Winter, cold wind, long queues at the hospital, feverish forehead, anxious mood...

The cold season has arrived as expected. Waiting in line for five hours and seeing a doctor for five minutes, such a helpless scene is presented again...

When I came out of the hospital, I always had a box of cold medicine in my hand. Ganmaoling capsules, Ganmaoling granules, Gankang, Sanlitong... Common cold symptoms such as fever, headache, runny nose, etc., always need to be treated with medicine.

When I got home and read the instructions carefully, I found that these medicines all contained a substance that was both familiar and unfamiliar: caffeine.

Can caffeine cure a cold?

If the answer is "yes", then why no doctor tells you to drink more coffee or tea when you have a cold?

If the answer is "no", then what about the caffeine in cold medicine?

How to extract caffeine is a necessary skill for every student in pharmacy school

Both tea leaves and coffee beans contain caffeine, and the content is not low.

As an alkaloid, the caffeine content in tea can reach 2% to 5%, which seems considerable.

In China, almost every student in a pharmaceutical school will go through an experimental class: extracting caffeine from tea leaves.

Caffeine sublimates at 235-238 degrees Celsius and "floats out" from the tea leaves. After being processed by a simple sublimation device, it condenses into caffeine crystals on a piece of filter paper, which are crystal clear and very beautiful.

This experiment tells us that, first, caffeine is not difficult to obtain, and it is not a controlled drug, otherwise so many students would be suspected of committing a crime by extracting it in large quantities in the laboratory; second, caffeine is a relatively basic drug, otherwise students would not take the time to do such experiments and familiarize themselves with caffeine extraction techniques and processes.

Obviously, in addition to being the "soul" of the beverage, caffeine is also a medicine.

In addition to refreshing the brain, what other pharmacological effects does caffeine have?

The work of the cerebral cortex requires the support of signal transmission at neuronal synapses. Caffeine can stimulate calcium ion-mediated calcium ion release in postsynaptic neurons, thereby controlling the release of neurotransmitters.

Don’t understand? You can understand it this way: neurons that transmit signals to the cerebral cortex work from 9 to 5, and when they are tired and have no strength, they also need to rest.

When caffeine comes, it will say to the tired and panting neurons: Move! Move! Don't stop! Good tea and good wine, I have them all here, eat and drink for free, just don't give up your work!

If neurons continue to work, the cerebral cortex will continue to be excited, and the person will continue to be awake.

Therefore, drinking caffeinated beverages can refresh the mind, but many people will also suffer from insomnia, and some people will experience anxiety, irritability, and irritability. Of course, the effect varies from person to person.

In addition to the excitatory center, caffeine also promotes the synthesis and release of catecholamines.

Catecholamines are substances with positive inotropic effects (“inotropic” here refers to the myocardium), which can increase heart rate and blood pressure. In addition, they also have effects such as constriction of cerebral blood vessels.

There are huge individual differences. Some people's hearts start pounding after just one sip of coffee, while others can drink several cans of coffee a day without blushing or feeling any heart palpitations.

Caffeine "wanders" into the kidneys and acts as a diuretic. This effect is related to the frequent trips to the toilet after drinking tea.

Caffeine can also affect the digestive tract and increase gastric acid secretion. People with digestive tract ulcers are not suitable for drinking beverages containing caffeine.

Central nervous system excitation, positive inotropic effect, vasoconstriction effect, diuretic effect, gastrointestinal effect...Yes, these are the pharmacological effects of caffeine, but after all this talk, what is the relationship between caffeine and cold medicine?

With caffeine in cold medicine, these effects can be doubled with half the effort

First, caffeine has an analgesic effect.

Caffeine alone has no analgesic effect. It is meaningless to expect to relieve symptoms such as headaches and muscle aches after a cold by drinking tea or coffee.

Therefore, non-steroidal antipyretic analgesics have taken on the task of relieving pain in cold medicines. The most common is acetaminophen, and there are also ibuprofen or aminopyrine.

Magically, when caffeine meets these painkillers, it gets the chance to start playing the role of analgesic adjuvant.

Pain also needs to pass through neurons to transmit signals from the painful area to the brain. Caffeine can "intercept" pain signals, that is, it has the effect of blocking the transmission of pain signals.

Compared with the use of non-steroidal antipyretic analgesics alone, the combined use of caffeine and non-steroidal antipyretic analgesics can achieve 2 to 3 times the analgesic effect.

Secondly, caffeine has the effect of constricting cerebral blood vessels.

Yes, the effect of constricting cerebral blood vessels has been mentioned before. What does this have to do with colds?

Many headaches are caused by increased blood flow to the cerebral blood vessels.

Is this another new understanding? I used to think that migraine and other diseases, when the pain is so severe that you want to bang your head against the wall, are caused by blood vessels in the brain being blocked. On the contrary, it is not that there is too little blood flow, but that there is too much blood flow. Reducing extracranial blood flow can greatly relieve symptoms.

The classic drug for controlling migraine symptoms: Noning tablets, also known as aminocaca tablets, contain caffeine. Although it can only be used in the short term, the role of caffeine in it is clear.

Coca-cola also contains caffeine. It is said that a pharmacist originally mixed Coca-cola to treat migraines...

Finally, caffeine can also counteract the drowsiness side effect of cold medicines to some extent.

A common cold medicine: chlorpheniramine, also known as chlorpheniramine. The medicine is good, but the side effects are a bit difficult to control: it makes people sleepy!

Therefore, almost all cold medicines have warnings, reminding people to avoid driving a motor vehicle, operating machinery, and working at heights after taking the medicine.

Caffeine can alleviate the drowsiness caused by chlorpheniramine to a certain extent. But to be honest, this counteracting effect is limited. Therefore, even if it contains caffeine, you will still feel sleepy. For safety, it is better not to drive after taking cold medicine!

Can taking cold medicine cause caffeine addiction?

Colds are self-limiting diseases, and the usual course of illness is about one week. Therefore, a box of common cold medicine is only enough for about one week.

Taking it for such a short time will not cause addiction.

Although in theory it can increase blood pressure and cause anxiety, existing clinical data show that caffeine has no obvious toxicity and will not increase the incidence of cardiovascular and cerebrovascular diseases or cancer.

At therapeutic doses, caffeine in cold medicines does not pose a health hazard unless there are contraindications.

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