Is Glyceryl Trinitrate (GTN) Spray Good for Shortness Of Breath?

Glyceryl Trinitrate (GTN) spray can be good for shortness of breath (SOB), but only when the SOB is caused by certain conditions such as angina (chest pain), where a narrowing of the coronary arteries (blood vessels) to the heart produces a reduction of oxygen, leading to both pain and shortness of breath. GTN spray will not work for other causes of shortness of breath, such as that caused by respiratory distress, which happens in respiratory illnesses or infections such as asthma, pneumonia and COVID-19. This is because the shortness of breath in these conditions is usually caused by problems in the lungs and not in the heart.¹

What is Glyceryl Trinitrate Spray?

Glyceryl trinitrate (GTN) spray is a medicine that is used specifically for shortness of breath (SOB) and pain caused by an angina attack.¹ An angina attack is defined as pain or discomfort in the chest, often accompanied by shortness of breath. An angina attack is different from a heart attack in that the heart is not left with permanent damage.²  Glyceryl trinitrate spray is also called Nitroglycerin spray in many countries of the world.² To work best, GTN spray has to be sprayed under the tongue which is called sublingual. A popular brand of GTN spray globally is Nitrolingual spray, but there are many other brands too, such as.³ Glyceryl trinitrate (nitroglycerin) belongs to a particular group of medicines called nitrates. These medicines have been used since the 19th century to treat the symptoms of angina. You may have heard that GTN is also used in making dynamite and explosives, which can be a big worry to some people.  This is true, but you can be reassured that making explosives is a very different process from making your spray.⁴ GTN patches and tablets are sometimes used, but Glyceryl trinitrate spray has the advantage of working quickly and being easy to carry and use which is ideal to treat the symptoms of an angina attack.⁵

What is GTN used for?

Glyceryl trinitrate (GTN) is mainly used to treat the symptoms of angina attacks such as pain and shortness of breath. Some of the other nitrates are long-acting and are usually taken as pills or used as patches. The long-acting nitrates are usually used to prevent angina attacks and are taken daily. Your doctor may prescribe both a long-acting nitrate and a GTN spray. Nitroglycerin or GTN tablets and spray are very quick-acting, especially when used sublingually, which means under the tongue. They can be used to relieve an angina attack, or even before an activity that might cause an angina attack, such as exercise or stress.⁶ They have to be used in a specific way to be effective. Your pharmacist or other health care professional can show you the correct way to do this. The tablets work as well as the spray, but tablets deteriorate quickly after they are opened, and are less effective after 8 weeks. Because of this, tablets are less commonly used.⁵

Can GTN be used for shortness of breath?

GTN can be used for shortness of breath but ONLY when the shortness of breath (SOB) is a symptom of angina. Other causes of SOB include:⁷

• Asthma and COPD
• Coronary Heart Disease (CHD), can lead to heart failure, heart attacks and angina
• Cardiovascular Disease which includes CHD and strokes
• Obesity
• Some anaemias 
• Coronavirus (Covid-19)
• Lung infections such as pneumonia 
• Anxiety

The cause of the majority of shortness of breath is a lack of oxygen to the heart or lungs.  Because of the way that GTN spray works it will not be effective for all causes of shortness of breath. It will only be effective when the shortness of breath is associated with the narrowing of the coronary arteries and blood vessels to the heart. With conditions such as anxiety, the shortness of breath is usually due to hyperventilating. With asthma or COPD, the lack of oxygen is due to a problem with the lungs.

Angina (Chest Pain)

Angina (chest pain) occurs when the flow of blood to the heart is reduced, which in turn reduces the amount of oxygen available to the heart, causing symptoms such as chest pain and shortness of breath. People usually describe angina pain as a squeezing, tightening or pressure in the chest or even in the jaw or arms. This can feel like a dull ache or can be extremely painful.⁶ Women can sometimes have different symptoms than men, including pain in the neck and stomach.²  

Other Symptoms of angina are:²

• Dizziness
• Feeling sick (nausea) or being sick
• Sweating 

Cardiovascular Diseases (CVD) are a group of serious heart and blood disorders which includes strokes, heart failure and heart attacks, and often leads to premature death, or death under seventy years old.  CVDs are the cause of most deaths in the world. You will sometimes hear heart attacks called a myocardial infarction or an MI for short. The underlying causes of Cardiovascular diseases include smoking, excess alcohol, lack of exercise and an unhealthy diet, which can lead to being overweight or obese, high blood pressure, raised blood sugars and diabetes and raised blood fats or cholesterol. Angina is not a CVD but it is a common cause of lack of oxygen to the heart, which is a symptom of a problem with the heart.⁸

Angina is most commonly caused by the coronary arteries (blood vessels) to the heart becoming narrowed by a fatty build-up, which is called atherosclerosis. This leads to reduced blood flow and oxygen to the heart and means that there is more chance of having a heart attack or stroke. You will also see this narrowing or blockages of the coronary arteries referred to as Coronary Artery Disease. The risk of angina is increased by the underlying causes of Cardiovascular Disease such as smoking, poor diet and lack of exercise. Family history of heart problems, high blood pressure and aging also increase this risk. Angina can be thought of as a pre-warning for a stroke or heart attack.⁹ 

There are two main types of angina. Stable Angina (sometimes called angina pectoris) is much more common, and attacks will always have a trigger like stress or exercise. The attack will usually stop quickly as soon as you rest. With unstable angina, there is often no trigger and the attack can continue even after resting. This makes unstable angina more problematic. A patient can change from stable angina to unstable angina over time. Chronic angina is also referred to as refractory angina.⁹    

