Antianginal drugs are used primarily to restore the balance between the oxygen supply and demand of the heart. These drugs dilate the coronary vessels to increase the flow of oxygen to the ischemic regions. Other than that, they also decrease the workload of the heart so the organ would have less demand for oxygen. 

Learn about antianginal drugs, nitrates, beta-blockers, and calcium channel blockers in this simplified guide for nursing pharmacology.

Table of Common Drugs and Generic Names

Classification Generic Name Brand Name
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 Blocadren
Calcium-channel blockers amlodipine Norvasc
diltiazem Diltiazem, Diltiazem SR
nicardipine Cardene
nifedipine Adalat, Procardia
verapamil Calan, Isoptin
Others:
Piperazineacetamides ranolazine Ranexa
Nonnitrate coronary vasodilators dipyridamole Persantine

Disease spotlight: Coronary Artery Disease


Coronary Artery Disease (CAD) is the narrowing of blood vessels supplying oxygen and nutrients to the heart, primarily due to the development of fatty tumors (atheromas) in the lumen of blood vessels in a process called atherosclerosis.

  • This pathologic process attracts platelets and clotting factors to the area, causing a much larger obstruction to the vessels. The vessels also lose their natural ability to be elastic, resulting to inability to dilate and constrict. The heart stimulates the blood vessels to deliver more blood but blood delivery is limited by narrow vessel diameter, resulting to low oxygen supply of the heart.
  • As a consequence of hypoxia, pain (angina) is felt.
  • There are two types of angina:
  • classic angina (of exercise), which occurs due to diminished coronary blood flow to the heart; and
  • vasospastic/Prinzmetal’s/variant angina, which is caused by reversible vasospasm even at rest. Both types decrease oxygen supply of the heart.

Nitrates


Description

  • Nitrates are antianginal agents that provide fast action to directly relax smooth muscles and depress muscle tone without affecting nerve activity.
  • Nitrates reduce preload and myocardial muscle tension by dilating the veins. Also, they reduce afterload by dilating the arteries. Both of these actions lower oxygen demand by decreasing the workload of the heart.

Therapeutic Action

  • The main effect is drop in systemic blood pressure.
  • It compensates by increasing blood flow to healthy arteries and veins because affected vessels already lose their elasticity.

Indications

  • Children: May be used only for congenital heart defects and cardiac surgery because they can cause potentially dangerous changes in blood pressure.
  • Adults: Should be educated on drug’s various forms and their proper administration, storage, effectiveness, and manifestations that would warrant prompt medical help. Lifestyle modifications such as smoking cessation, low-fat diet, and weight loss should be encouraged to promote effectiveness of Antianginal therapy.
  • Older adults: Safety measures should be instituted as they are prone to adverse effects like arrhythmias and hypotension. They should receive initial low dose because of probably hepatic and renal impairments which can interfere with metabolism and excretion of drugs.
  • Use during pregnancy is not established.
  • Sublingual nitroglycerin is most effective for recurrent variant angina.
  • Continuous infusion or transdermal patch 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
T1/2: 1-4 min
Metabolism: liver
Excretion: kidney (urine)

Contraindications and Cautions

  • Allergy to nitrates – prevent hypersensitivity reactions
  • Severe anemia – decreased cardiac output (CO) caused by nitrates is dangerous for blood with low-oxygen binding capacity
  • Head trauma and cerebral hemorrhage – relaxation of cerebral vessels can lead to intracranial bleeding
  • Pregnancy and lactation – potential harm to fetus
  • Hepatic and renal disease – alteration in drug metabolism and excretion
  • Conditions that can limit CO (e.g. hypovolemia, hypotension, etc.

Adverse Effects

  • CNS: throbbing headache, dizziness, weakness
  • GI: nausea, vomiting, incontinence
  • CV: hypotension, reflex tachycardia, syncope
  • EENT: pallor, flushing, sweating
  • Large dose leads to methemoglobinemia and cyanosis.

Interactions

  • Ergot derivatives: risk for hypertension; decreased antianginal effect
  • Heparin: decreased therapeutic effect of nitrates
  • PDE-5 inhibitors: risk for severe hypotension

Nursing Management

Nursing Assessment

  • Presence of mentioned contraindications and cautions
  • Skin color and integrity, especially for transdermal or topical forms of nitrates
  • Pain and activity level
  • Neurological status (level of consciousness, affect, reflexes, etc.)
  • Cardiopulmonary status (BP; take heart rate in full minute)
  • Electrocardiogram as ordered
  • Laboratory tests (e.g. CBC, liver and kidney function tests, etc.)

