Mateine

Caffeine

Clinical data
Pronunciation	/kæˈfiːn, ˈkæfiːn/
AHFS/Drugs.com	Monograph
Pregnancy category	AU: A US: C (Risk not ruled out)
Dependence liability	Physical: low–moderate Psychological: low
Addiction liability	Low / None
Routes of administration	By mouth, insufflation, enema, rectal, intravenous
Drug class	Stimulant
ATC code	N06BC01 (WHO)
Legal status
Legal status	In general: unscheduled
Pharmacokinetic data
Bioavailability	99%
Protein binding	25–36%
Metabolism	Primary: CYP1A2 Minor: CYP2E1,CYP3A4,CYP2C8,CYP2C9
Metabolites	Paraxanthine (84%) Theobromine (12%) Theophylline (4%)
Onset of action	~1 hour
Biological half-life	Adults: 3–7 hours Neonates: 65–130 hours
Duration of action	3–4 hours
Excretion	Urine (100%)
Identifiers
IUPAC name 1,3,7-Trimethylpurine-2,6-dione
Synonyms	Guaranine Methyltheobromine 1,3,7-Trimethylxanthine Theine
CAS Number	58-08-2 Y
PubChem CID	2519
IUPHAR/BPS	407
DrugBank	DB00201 Y
ChemSpider	2424 Y
UNII	3G6A5W338E
KEGG	D00528 Y
ChEBI	CHEBI:27732 Y
ChEMBL	CHEMBL113 Y
PDB ligand	CFF (PDBe, RCSB PDB)
ECHA InfoCard	100.000.329
Chemical and physical data
Formula	C8H10N4O2
Molar mass	194.19 g/mol
3D model (JSmol)	Interactive image
Density	1.23 g/cm3
Melting point	235 to 238 °C (455 to 460 °F) (anhydrous)
SMILES CN1C=NC2=C1C(=O)N(C(=O)N2C)C
InChI InChI=1S/C8H10N4O2/c1-10-4-9-6-5(10)7(13)12(3)8(14)11(6)2/h4H,1-3H3 Key:RYYVLZVUVIJVGH-UHFFFAOYSA-N Y
See also: data page

Structure of a typical chemical synapse
Postsynaptic density Voltage- gated Ca++ channel Synaptic vesicle Neurotransmitter transporter Receptor Neurotransmitter Axon terminal Synaptic cleft Dendrite

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is the world's most widely consumed psychoactive drug. Unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. There are several known mechanisms of action to explain the effects of caffeine. The most prominent is that it reversibly blocks the action of adenosine on its receptor and consequently prevents the onset of drowsiness induced by adenosine. Caffeine also stimulates certain portions of the autonomic nervous system.

Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine bases of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia and helps to protect them against predator insects and to prevent germination of nearby seeds. The most well known source of caffeine is the coffee bean, a misnomer for the seed of Coffea plants. Beverages containing caffeine are ingested to relieve or prevent drowsiness and to improve performance. To make these drinks, caffeine is extracted by steeping the plant product in water, a process called infusion. Caffeine-containing drinks, such as coffee, tea, and cola, are very popular; in 2005, 90% of North American adults consumed caffeine daily.