Caffeine
4 sources
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| PsychonautWiki | TripSit | Pharmacology | DrugCentral | ||
|---|---|---|---|---|---|
| Classification | |||||
| Class / category | — | — | ≈ | ||
| Also known as | Caffeine | coffee | — | — | ≠ |
| Safety | |||||
| Addiction potential | develop with regular consumption, leading to cravings and withdrawal effects upon sudden cessation, but has low abuse potential | — | — | — | |
| Toxicity | The LD50 of caffeine in humans is dependent on individual sensitivity, but is estimated to be about 150 to 200 milligrams per kilogram of body mass or roughly 80 to 100 cups of coffee for an average adult | — | — | — | |
| Dose · Insufflated | |||||
| Threshold | 2.5 mg | — | — | — | |
| Light | 10–25 mg | — | — | — | |
| Common | 25–40 mg | — | — | — | |
| Strong | 40–80 mg | — | — | — | |
| Heavy | 80 mg+ | — | — | — | |
| Dose · Oral | |||||
| Threshold | 10 mg | 10 mg | — | — | = |
| Light | 20–50 mg | 20–75 mg | — | — | ≠ |
| Common | 50–150 mg | — | — | — | |
| Strong | 150–500 mg | 250–400 mg | — | — | ≠ |
| Heavy | 500 mg+ | 400 mg+ | — | — | ≠ |
| Dose · Smoked | |||||
| Threshold | 25 mg | — | — | — | |
| Light | 25–75 mg | — | — | — | |
| Common | 75–125 mg | — | — | — | |
| Strong | 125–175 mg | — | — | — | |
| Heavy | 175 mg+ | — | — | — | |
| Duration | |||||
| Onset | 0.5–2 minutes | 5–10 minutes | — | — | ≠ |
| Total | 1–2.5 hours | 1.5–5 hours | — | — | ≠ |
| After-effects | 6–24 hours | 3–4 hours | — | — | ≠ |
| Pharmacology | |||||
| Receptor activity | — | — | Adenosine receptor A2aAdenosine receptor A2bAdenosine receptor A1Guanine deaminaseAdenosine receptor A3Adenosine receptorAdenosine A2 receptorUncheckedGABA-A receptor; anion channelAmine oxidase [flavin-containing] B | ADORA1ADORA2AADORA2BADORA3ACHEPYGMGDAPIK3CDKCNH2 | ≠ |
| Half-life | — | — | In an average-sized adult or child above the age of 9, the half-life of caffeine is approximately 5 hours. Various characteristics and conditions can alter caffeine half-life. It can be reduced by up to 50% in smokers. Pregnant women show an increased half-life of 15 hours or higher, especially in the third trimester. The half-life in newborns is prolonged to about 8 hours at full-term and 100 hours in premature infants, likely due to reduced ability to metabolize it. Liver disease or drugs that inhibit CYP1A2 can increase caffeine half-life. Elimination 1/2 life in adults = 2.5-4.5 hours; [Reference #1] Caffeine has a plasma half-life (t1/2) of 3 to 5 hours in adults. In one study, when administered to pregnant women prior to delivery, caffeine had a prolonged mean half-life of 80 hours in neonates after delivery. Mean half-life /T 1/2/ and fraction excreted unchanged in urine of caffeine in infants have been shown to be inversely related to gestational/postconceptual age. In neonates, the /T 1/2/ is approximately 3-4 days... The half-time for caffeine is 0.7-1.0 hr in rats and mice, 1-1.6 hr in rabbits, 3-5 hr in monkeys, 4-4.3 hr in dogs and 11-12 hr in baboons. /The authors/ studied 17 preterm infants receiving caffeine, and measured their plasma levels of caffeine and the theophylline metabolite by high-pressure liquid chromatography. The half-life was calculated by computer analysis using the least-square method. The mean gestational age of our patients was 29.7 +/- 1.9 weeks (mean +/- SD) and they were studied at 20.7 +/- 6.6 days (mean +/- SD) postnatal age. The caffeine half-life was 52.03 +/- 23.87 hr (means +/- SD) and the theophylline half-life was 77.04 +/- 65.01 hr (mean +/- SD). | — | |
| Protein binding | — | — | Plasma protein binding of caffeine has not been determined for neonates or infants. In vitro studies indicate a protein binding of about 10%-36%. Caffeine is reversibly bound to plasma proteins. | — | |
Dose at a glance
Each database's primary-route ladder on one shared scale — see where ranges line up or shift.
PsychonautWiki insufflated
TripSit Oral
0500 mg
LightCommonStrongHeavy
Duration at a glance
Total duration on one shared scale.
PsychonautWiki
TripSit
PsychonautWiki summary
For the coffee plant, see Coffea (botany). Summary sheet: Caffeine
TripSit summary
Caffeine is a a CNS stimulant, and also the most widely used psychoactive substance in the world. It is legal and unregulated in most parts of the world, and is found in many commonly sold products. It has a good safety profile, though regular heavy use can cause physical dependence and contribute to certain medical conditions.
Fact-sheets from PsychonautWiki. Harm-reduction reference only — not medical advice.