Nursing Diagnoses

  • Decreased cardiac output related to vasodilation and hypotensive effects of the drug
  • Risk for Injury related to adverse effects on neurological and cardiovascular status
  • Ineffective Tissue Perfusion related to low oxygen supply to myocardial cells

Implementation with Rationale

  • Instruct patient not to swallow sublingual preparations to ensure therapeutic effects. Take three tablets with a 5-minute interval, for a total of three doses. If the pain does not subside, seek medical help.
  • Ask for presence of burning sensation to ensure drug potency.
  • Protect drug from sunlight to maintain drug potency.
  • For sustained release forms, take drug with water and do not crush for these preparations need to reach GIT intact.
  • Rotate injection sites and provide skin care as appropriate to prevent skin abrasion and breakdown.
  • Avoid abrupt stop of long-term therapy. Taper doses for 4-6 weeks to prevent myocardial infarction.
  • Provide comfort measures: small frequent meals, appropriate room temperature and lights, noise reduction, ambulation assistance, reorientation, and skin care.

Evaluation

  • Monitor patient response to therapy (pain assessment).
  • Monitor for presence of mentioned adverse effects.
  • Monitor for effectiveness of comfort measures.
  • Monitor for compliance to drug therapy regimen.
  • Monitor laboratory tests.

Beta-Adrenergic Blockers


Description

  • Beta-adrenergic blockers are drugs which block or lyse the effects of sympathetic stimulation. Hence, they are also called as sympatholytics.

Therapeutic action

  • Main effects include decreased blood pressure, contractility and heart rate by blocking the beta-receptors in the heart and juxtaglomerular apparatus of the kidneys. These combined effects reduce the oxygen demand of the heart.
  • Usually used in therapy with nitrates because of reduced adverse effects and increased exercise tolerance.
  • Not indicated for variant angina because therapeutic effect of drugs can cause vasospasm.

Indications

  • Nadolol is used for management of chronic angina. It is the drug of choice in angina patients with hypertension.
  • Propranolol is the prototype drug of this class. It is used for treatment of angina and syncope.
  • Nebivolol, the newest adrenergic blocking agent does not produce the same adverse effects seen in propranolol.

Pharmacokinetics

Route Onset Peak Duration
Oral 15 min 90 min 15-19 h
IV Immediate 60-90 min 15-19 h
T1/2: 3-4 h
Metabolism: liver
Excretion: kidney (urine)
  • Food increases bioavailability of propranolol.
  • Propranolol is the only drug under this class that can cross the blood-brain barrier.

Contraindications and Cautions

  • Bradycardia, heart block, and cardiogenic shock – blocking effect of drugs exacerbates these conditions
  • Pregnancy and lactation – potentially harmful effects to the fetus or neonate
  • Diabetes, chronic obstructive pulmonary disease (COPD), thyrotoxicosis, and peripheral vascular diseases – blocking effect prevents maintaining homeostatic requirements of these diseases

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: increased rebound hypertension
  • NSAIDs: decreased antihypertensive effects
  • Epinephrine: hypertension followed by bradycardia
  • Ergot alkaloids: peripheral ischemia
  • Insulin and oral hypoglycemic agents: alteration in blood glucose levels without the patient experiencing manifestations of hypo- or hyperglycemia

Nursing Considerations

Nursing Assessment

  • Assess for presence of mentioned contraindications and cautions.
  • Assess neurological status to determine presence of neurological adverse effects. Focus on level of orientation and sensory function.
  • Monitor blood pressure and heart rate accurately. Be sure to count the heart rate in one full minute.
  • Auscultate lungs to determine presence of possible respiratory adverse effects.
  • Check color and sensation of extremities. Measure capillary refill. This is to evaluate presence of insufficiencies in the peripheral vascular system.
  • Monitor laboratory test results (e.g. electrolyte levels and renal function tests) to ascertain risk for arrhythmia and discern whether dose adjustment is needed.

Nursing Diagnosis

  • Decreased Cardiac Output related to decreased heart rate, blood pressure, and contractile properties of the heart
  • Ineffective Tissue Perfusion related to decreased blood flow to the heart
  • Risk for Injury related to possible alterations in CNS while on drug therapy

Implementation with Rationale

  • Give drug as ordered following safe and appropriate administration to ensure therapeutic effects.
  • Provide comfort measures: ambulation assistance, raised siderails, appropriate room light and temperature, and rest periods
  • Monitor cardiopulmonary status closely to detect possible alterations in vital signs which signal need for dose adjustment and to prevent related adverse effects.
  • Educate client about the need to not abruptly stop therapy as this can lead to rebound hypertension and myocardial infarction.

