Caffeine: Interactions and Uses

As common as caffeine is for most of us, it’s important to remember that it can cause interactions when combined with alcohol or medications. But when should caution be taken when drinking coffee or taking caffeine tablets? And which foods contain caffeine? Read that and more here.

Caffeine: interactions and contraindications.

When consuming caffeine, it can interact with various medications:

  • If medications such as sympathomimetics that increase heart rate are taken, caffeine can further enhance their effects.
  • Calming agents, on the other hand, caffeine counteracts.
  • It should also be noted that caffeine breakdown in the body is accelerated by smoking, but hindered by the active ingredients cimetidine and disulfiram.
  • Furthermore, caffeine increases the effectiveness of painkillers with the active ingredients acetylsalicylic acid or paracetamol. If painkillers are taken together with caffeine, the dose of painkillers can therefore usually be reduced. More detailed information on the interaction of caffeine and painkillers should ask your doctor.

Caffeine and alcohol

Recent studies suggest that there may also be interactions when alcohol and caffeine are taken at the same time. People who only drink alcohol get tired faster and are also more likely to notice that they are drunk. By additionally taking caffeine, however, drunk people no longer perceive their intoxication or only in a weakened form. That’s why mixing alcohol and caffeine makes you feel more powerful for longer.

Caffeine in diseases and pregnancy

People with heart problems should clarify with the attending physician whether and how much caffeine they may consume. The same applies to people suffering from hyperthyroidism, cirrhosis of the liver, or anxiety syndrome. How much caffeine is allowed during pregnancy is controversial: small amounts of caffeine were long considered not harmful. However, recent studies indicate that even small amounts of caffeine could significantly increase the risk of miscarriage. Therefore, it is recommended to avoid caffeine during pregnancy.

Caffeine in coffee, tea and cola

Caffeine is mainly found in beverages. The best known drinks with caffeine are coffee, cola and tea. In tea, the caffeine is called teein, however, the two substances are chemically identical. They differ only in the way they are released: while caffeine is already released on contact with gastric acid, teein does not develop its effect until it reaches the intestine: as a result, the effect occurs later, but also lasts longer. In addition to coffee and tea, caffeine is also contained in cocoa and energy drinks, as well as in chocolate. The higher the cocoa content of chocolate, the higher the caffeine content – at 100 grams of chocolate, this is almost equivalent to a small cup of coffee. Children in particular should be careful with drinks and foods such as cola and chocolate: Three glasses of cola and three chocolate bars already contain about as much caffeine as two cups of coffee. Such caffeine consumption can cause side effects in children, such as nervousness or sleep disturbances.

Caffeine content of foods

The following is a list of various foods and their caffeine content:

  • Cup of coffee (150 milliliters): 80 – 120 milligrams of caffeine.
  • Cup of black tea (150 milliliters): 20 – 40 milligrams of caffeine.
  • Cup of espresso (30 milliliters): 40 milligrams of caffeine
  • Cup of cocoa (150 milliliters): 6 milligrams of caffeine
  • Glass of cola (150 milliliters). 15 – 35 milligrams of caffeine
  • Energy drink (150 milliliters): 48 milligrams of caffeine.
  • Bar of chocolate (100 grams): depending on the type of chocolate between 15 milligrams (milk chocolate) and 90 milligrams (dark chocolate).
  • Caffeine tablets (per piece): Depending on the dosage between 50 and 200 milligrams of caffeine.

Products with caffeine

Meanwhile, caffeine is found not only in food, but also in various other products: These include, for example, hair shampoos with caffeine. They are supposed to prevent hair loss – however, their effectiveness is controversial. In addition to hair shampoos, caffeine is also used in various skin care products, as it is said to have a skin-tightening and skin-smoothing effect.Furthermore, there are also special caffeine tablets, which are said to increase attention and concentration in the short term. With such caffeine tablets, however, one should always consider possible side effects.

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  • Nieber et al. (2007): Caffeine. Luxury food and drug. In: Pharmazeutische Zeitung, Vol. 4. (Retrieved: 04/2020).

  • Beiglböck, Wolfgang (2016): Caffeine. Stimulant or addictive substance. Springer Verlag, 1st edition.