Enteral Routes

Question 1

Enteral drug administration

Answer 1

Involves absorption of the drug via the GI tract

Question 2

Enteral drug administration via created tracts examples:

Answer 2

Nasogastric (reaching/supplying stomach via nose)
Nasojejunal (soft tube put in through nose that goes through stomach and ends in jejunum, part of small intestine )
Gastronomy (surgical procedure used to insert a tube for feeding/vent stomach for air/drainage)
Jejunostomy (surgery to create opening into sejunum)

Question 3

Sub-lingual administration

Answer 3

Under the tongue

Question 4

Buccal

Answer 4

Given between gums/inner lining of mouth check

Question 5

GTN spray is used to treat? given via what route?

Answer 5

Angina via sub-lingual

Question 6

Amylase

Answer 6

Break down carbohydrates

Question 7

Lipase

Answer 7

Break down/ fat digestion

Question 8

Mouth has pH of?

Answer 8

6

Question 9

Drug goes to the oesophagus by?

Answer 9

Peristalsis - (series of wave-like muscle contraction that move food through the digestive tract)

Question 10

Layers of the stomach and small intestine

Answer 10

Mucosa- lots of vili which increase SA
Submucosa
Muscle
Serosa

Question 11

Pancreatic secretions contain alot of bicarbonates for?

Answer 11

Reducing acidity

Question 12

Most drugs absorbed in?

Answer 12

Small intestine

Question 13

Large intestine is responsible for?

Answer 13

Forming the remanence into faeces, which will then be excreted by the rectum and then the anus

Question 14

Transcellular transfer of nutrients/drugs:

Answer 14

Paracellular
Diffusion through lipidmembrane/aqueous channels
Membrane transporter

Question 15

Lipid solubility of a drug is dependent on?

Answer 15

Ionisation of molecules which is dependent on pH of the body fluid that the drug is in

Question 16

Venous drainage from stomach and intestines goes into?

Answer 16

Portal vein, which then goes into the liver

Question 17

First pass metabolism

Answer 17

When drug is metabolised in liver before going into systemic circulation

Question 18

Lower third of rectum drains by middle and interior rectal veins. Why is this important for drugs given via rectal route?

Answer 18

Drain directly into the systemic circulation, bypassing the hepatic portal circulation

Question 19

Majority of drugs absorbed in gi tract will pass through?

Answer 19

The liver

Question 20

Enterohepatic recirculation

Answer 20

Process by which biliary excreted drug is reabsorbed in the intestine instead of being removed from the body. Can result in a lagging secondary absorption process and increases in drug absorption

Question 21

For drugs with hepatic elimination, may be immediately excreted where?

Answer 21

In bile, then may be reabsorbed

Question 22

Examples of enteral formulations

Answer 22

Tablet, capsule, liquid, foam, water, suppository (administer through rectum), granules, lozenges

Question 23

Final stage in production of a medicine

Answer 23

Drug formulation (combining the active molecule with other molecules)

Question 24

Difference in absorption of drugs administered by oral, buccal, sublingual and rectal routes

Answer 24

Oral- most absorbed in small intestine
Buccal, sublingual and rectal-direct absorption from check into systemic circulation

Question 25

Drug factors

Answer 25

Concentration —> higher dose= higher/faster absorption
Formulation
Molecular size
Other properties - lipid solubility, pH

Question 26

Gastrointestinal factors

Answer 26

-Motility affected by peristalsis
-Blood supply–> if low = less absorption into systemic circulation
- absorption surface
-Gastric content ( some drugs need food /empty stomach) + some drugs taken at the same time may interact
-Bile
- enteric bacteria ( gut bacteria = activate/inactivate drug)

Question 27

enteral drug administration can be via:

Answer 27

oral
direct absorption
via created tracts

Question 28

enteral drug administration via direct absorption: examples

Answer 28

rectal
buccal
sub-lingual

Question 29

What is responsible for the initial breakdown of food and drugs?

Answer 29

mouth

Question 30

Mouth contains what to help with breakdown of food and drugs?

Answer 30

saliva contains enzymes such as : amylase and lipase

Question 31

Pathway of food/ drug to stomach

Answer 31

-Mouth responsible for initial breakdown of food/drugs
-drugs goes to the oesophagus via peristalsis
-drug ends up in the stomach where it is broken down by stomach acid

Question 32

stomach acid pH? why?

Answer 32

1-3
protect against pathogens that cause infection & start denaturing proteins

Question 33

bile emulsifies fat which is important for?

Answer 33

lipid soluble nutrients, drugs or vitamins

Question 34

After drug absorption in small intestine, substance goes to where?

Answer 34

ileum –> large intestine —> rectum—> anus

Question 35

Cellular physiology of small intestine

Answer 35

mucosal epithelium
intestinal villi
Transcellular transfer of nutrients/drugs

Question 36

why is pH important?

Answer 36

for drug movement across the membrane: lipid solubility is dependent on ionisation of molecules which is in turn dependent on pH of the body fluid the drug is in

Question 37

significance of portal circulation:

Answer 37

drugs can be hepatic metabolism or hepatic elimination

Question 38

How ca motility affect the GI

Answer 38

if motility is slower, drug sitting in the lumen for longer –> need more time for it to absorb