Pharmacy Technicians Course. LaGuardia Community College
Gastrointestinal System (GI tract)Is a long tube that consists
of the mouth, esophagus, stomach, small intestine, large intestine,
rectum and anusSeveral organs empty into the GI tract. These
include the liver, pancreas, and the gall bladder with the salivary
glandsThe main function of the GI tract is digestion and absorption
of nutrientsThe movement of the smooth muscles in the GI is called
peristasis and propels food in the forward direction
Mouth and oral cavityTeeth normally masticate food which
increases the surface area for digestive enzymes to workSalivary
amylase is secreted and begins the digestion of starch and complex
carbohydrates into disaccharides and trisaccharidesThe oral cavity
is also called the pharanyxEsophagus delivers the food to the
stomachStomach The stomach further processes the food into a
semisolid substance called chymeParietal cells of the stomach also
secretes HCL HCL activates pepsinogen into active enzyme called
pepsin.Pepsin begins the breakdown of proteins in the food into
amino acid peptidesParietal cells also secrete intrinsic factor
which is important for absorption of vitamin B12 in the
ileumBicarbonate in the mucus in the stomach is present to protect
the lining of the stomach from the low pH of the acid
environmentSmall IntestineDuodenum is the part of the small
intestine where most of the digestion occursPancreas secretes
alkaline pancreatic juice which contains an amylase which further
breaks down sugars, chymotrypsin (which will break down proteins),
lipases (which will break down fats)Additional the liver produces
bile acids and the gallbladder stores the acids until needed. When
food enters the duodenum CCK is release and the gallbladder pumps
bile acids into the duodenumBile acids solubilize the fats into
micelles to increase the surface area for pancreatic lipase to
work.End products of DigestionCarbohydrates to glucose and/or
FructoseProteins to amino acids and same peptidesFats to fatty
acids and glycerolFats are transported via chylomicrons to the
liver where VLDL, and LDL are secretedThe enterocytes of the small
intestine will absorb these and the mesenteric veins will empty
into hepatic portal vein which carries nutrients to the liver
(first pass) Large IntestineThe main function of the large
intestine is to absorb water and electrolytes into the blood
streamIf too much water is absorb the result is constipationIf too
little is absorbed the result is diarrheaDisorders of the GI
systemGastroesophegeal reflux or GERD caused by abnormal amounts of
acid in stomachor esophageal sphincter functionDefective
prostaglandin synthesis and defective bicarbonate production
(NSAIDs, and ASA)Tx: antacids containing calcium carbonate (TUMS)
or aluminum and magnesium hydroxide (MAALOX)Alternatives are PPI
(proton pump inhibitors)Nexium (esomeprazole)Protonix
(pantaprazole)Aciphex (rabeprazole)Prilosec (Omeprazole)Drugs work
on the parietal acids to block HCL secretionNausea and Vomiting
(NV)Common seen in pregnancy, overeating, alcohol consumption,
illness, bacterial or viral gastroenteritis, food poisoning, and
post operative statesA common side effect to opiate medicationsA
common side to diabetic gastroparesisDrugs that are used to treat
NV5 HT3 agonist : ondansetron (Zofran), granisetron (Kytril) the
gold standard in NV tx in chemotherapyDopamine blockers:
Prochlorperazine (Compazine): classical used in the morning
sickness. Dopamine blockers/GI stimulant: Metoclopramide (Reglan)
used in tx of diabetic gastroparesisMalabsorption diseasesCeliac
disease: autoimmune disease of the small intestine where there is a
senstivity to glutenGluten also known as wheat protein is a trigger
for this reaction.Results in severe diarrhea and profound
electrolyte loss Malabsorption of fat soluble vitamins (bleeding
disorder)Other names for this disease is nontropical sprue, or
Gluten insensivityTropical Sprue: a disease causing the villi of
the small intestine to stop absorbing nutrients. Can be
fatalProfound loss of all nutrients and fat soluble vitaminsBelieve
to be caused by a bacterial factor.Treated with a course of Abx:
DoxycyclinePancreatic disease including pancreatic cancer,
pancreatitis and cystic fibrosisCholestatic jaundice
ConstipationResults from:Inadequate water intakeInadequate fiber
intakeChanges in lifestyleLack of exerciseDrugs like opiatesAbuse
of laxativesTherapy of constipationBulk forming laxative commonly
include fiber which increases bulk of stool to stimulate GI tract.
