What are Methylxanthines?

Adrien-Luc Sanders

Methylxanthines are molecular compounds that are derived either naturally or synthetically from xanthine, and are commonly found in medications for certain respiratory problems. They are at once stimulants that can increase heart rate and blood flow and relaxants that can open blood vessels and loosen muscular tissues. Caffeine contains them naturally, and these molecules are one of the main reasons people often feel their hearts racing after consuming a lot of caffeinated foods or drinks. Scientists and pharmaceutical manufacturers often use the molecule in medications designed to combat chronic obstructive pulmonary disease (COPD) and in many cases it can provide almost immediate relief of lung blockages. The compounds can also be found in many types of asthma and bronchial inhalers. In these settings the molecule helps open the airways to make breathing easier.

Methylxanthines can be found in caffeinated drinks like tea.
Methylxanthines can be found in caffeinated drinks like tea.

Molecular Basics

Drugs classified as methylxanthines are actually derivatives of xanthine, which is a purine — a natural and high-protein part of most cells — found in the human body. Xanthines convert through a process known as methylation, which involves adding methyl groups to form alkaloids. This can happen on its own in nature, as is the case with coffee berries and tea leaves, among others. In these cases, the leaves and fruits, which contain caffeine, synthesize xanthines as a part of their natural maturation. All of this happens on the cellular level, usually just as the plants are getting ready to mature. The timing of this process is one of the reasons very young coffees and teas aren’t usually as caffeinated as are blends made from older plants.

Methylxanthines can be derived from chocolate.
Methylxanthines can be derived from chocolate.

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The stimulant can also be artificially created in labs, which is what usually happens when pharmacologists want to use it in medication. Rather than taking the steps of isolating caffeine molecules and then further identifying and separating the natural methylxanthines, scientists generally opt to create the compounds synthetically from xanthines, which are generally pretty plentiful.

Methylxanthines can be found in coffee.
Methylxanthines can be found in coffee.

Treating Lung Conditions

One of the most common pharmaceutical uses for this compound is as an additive to medications for people suffering from COPD. COPD is a lung disease that essentially causes a person’s lungs to lose access to oxygen, often because the heart isn’t able to pump sufficient blood to them. Smoking is one of the leading causes, but certain genetic conditions and other environmental exposures can be to blame, too. Methylxanthines can help by stimulating blood flow and opening blockages. Their effect isn’t usually permanent and they aren’t usually seen as a cure, but they can help immediately and can be a good short-term solution.

Frequent coffee drinkers at times complain of shortness of breath.
Frequent coffee drinkers at times complain of shortness of breath.

These sorts of compounds can also be very helpful for people who have chronic obstructive lung or airway diseases, emphysema, and chronic bronchitis. The molecules act on constricted bronchi and bronchioles to improve airflow, reduce inflammation, and relax airways, all the while increasing blood flow through cardiac stimulation.

Patients with GERD may suffer side effects from methylxanthines.
Patients with GERD may suffer side effects from methylxanthines.

For largely the same reasons, they are commonly found in many asthma medications, too. In these settings they tend to be administered via inhalers or in tablet form. They affect the throat, lungs, heart, and other key parts of the bronchial and pulmonary systems, and the accelerated pulmonary response and relaxation of the airways caused by this medication is why frequent coffee drinkers at times complain of shortness of breath, increased heart rate, and even mild arrhythmia.

As a General Stimulant

Both methylated and nonmethylated synthetic xanthines can be used as mild stimulants more generally, too, which is to say outside of the treatment for any particular condition. Other than caffeine, other compounds in this group include theophylline, aminophylline, paraxanthine, and theobromine. The molecular structures of each of these vary somewhat, but they all have the same core and the same basic characteristics.

Their effect is why people suffering respiratory discomfort, colds, or allergies often self-treat by drinking tea, breathing the steam from tea, or inhaling the aroma of steeping tea leaves, all of which can help to relax airways and ease breathing. While not an effective long-term treatment, these benefits can provide temporary relief from mild discomfort. The compounds are also approved by the International Olympic Committee (IOC), while caffeine in most cases is not. Therefore, Olympic contestants may use these substances to temporarily increase energy and adrenaline response.

Common Risks

Small doses and temporary uses of this compound don’t usually present any serious risks. The molecule is a diuretic, though, which means that it can be dehydrating, and people who are taking it or consuming it should usually be sure to drink plenty of water. Excessive use over long periods of time can cause stress on the heart.

Patients with gastroesophageal reflux disease, or GERD, may also suffer negative side effects from methylxanthines and foods containing them, particularly high-caffeine drinks like coffee and tea or high theobromine foods like chocolate. As the compounds relax the esophagus, they can contribute to gastric reflux reactions. While small quantities may not cause a reaction, larger intakes can lead to nausea and heartburn.

Some medications that are used to treat chronic obstructive pulmonary disease (COPD) contain methylxanthines.
Some medications that are used to treat chronic obstructive pulmonary disease (COPD) contain methylxanthines.

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Discussion Comments


Is this safe? Like in sports supplements?


@Azuza - Methylxanthines in tea is news to me also. I'm glad I now have a fun fact to share when cold and flu season hits.

I did know there were certain foods to avoid if you have GERD, however. I have a good friend that has it and she doesn't eat chocolate or drink coffee. When she was first diagnosed she fought all the restrictions pretty hard, and ended up miserable all the time! So now she just avoids these things and she's much happier.


I had no idea the same compound that is in my asthma inhaler is also in coffee and tea! It kind of makes sense though-racing heartbeat is one of the side effects of asthma medicine and coffee can certainly get your heart rate up!

I'm also a big fan of tea when I'm sick. I always thought it made you feel a little bit better just because it's hot and soothing. I never knew there was actually a compound in it that was helpful.

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