A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers (Pentadactyly). Land vertebrate fingers
The five-rayed anterior limbs of terrestrial vertebrates can be derived phylogenetically from the pectoral fins of fish. Within the taxa of the terrestrial vertebrates, the basic pentadactyl plan, and thus also the fingers and phalanges, undergo many variations.Morphologically the different fingers of terrestrial vertebrates are homolog. The wings of birds and those of bats are not homologous, they are analogue flight organs. However, the phalanges within them are homologous.Chimpanzees have lower limbs that are specialized for manipulation, and (arguably) have fingers on their lower limbs as well. In the case of Primates in general, the digits of the hand are overwhelmingly referred to as "fingers". Primate fingers have both fingernails and fingerprints.Research has been carried out on the embryonic development of domestic chickens showing that an interdigital webbing forms between the tissues that become the toes, which subsequently regresses by apoptosis. If apoptosis fails to occur, the interdigital skin remains intact. Many animals have developed webbed feet or skin between the fingers from this like the Wallaces flying frog. Human fingers
Usually humans have five digits, the bones of which are termed phalanges, on each hand, although some people have more or fewer than five due to congenital disorders such as polydactyly or oligodactyly, or accidental or intentional amputations.
Side effects
Side effects of PPIs in general and lansoprazole in particular may include:
Common: diarrhea, abdominal pain
Infrequent: dry mouth, insomnia, drowsiness, blurred vision, rash, pruritus
Rarely and very rarely: taste disturbance, liver dysfunction, peripheral oedema, hypersensitivity reactions (including bronchospasm, urinary, angioedema, anaphylaxis), photosensitivity, fever, sweating, depression, interstitial nephritis, blood disorders (including leukopenia, leukocytosis, pancytopenia, thrombocytopenia), arthralgia, myalgia, skin reactions including (erythroderma, Stevens–Johnson syndrome, toxic epidermal necrolysis, bullous eruption)PPIs may be associated with a greater risk of hip fractures and Clostridium difficile-associated diarrhea. : 22

Interactions
Lansoprazole interacts with several other drugs, either due to its own nature or as a PPI. PPIs reduce absorption of antifungals (itraconazole and ketoconazole)  and possibly increase digoxin in plasma
Increases plasma concentrations of cilostazol (risk of toxicity)Lansoprazole possibly interacts with, among other drugs:

sucralfate
ampicillin
bisacodyl
clopidogrel
delavirdine
fluvoxamine
iron salts
voriconazole
aminophylline and theophylline
astemizole

Chemistry
It is a racemic 1:1 mixture of the enantiomers dexlansoprazole and levolansoprazole. Dexlansoprazole is an enantiomerically pure active ingredient of a commercial drug as a result of the enantiomeric shift. Lansoprazoles plasma elimination half-life (1.5 h) is not proportional to the duration of the drugs effects to the person (i.e. gastric acid suppression). History
Lansoprazole was originally synthesized at Takeda and was given the development name AG 1749. Takeda patented it in 1984 and the drug launched in 1991. In the United States, it was approved for medical use in 1995. Society and culture
Patents
The lansoprazole molecule is off-patent and so generic drugs are available under many brand names in many countries; there are patents covering some formulations in effect as of 2015. Patent protection expired on 10 November 2009.