Products
Caffeine is commercially available as a drug in the form of tablets, effervescent tablets, lozenges, as a pure powder and as a juice, among others. It is present in numerous stimulants; these include coffee, cocoa, black tea, green tea, matcha, iced tea, mate, soft drinks such as Coca-Cola, and energy drinks such as Red Bull. No other psychoactive substance is consumed as frequently worldwide as caffeine.
Structure and properties
Caffeine (C8H10N4O2, Mr = 194.2 g/mol) exists as a white crystalline powder or in the form of silk-like crystals. It sublimes readily and is sparingly soluble in water. However, it dissolves readily in boiling water. Caffeine is a trimethylated xanthine derivative. It is a natural compound and an alkaloid found in coffee, black tea, mate, guarana, cocoa, and cola seeds, among others.
Effects
Caffeine (ATC N06BC01) stimulates the central nervous system, respiration, and cardiovascular system. It keeps you alert, promotes concentration and performance, has diuretic properties, and stimulates digestion. The effects are due to antagonism at adenosine receptors. Caffeine is very well absorbed and rapidly crosses the blood–brain barrier into the CNS. It is almost completely metabolized and excreted predominantly renally. The half-life is approximately 3 to 5 (to 10) hours in adults.
Indications and indications
- Against fatigue, to promote alertness and performance, as a smart drug.
- In combination with painkillers for the treatment of headaches and migraines.
- To relieve fatigue under antihistamines.
- Premature apnea see under caffeine citrate solution.
- In cosmetics, e.g. against hair loss.
Contraindications
Caffeine is contraindicated in case of hypersensitivity. Patients with cardiac arrhythmias should avoid high doses. Caution is advised in cases of gastric or intestinal ulcers. In our opinion, children should not take caffeine. For complete precautions, see the drug label.
Interactions
Caffeine is metabolized primarily by CYP1A2. Appropriate drug-drug interactions with CYP substrates, CYP inhibitors, and CYP inducers are possible. Other interactions may include those with stimulants, stimulants containing caffeine, centrally depressant drugs, and cardiac-active agents (eg, sympathomimetics).
Adverse effects
- Restlessness, irritability, nervousness, sleep disturbances, anxiety.
- Rapid heart rate, hypertension, arrhythmias.
- Increased urination
- Nausea, indigestion, stomach burning, reflux (GERD).
- Discoloration of the teeth
Regular consumption leads to dependence and tolerance. With abrupt discontinuation, withdrawal symptoms such as a caffeine withdrawal headache and irritability may occur. See coffee withdrawal and caffeine withdrawal.
Overdose
Caffeine should not be overdosed because it can cause cardiac arrhythmias and other health problems. Symptoms of overdose include tremors, restlessness, insomnia, nausea, vomiting, rapid pulse, confusion, visual disturbances, delirium, convulsions, hypokalemia, and hyperglycemia.
