and Cautions
Allergy to the drug. Heart block and sick sinus syndrome, where the slow-conduction effect can worsen existing conduction problems. Renal and hepatic dysfunction, which alter metabolism and excretion. Heart failure, worsened by the drug's drop in cardiac output.
Adverse Effects
- CNS: dizziness, lightheadedness, fatigue, headache
- GI: nausea, hepatotoxicity
- CV: hypotension, bradycardia, peripheral edema
- EENT: flushing, rash
Interactions
Cyclosporine with diltiazem raises cyclosporine serum levels and toxicity. Cyclosporine with verapamil causes heart block and digoxin toxicity, and verapamil raises digoxin levels. Digoxin with verapamil depresses myocardial conduction. General anesthesia with verapamil causes serious respiratory distress.
Nursing Considerations
Nursing Assessment
Check for the contraindications and cautions above. Inspect skin color and integrity for adverse effects. Assess the patient's pain and activity level before and after pain onset to identify contributing factors and track progression. Monitor cardiopulmonary status closely, since the drug can hit both systems hard.
Nursing Diagnoses
- Decreased cardiac output related to hypotension and the vasodilating effect of the drug
- Risk for injury related to cardiovascular and CNS adverse effects
Implementation with Rationale
Monitor blood pressure and heart rate and rhythm for developing adverse effects. Provide comfort measures (small frequent meals for nausea, controlled noise, light, and temperature to limit stress that raises cardiac demand). Teach measures to avoid angina attacks (diet changes, rest periods). Stress strict adherence for maximum effect.
Evaluation
Monitor response, watch for the adverse effects above, check that comfort measures work, confirm compliance, and track labs.
Frequently Asked Questions
How do antianginal drugs relieve chest pain? They restore the balance between the heart's oxygen supply and demand. Nitrates dilate veins and arteries to cut preload and afterload, beta-blockers slow the heart and lower contractility, and calcium-channel blockers relax vessels and relieve spasm. Less work plus better flow means less ischemic pain.
What is the right way to take sublingual nitroglycerin for an angina attack? Sit down, place one tablet under the tongue, and let it dissolve. If the pain has not improved or is worsening 5 minutes after that first dose, call 911. You may take up to two more tablets at 5-minute intervals while waiting for help (American Heart Association).
Why can't nitrates be combined with erectile dysfunction drugs? PDE-5 inhibitors such as sildenafil, tadalafil, and vardenafil amplify the vasodilation nitrates cause, which can drop blood pressure to dangerous, sometimes fatal levels. Nitrates are withheld for 24 to 48 hours after these drugs (StatPearls).
Why should beta-blockers and long-term nitrates never be stopped abruptly? Sudden withdrawal can trigger rebound hypertension, severe angina, or myocardial infarction. Long-term therapy is tapered over several weeks rather than stopped all at once.
Why are beta-blockers avoided in variant (Prinzmetal's) angina? Variant angina comes from coronary vasospasm. Blocking beta-receptors can leave alpha-mediated vasoconstriction unopposed and worsen the spasm, so nitrates and calcium-channel blockers are preferred for that type.
Why does nitroglycerin often cause a headache? Nitrates dilate blood vessels throughout the body, including those in the head, which produces a throbbing headache, flushing, and sometimes dizziness. A headache can also signal the tablet is still potent.