Evaluation

  • Monitor patient response to therapy.
  • Monitor for presence of mentioned adverse effects.
  • Monitor for effectiveness of comfort measures.
  • Monitor for compliance to drug therapy regimen.
  • Monitor laboratory tests.

Calcium-Channel Blockers


Description

  • Calcium-channel blockers are drugs which block heart contraction by inhibiting movement of calcium ions, thereby altering arterial and cardiac muscle action potentials.
  • They basically produce vasodilation and relief of spasm.
  • They do not increase lipid levels.
  • Serve as a substitute for classic and variant angina when beta-blockers and nitrates are contraindicated.

Therapeutic Action

  • By blocking contractions, loss of muscle tone and vasodilation occur, consequently decreasing peripheral resistance.
  • Relieves vasospasm in variant angina, thereby increasing blood flow to the heart.
  • Can block atherosclerotic process in endothelial cells
  • Indications
  • Treatment of 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
T1/2: SR (3.5-6h); ER (6-7h)
Metabolism: liver
Excretion: kidney (urine)

Contraindications and Cautions

  • Allergy to drugs
  • Heart block and sick sinus syndrome – conduction problems in these disease may be exacerbated by slow conduction effect of drugs
  • Renal and hepatic dysfunctions – alteration with metabolism and excretion of drugs
  • Heart failure – worsened by decreased cardiac output effect of the drug

Adverse Effects

  • CNS: dizziness, lightheadedness, fatigue, and headache
  • GI: nausea, hepatotoxicity effect of the drug
  • CV: hypotension, bradycardia, peripheral edema
  • EENT: flushing, rash

Interactions

Nursing Considerations

Nursing Assessment

  • Assess for presence of mentioned contraindications and cautions.
  • Inspect skin color and integrity to determine presence of adverse effects on skin.
  • Assess the patient’s complaint of pain and the activity level prior to and after the onset of pain to aid in identifying possible contributing factors to the pain and its progression.
  • Monitor cardiopulmonary status closely as the drug can cause severe effects on these two body systems.

Nursing Diagnosis

Implementation with Rationale

  • Monitor blood pressure and heart rate and rhythm to detect possible development of adverse effects.
  • Provide comfort measures for the patient to tolerate side effects (e.g. small frequent meals for nausea, limiting noise and controlling room light and temperature to prevent aggravation of stress which can increase demand to the heart, etc.)
  • Educate client on measures to avoid angina attacks (e.g. diet changes, rest periods, etc.)
  • Emphasize to the client the importance of strict adherence to drug therapy to ensure maximum therapeutic effects.

Evaluation

  • Monitor patient response to therapy.
  • Monitor for presence of mentioned adverse effects.
  • Monitor for effectiveness of comfort measures.
  • Monitor for compliance to drug therapy regimen.
  • Monitor laboratory tests.

Practice Quiz: Antianginal Drugs


Quiz time! Take our 5-item quiz about antianginal agents!

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Questions


1. Type of angina which involves spasm of the blood vessels

A. Stable angina
B. Pre-infarction angina
C. Unstable angina
D. Prinzmetal angina

2. Contraction and relaxation in each cardiac cycle is controlled by:

A. autonomic nervous system
B. the heart
C. cranial nerves
D. central nervous system

3. All of the following can cause arrhythmia, except:

A. acidosis
B. respiratory depression
C. hyperkalemia
D. none of the above

4. Verapamil and diltiazem belong to which class of antiarrhythmics?

A. Class IV
B. Class III
C. Class Ia
D. Class II

5. The conduction system of the heart include the following:

A. Sinoatrial node
B. Bundle of Purkinje
C. His Fibers
D. Atriomyocardial node

Answers and Rationale


1. Answer: D. Prinzmetal angina.

It is an unusual type of angina which involves the spasm of blood vessels and not just by narrowing of vessels. Person with prinzmetal angina has angina at rest and associated ECG changes.

2. Answer: B. the heart.

Contraction and relaxation is controlled by impulses arising spontaneously in the SA node and transmitted via a specialized conducting system to activate all parts of the muscle almost simultaneously. These rhythmic and continuous contractions are controlled by the heart itself.

3. Answer: D. none of the above.

Electrolyte disturbances, hypoxic conditions, acidosis or accumulation of waste products, and structural damage of the conduction system can lead to arrhythmia.

4. Answer: A. Class IV.

Verapamil and diltiazem are calcium-channel blockers and belong to Class IV antiarrhythmics.

5. Answer: A. Sinoatrial node.

Path of conduction is as follows: SA node -> AV node -> Bundle of His -> Purkinje fibers.

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