Prevalence
Although exact rates of prevalence are not available, general population data shows a 0.002% prevalence over a year-long period and higher prevalence within clinical populations. Caffeine
Caffeine is a methylxanthine, and is hydrophobic. The structure of caffeine allows the molecule to pass freely through biological membranes including the blood-brain barrier. Absorption in the gastrointestinal tract reaches near completion at about 99% after only 45 minutes. Half-life of caffeine for most adults is between 2.5 and 4.5 hours when consumption is limited to less than 10 mg/kg. However, during neonatal development, half-life for the fetus is significantly longer and decreases exponentially after birth to reach a normal rate at about 6 months. Cytochrome P-450, a hemeprotein, acts in liver microsomes to metabolize caffeine into dimethylxanthines, monomethylxanthines, dimethyl uric acids, monomethyl uric acids, trimethylallantoin, dimethylallantoin, and derivatives of uracil. Most caffeine is metabolized by 3-methyl demethylation, forming the metabolite of paraxanthine. Many metabolites, in addition to caffeine, act within the body and are partly responsible for the physiological response to caffeine. Mechanism of caffeine action
Caffeine acts in multiple ways within the brain and the rest of the body. However, due to the concentration of caffeine required, antagonism of adenosine receptors is the primary mode of action. The following mechanisms are ways in which caffeine may act within the body, but depending on necessary caffeine concentration and other factors may not be responsible for the clinical effects of the substance.
Reticulocytosis is a condition where there is an increase in reticulocytes, immature red blood cells. It is commonly seen in anemia. They are seen on blood films when the bone marrow is highly active in an attempt to replace red blood cell loss such as in haemolytic anaemia, haemorrhage. == External links ==