Reviewing stable, unstable and variant angina;
and drug treatment options
Angina | An Overview
Angina refers to chest pain; a symptom rather than a disease. There are many different types of angina. Here, we review the primary types of angina that you, as a healthcare professional, are expected to know.
Angina is caused by reduced blood flow to the heart – most often due to narrowed or blocked coronary arteries. Symptoms of angina include pressure, squeezing sensation, heaviness, tightness or pain in the chest area. Symptoms may not be limited to the chest either. Shoulders, neck, jaw and back may also be affected. Other symptoms include shortness of breath, nausea, fatigue, sweating and dizziness.
Risk factors for angina include:
- Sedentary lifestyle
- Old age
- Family history of angina
- Diabetes type 2
- High cholesterol levels
- Metabolic syndrome
With these risk factors in mind, let’s review the four different types of angina:
- Stable angina
- Unstable angina
- Prinzmetal’s angina
- Microvascular angina
As part of your pharmacy license exam, you should expect NAPLEX questions on the differences between these angina types, as well as the optimum drug treatment strategy to adopt for each case.
Let’s get started.
Stable and Unstable Angina
Angina may be classified as either stable or unstable.
Stable angina (sometimes called ‘effort angina’) is the most common form of angina. It happens on exertion and goes away after enough rest. Examples include engaging in exercise, climbing stairs; a predictable form of chest pain that is linked to physically exertive activities. Stable angina does not last long, typically only a few minutes and is usually relieved by medicine, such as sublingual nitroglycerin.
In contrast, unstable angina is a medical emergency.
Unstable angina(UA) differentiates itself because it can occur during rest, even after no exertion. Unlike stable angina, then, unstable angina is unpredictable and lasts longer than just a few minutes; it may last for half an hour, or perhaps longer. Even after the use of anti-anginal medicines, unstable angina may not disappear. In more severe cases, unstable angina may itself be a symptom of a myocardial infarction.
Prinzmetal’s angina is also known as variant angina.
This form of angina is different in that it’s triggered by a coronary artery spasm; a situation in which an artery may temporarily narrow. Therefore, less blood can travel to the heart.
In contrast to stable/unstable angina, it is not linked to atherosclerosis and often occurs in younger patients. However, smoking is a common denominator for both forms of angina. Variant angina usually does not progress to myocardial infarction.
Symptoms of variant angina include:
- Repeat episodes of chest pain
- Reduced tolerance to heat
Microvascular angina is also known by the name cardiac syndrome X (CDX).
Like Prinzmetal’s angina, microvascular angina involves artery spasms. This time, though, it affects the smallest arterial blood vessels. Unlike stable angina, symptoms may last for longer than a few minutes, perhaps up to 10-30 minutes or longer.
The pain may be more severe than other forms of angina and may be accompanied by symptoms such as fatigue, lack of energy and shortness of breath. Patients typically present with a normal angiogram.
Alongside lifestyle and perhaps surgical treatment options, such as angioplasty / stenting or coronary artery bypass surgery, here are some of the drug treatment options for patients with angina. As angina is often a symptom of a wider disease, treatment depends on a patient-by-patient basis; which may include one or more of the following drug classes.
- Nitrates–nitroglycerin is a potent vasodilator that reduces myocardial oxygen demand. Nitroglycerin should be avoided in patients taking PDE5 inhibitors, such as sildenafil and tadalafil, as the combination can produce a pronounced hypotensive effect.
- Beta blockers – beta blockers may be used to decrease the heart’s workload, reducing oxygen demand.
- Calcium channel blockers –drugs that include nifedipine and amlodipine which also work to decrease the heart’s workload.
- Statins –drugs used to lower blood cholesterol levels. These drugs are used to reduce long-term risk of serious cardiovascular events.
- Antihypertensive drugs – classes such as ACE inhibitors and angiotensin-receptor blockers (ARBs) may be used to lower blood pressure if patients have hypertension, diabetes or signs of heart failure / chronic kidney disease.
- Antiplatelet drugs – drugs such as clopidogrel may be used to reduce clot formation, particularly in patients who have undergone a coronary angioplasty or who have recently suffered from a myocardial infarction.
- Aspirin – low-dose aspirin decreases the risk of myocardial infarction in patients with chronic stable angina.
Acute attacks of Prinzmetal’s angina respond well to sublingual nitroglycerin. Calcium channel blockers – whether dihydropyridine or non-dihydropyridine – may be used alongside a long-acting nitrate, such as isosorbide dinitrate, for maintenance treatment.
Beta-blockers should be avoided in Prinzmetal’s angina because they may worsen attacks by blocking beta-2 receptor vasodilation.
As part of your pharmacy license exam, you will be asked many NAPLEX questions about the clinical pharmacy of angina; the different types of angina and preferred drug treatment options.
You should prepare for this topic by practicing as many pharmacology quiz questions as possible. The more practice you put in, the better. As part of our online course, we’ve put together a comprehensive range of questions on cardiology and drug treatment options to help prepare you for the pharmacy exam.
Register to NAPLEX Study Guide today to receive instant access to NAPLEX questions on angina and other key aspects of cardiology. To pass your pharmacy license exam, you need to prepare for all aspects of cardiovascular pharmacology.