Because angina is a warning sign of serious heart problems such as strokes and heart attacks, treatment will usually include lifestyle advice alongside medicines and occasionally even surgery.  Besides the GTN spray which is used to help with symptoms of angina attacks, it is common for a patient to be given medicines such as a low-dose aspirin to prevent blood clots, a statin to lower blood fat (cholesterol), an ACE inhibitor to reduce blood pressure, or a beta blocker to slow the heart. Although this can seem like a lot of tablets to take, these medicines used together will all help to prevent serious heart problems or strokes.⁹ Exercise can also be  beneficial, and a GTN spray can be really useful here with the pain and shortness of breath, allowing someone to exercise more or maybe for the first time. By following the advice for angina such as medicine and lifestyle changes severe cardiovascular disease can often be prevented.¹⁰

Both the British Heart Foundation (BHF) British Heart Foundation and the American Heart Foundation (AHA) American Heart Association have excellent information on angina, treatments and helpful lifestyle changes to prevent cardiovascular disease, and consequently heart attacks and strokes. The BHF has the following lifestyle advice:

• Stop smoking if you smoke.
• Physical activity:  This can help by controlling your blood sugar and cholesterol levels. Maintaining a healthy weight will also help to control a healthy blood pressure
• Reduce stress: There are various ways of doing this, such as exercise, meditation or yoga.   
• Eat a healthy diet:  Advice includes choosing healthier fats, eating at least 5 portions of fruit and vegetables a day and reducing sugar and salt in your diet.

How Does GTN Work?

Angina chest pain is caused by the narrowing of the blood vessels (coronary arteries) to the heart, which in turn leads to a lack of oxygen causing the heart to work harder and increasing the risk of a heart attack or stroke. The symptoms of angina include chest pain and shortness of breath, particularly upon stress or exercise. 

Glyceryl trinitrate (GTN) works by helping these narrowed blood vessels to relax or open up which leads to a greater flow of blood, and consequently oxygen to the heart. The medical name for this effect is vasodilation. 

Once the heart is receiving more oxygen the pain of angina, and the other symptoms such as shortness of breath, are greatly reduced or even disappear. GTN sprays such as Nitrolingual spray will deliver a set dose of 400mcg which will work very quickly, usually within 2 minutes, and last for half an hour. Sometimes the spray might need to be repeated after 5 minutes.^5,10

Side effects and drug interactions of GTN

GTN will not only relax and open up blood vessels in the heart but also in the rest of your body. Possible side effects include headaches, light-headedness and flushing of the face. These are the most common side effects and are worth discussing with your healthcare professional if you find them troublesome. In some people, it can cause very low blood pressure, blurred vision, confusion and for them to feel sick.⁵

Because medicines for erectile dysfunction such as Viagra (sildenafil) and Cialis (tadalafil) work in a similar way to GTN they should not be taken at the same time. This can lead to a dangerous drop in blood pressure. 

Other medicines can also have the same effect on blood pressure, including some blood pressure medicines. GTN shouldn’t be taken by people with heart problems other than angina, or who have had a certain type of stroke or a recent bleed in the brain. Glyceryl trinitrate, along with the other nitrates, can become less effective with time, or if you are using the medication very frequently.

If you are unsure of the medicines you are taking or any medical problems you may have or feel that your GTN spray is not working as well as it was, it is always best to check with your pharmacist or doctor.⁵

What Happens if you Take GTN Without Needing to?

If you have taken GTN spray without needing to or used too much, the best thing to do is to lie or sit down and raise your feet. If you have taken a GTN spray without needing to you may experience:

• Headache
• Feeling faint
• Dizziness
• Confusion
• Nausea
• Feeling flushed and clammy
• A faster heart rate

Because the effects of GTN are short-lived, these side effects should pass fairly quickly. In most cases, side effects should pass within the hour. Usually, you will not need medical treatment but you should contact your doctor if these side effects do not go away. 

If you lose consciousness, have a seizure, or have lost the ability to move you should contact emergency services straight away. This is also the case If you have taken 3 doses of GTN spray and your chest pain or SOB is still not improving.¹⁰

Summary

Glyceryl trinitrate (GTN) spray can be good for shortness of breath but only when it has been caused by an angina attack. A common brand of spray that you might be given is called Nitrolingual pump spray. For GTN spray to be effective it is important that you use it as the doctor or healthcare professional (HCP) has told you. GTN or nitroglycerin spray will not work for all causes of shortness of breath and you should only use it when you have been advised to do so by an HCP.  

Angina is chest pain and shortness of breath that is caused by the narrowing of the coronary arteries. Angina can be thought of as a pre-warning for a heart attack or stroke and is usually a symptom of underlying heart problems.  Because of this, your doctor will normally advise other medicines, such as a low dose aspirin, blood pressure and cholesterol tablets. Along with lifestyle changes, including improving your diet, giving up smoking and alcohol and exercising These medicines can greatly reduce your risk of developing cardiovascular disease (CVD).  One of the advantages of using GTN spray before exercise is that it will alleviate the pain and shortness of breath that might have prevented you from exercising before. New exercise regimes should always be discussed with your doctor. 

GTN spray works by dilating or relaxing the blood vessels in the heart (coronary arteries). As it also relaxes other blood vessels, it can be a problem with other medicines that have the same effect, such as those used to treat erectile dysfunction, or some blood pressure medicines. Overall, it is usually very effective in treating shortness of breath due to an angina attack and has few side effects.