Includes: Metamucil (psyllium)Emollient makes the fecal matter
slippery includes mineral oil enema (Fleet mineral oil)Surfactants
makes the feces more soft: Colace (docusate sodium)Saline laxative
powerfully draws water into the stool. Includes magnesium citrate
(Citroma), and sodium phosphates (Fleet Phosho Soda)Evacuants work
similar to saline laxatives: Golytely (PEG with lytes)Stimulants:
triggers the nerve that control bowel movements to work. Includes
bisacodyl (Dulcolax) and Senna (sennakot)Therapy of
DiarrheaDiarrhea is a loss of water and electrolytes as a result of
infections or inflammation of the large or small intestine.Bloody
diarrhea is sometimes called dysentery and result in infection with
salmonella (Typhus fever), shigella, or E. Coli Treated with Abx:
fluoroquinolones or BactrimCholera is disease of the third world
where a spirochete, called Vibrio Cholerae infects the small
intestine and its toxin produce profound loss of water and
electrolytes. Potentially fatal if untreated with Abx and IV
hydration
Diarrhea can be treated with fiber Absorbs water from the GI and
swells to provide bulkExamples are Metamucil (natural psyllium
hulk) or fiber from fruits and vegetablesCan be treated with
narcotics and narcotic derivativesOpium Tincture sig: 0.25 ml-0.5
ml bid as needed to limit bowel movements. Caution: tincture as
high concentration. Can result in overdose.Lomotil
(Diphenoxylate/Atropine) CVImodium (Loperamide, a meperidine
derivative)
Liver DiseaseLiver pathology includes hepatitis, cirrhosis, and
cancerDamage to the liver can also occur from drugs. Drugs that can
cause liver damage are: acetaminophen (Tylenol), amiodarone
(Cordarone), anabolic steroids, isoniazid, oral contraceptive
agents, methotrexate, allopurinol (Zyloprim)HepatitisInflammation
of the liverCaused by viruses in most cases. Hepatitis B and C is
life long and can lead to hepatocellular carcinoma and cirrhosis of
the liver. CMV can also cause hepatitisCan be caused by
drugsAlcoholHepatitis A virus (HAV)Transmitted by oral-fecal route
in endemic areaSymptomic therapy; not life longPrevented by
vaccination: Havrix (GSK) and Vaqta (Merck)Hepatitis B (HBV)serum
hepatitisTransmitted by blood or infected bodily fluid contact with
mucus membranes or by blood transfusions or by poorly sterilized
medical devices (needles)Can be transmitted to a fetus by an
infected motherNew born babies are vaccinated at birthRecombivax
0.5 ml IM or Energix 0.5 ml IMhepatitis B surface antigen (HBsAg)
produced in yeast cellsAcute infection causes vomiting, abdominal
pain, jaundice and sometimes hepatic failure and deathChronic
infection leads to cancer and cirrhosisTherapy of HepatitisTherapy
is complex and involved drug, antibody level and viral load
monitoringAntiviral drugs (similar to HIV drugs)Lamivudine
(Epivir)Adefovir (Hepsera)Tenofovir (Viread)Entacavir
(Baraclude)Interferons are drugs that modify the immune response to
the viral infectionInterferon alpha (Intron A, Roferon)Interferon
alpha (peglyated): Pegasys give weeklyThese drugs cool the immune
reaction to viral does not clear the infectionCirrhosisEnd stage
liver diseaseFibrosis of the sinusoids of the liverComplications:
bleeding, CNS edema, renal dysfunction, ascites, hypoglycemia,
hepatic bone disease (osteodystrophy), bleeding into the GI tract
from varicesTerminal conditionChronic hepatitis and carcinoma leads
to cirrhosisExtreme alcohol consumptionLiver Transplant is only
cureAmino AcidsThe body can produce 11 types of amino acids,
referred to as nonessentialThere are 9 types of amino acids that
the body requires, but cannot produceThese are referred to as
essential amino acids (See table 23.9)Essential amino acids have to
be derived from food intake19Vitamin DHelps with the absorption of
calcium from the intestine to make stronger bones and
teethDeficiency causes metabolic bone softening:Called rickets in
childrenCalled osteomalacia in adultsDRI is 5 g/day (ages 1950) for
both males and femalesDRI is 10 g/day (ages 5170) for both males
and females20Vitamin KNecessary for blood coagulationControls
formation of coagulation factors II, VII, IX, and X in the
liverAlso needed for calcium uptake in bonesCan be used as an
antidote for coumadin overdosesDeficiency is rareDRI is 120 g/day
for males and 90 g/day for females21Vitamin B1 (thiamine)Necessary
for carbohydrate metabolismDeficiency causes the disease
beriberiAffects the peripheral neurologic, cerebral,
cardiovascular, and GI systemsDRI is 1.2 mg/day for males and 1.1
mg/day for females22Vitamin B3 (niacin)Important in
oxidation-reduction reactionsVital in protein metabolismDeficiency
leads to the disease pellagra:Affects skin, mucous membranes, GI,
and brain/CNS systemsCauses photosensitive rash, scarlet
stomatitis, glossitis, diarrhea, and mental aberrationsDeficiency
found in diets high in cornDRI is 16 mg/day for males and 14 mg/day
for females
23Vitamin B6 (pyridoxine)Needed for:Red blood cell formation-
Antibody productionCell respiration- Cell growthConversion of
tryptophan to niacinHelps convert stored carbohydrate to glucose to
maintain normal blood sugar levelsSynthesis of neurotransmitters
such as serotonin and dopamineDeficiency can cause:Anemia similar
to iron-deficiency anemiaDecreased antibody productionSuppressed
immune responseSymptoms such as dermatitis, a sore tongue,
depression, confusion, and convulsions
24Vitamin B9 (folic acid)Important for:Energy
production-Formation of red blood cellsStrengthening immune
systemPromoting healthy cell division and replicationProtein
metabolismPreventing depression and anxietyDeficiency can be
serious and may result in:Anemia- ApathyDigestive disturbances-
FatigueGrowth impairment- InsomniaLabored breathing- Memory
problemsParanoia- Weakness
25Vitamin B12 (cyanocobalamin)Needed for healthy nerve cells, to
make DNA, and for the formation of RBCsDeficiency leads to
irreversible nerve damageSigns and symptoms include:Fatigue-
weaknessNausea- constipationFlatulence- loss of appetiteweight loss
- depressionConfusion- poor memory
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