Caffeine, which we take from many foods in our daily lives,even in small amounts, can affect our medications when it reaches certain doses. So, what is caffeine? How does it affect the body? How can it change the effects of drugs? For answers, keep reading.

What is caffeine?

Caffeine is one of the most widely used pharmacies in the world. Caffeine includes a variety of analgesics, dietary/nutritional supplements, and cold/flu medications. It is also included in the composition of a number of pharmacological preparations and over-the-counter drugs. It can cause side effects such as irritability, insomnia, diuresis, arrhythmia, headache, tachycardia, respiratory, so it should be taken in limited quantities.

 

The stimulating mechanism of caffeine

The primary mechanism of action of caffeine is the antagonism of adenosine receptors in the brain. Caffeine with this effect temporarily prevents or alleviates drowsiness and thus maintains vigilance, also causes an increase in blood pressure. Caffeine from coffee or other consuming sources is absorbed by the small intestine generally within  45 minutes of digestion and is distributed throughout the body tissues. It is metabolized in the liver into three main substances: paraxanthin (84%), theobromine (12%), and theophylline (4%).

• Coffee and cocoa beans are especially rich in caffeine and theobromines, so when they are consumed in excess, they are associated with certain health problems such as migraines, hypertension, and medications.
• The amount of caffeine in a cup of coffee (150ml) is 60 – 120 mg. 71% of the caffeine in an American diet comes from coffee.
• If the daily use exceeds 500 – 600 mg (4-7 cups of coffee), it may cause serious health problems.

Food	Portion and caffeine amounts (mg)
Chocolate(classic)	50 gr                                  3-63
Wafer	1 bar(46gr)                        5
Dark Chocolate	1 bar(41gr)                        31
Chocolate ice cream	50gr                                    2-5

 

How do caffeine and drugs interact?

 

CYP450 is an enzyme that metabolizes drugs.

They also metabolize environmental toxins, dietary components, and various endogenous substances (e.g., steroids, prostaglandins) that are produced within the body, and the activity of these substances is also a factor in determining the speed at which various drugs are cleared from the body.

Usually, CYP450 enzymes inactivate a drug or compound, but sometimes they make it more active.

Most of the caffeine you ingest is metabolized by a CYP450 liver enzyme called “CYP1A2.”  CYP1A2 enzyme, “demethylate” caffeine molecules; transforming them into other substances. Other drugs metabolized by this enzyme include theophylline, warfarin, and several antidepressants and antipsychotics.

When caffeine is introduced, there is less enzyme available to metabolize these drugs.  What this means is that each acts as a metabolic inhibitor of the other, slowing down the speed with which the body can “break down” or eliminate the drugs.  The result is that the blood level of these drugs, or of caffeine, or of both increases.

For example, a woman who was a heavy coffee drinker who was also taking clozapine (an anti-schizophrenic medication) was found to have about 2 ½ times higher blood levels of the drug when she took caffeine. Because schizophrenic patients commonly consume remarkably high doses of caffeine, such interactions could conceivably constitute a relatively common problem for patients taking that medication.

Caffeine also may cause therapeutic failure in patients receiving lithium (an antipsychotic), may cause toxic reactions in clozapine (another antipsychotic), may augment the efficacy of aspirin and acetaminophen (Tylenol) and may have no significant consequences, despite metabolic interactions, on the effects of mexiletine (an antiarrhythmic).

 

In summary, the medications you are taking, the foods you are eating, even the cigarettes you are smoking, can change the way caffeine is metabolized by your body. And caffeine can also change the way certain other drugs are metabolized.

 

Class of Drug	Generic Name
Antiandrogens	Flutamide
Antidepressants	Amitriptyline Clomipramine Fluvoxamine Mianserin Imipramine
Antipsychotics	Clozapine Haloperidol Olanzapine
Cardiovascular Drugs and Anticoagulants	Lidocaine Mexiletine Propafenone Propranolol Triamterene Verapamil Warfarin
Cholinesterase Inhibitors	Tacrine
Local Anesthetic	Ropivacaine
Nonsteroidal Anti-inflammatory Drugs	Acetaminophen Phenacetin Methotrexate
Quinolones	Pefloxacin

List of drugs whose metabolism is partially or entirely dependent on CYP (1A2), which means that they will be metabolized more slowly when caffeine is used. 

Some Drugs and Interactions

1.Coffee

DRUG	Effect After Interactİon With Coffee
Anagrelide	Edema,stroke,hypotension,arrhythmia
Asenapine	Blood contraction increases to toxic level
Bendamustine	Anemia, infection
Dipyridamole	Recure more doses to work
Hydroxyprogesterone	Decreases the effect of caffeine
Lithium	Can cause lithium toxication
Paracetamol	Increases the reabsorption of the drug
Rasagiline	Cause serious side effects

2.Chocolate

DRUG	Effect After Interaction With Chocolate
Acetaminophen	Increase in absorption of drug
Theophylline	Increase the toxication of drug
Antiaritmics	Arrhythmia risk
Ephedrine	Irritability and anxiety increases
Methylphenidate	Effects increase
Zolpidem	Effects decreases

3.Tea

DRUG	Effect After Interactİon With Tea
Theophylline	Theophylline toxication
Iron-containing preperations	Reabsorption of iron decreases

 

 

REFERENCES
Juan A. Carrillo and Julio Benitez. (2000).  “Clinically Significant Pharmacokinetic Interactions Between Caffeine and Medications,” Clinical Pharmacokinetics, 39(2); 127-153

Jeppesen U, Gram LF, Vistisen K, Loft s, Poulsen HE, Brosen K. (1996) .Dose-dependent inhibition of CYP1A2, CYP2C19 and CYP2D6 by citalopram, fluoxetine, fluvoxamine, and paroxetine. Eur J Clin Pharmacol.  51(1):73-78

Juan A. Carrillo and Julio Benitez. (2000) “Clinically Significant Pharmacokinetic Interactions Between Caffeine and Medications,” Clinical Pharmacokinetics, 39(2); 127-153

Goodman & Gilman. (2009). Tedavinin Farmakolojik Temelleri. Metilksantinler, s. 336, 727-730, 920. Çeviri Editörü: Süzer Ö.Nobel Tıp Kitabevleri Ltd. Şti., İstanbul

Nawrot P, Jordan S, Eastwood J, Rotstein J, Hugenholtzand A, Feeley M. (2003). Effects of caffeine on human health. Food Additives and Contaminants 20(1): 1-30.

Geleijnse JM. (2008). Habitual coffee consumption and blood pressure: an epidemiological perspective. Vascular Health and Risk Management, 4(5):963-70.

.Bonita JS, Mandarano M, Shuta D, Vinson J. (2007). Coffee, and Cardiovascular disease: Invitro, cellular, animal, and human studies. Pharmacological Research, 55(3):187-98.

ÇAKIR ERCİL. (2010, December). Kafein: Kafein Kaynaklaro, Besinlerdeki Kafein Miktarları ve Kafeinin Zararları. Dyt.Sernaz ÇAKIR ERCİL. http://www.tavsiyeediyorum.com/makale_6059.htm

Lowry, N. (n.d.). Tea and theophylline. Helios.Hampshire. Retrieved 2021, from http://helios.hampshire.edu/~nlNS/mompdfs/TeaTheoph.pdf

Çay Bitkisinin Özellikleri » .:: Rize Ziraat Odası ::. (2015, March 17). Rize Ziraat Odasi. http://rizeziraatodasi.com/cay-bitkisinin-ozellikleri/