ABSORPTION Flashcards

(47 cards)

1
Q

Absorption definition

A

Transfer of drug from site of administration to systemic circulation

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2
Q

Types of factors that can affect absorption

A
  • Factors related to drug

- Factors related to patient

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3
Q

Examples of factors related to drug absorption

A
  • Size of the drug
  • Water and lipid solubility
  • Ionization
  • Nature of drug and its molecular weight
  • Valency
  • Preperation and dosage form
  • Rate of disintegration
  • Excipients
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4
Q

Drugs must be water/lipid soluble?

A

DRUGS MUST ME WATER AND LIPID SOLUBLE

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5
Q

Increasing lipid solubility, increases …..

A

Absorption

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6
Q

If the drug is insoluble in water it is …….

A

NOT absorbed

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7
Q

Lipid soluble drugs are ionized/non-ionized?

A

NON-IONIZED

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8
Q

Inorganic drugs have …….. molecular weight

A

SMALL

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9
Q

Organic drugs have …….. molecular weight

A

LARGE

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10
Q

Which iron ion is absorbed more?

A

Ferrous iron (Fe2+)&raquo_space;»» Feric iron (Fe3+)

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11
Q

Dosage form:

A

Solution&raquo_space; Suspension&raquo_space; Tablets

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12
Q

………. has a rapid rate of disintegration

A

Paracetamol

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13
Q

……… has a slow rate of disintegration

A

Digoxin

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14
Q

Calcium carbonate decreases the absorption of ……..

A

tetracycline

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15
Q

Factors related to patient that affect drug absorption:

A
  • Route of administration
  • Absorbing surface
  • Systemic circulation
  • Specific factors
  • Other drugs
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16
Q

Route of adminstration with decreasing absorption rate:

A

IV > IM > SC > Oral > skin

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17
Q

Surface area with descending absorption rate

A

Alveoli > Intestine >Stomach

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18
Q

Absorbing surface with decreasing vascularity:

A

Alveoli > Muscle > SC

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19
Q

When does systemic circulation have low absorption rate?

A

In shock or heart failures as blood flow to skin and muscles decreases

20
Q

How to increase absorption of Vitamin B12

A

Increase secretions of intrinsic factors from the stomach

21
Q

Effect of adrenaline on local anesthetics

A

Causes vasoconstriction so decreases absorption

22
Q

Drugs that increase gastric emptying

A

Metoclopramide

23
Q

Drugs that decrease gastric emptying

24
Q

Effect of metoclopramide on absorption rate

A

Metoclopramide increase gastric emptying so increase rate of absorption of drugs with rapid disintegration rate (paracetamol) and decrease rate of absorption of drugs with slow disintegration rate (digoxin)

25
Effect of Atropine on absorption rate
Atropine decrease gastric emptying so decreases rate of absorption of drugs with rapid disintegration rate (paracetamol) and increases rate of absorption of drugs with slow disintegration rate (digoxin)
26
Events that decrease oral absorption
- Diarrhea - Malabsorption - Decreased gut motility by morphine
27
RULE: The drug is absorbed in the .... media and excreted in the .... media
SAME......OPPOSITE
28
How pH can increase absorption rate
Acidic media in the stomach increases absorption of acidic drugs like asprin and barbiturates Alkaline media in the intestines increases absorption of alkaline drugs like atropine, morphine, ephedrine and amphetamine
29
Where is tannic acid found
In TEA
30
How can the absorption of iron be lowered
By the presence of tannic acid
31
What interferes with the absorption of tetracycline?
Calcium in milk
32
What chemicals decreaes rate of absorption of most drugs
Cholestyramine and charcoal
33
Amino acids compete with ...... and ......... its absorption
Levodopa ........ decreases
34
Irritant drugs may be given after food like
Asprin and iron
35
Synonyms of first pass metabolism
First pass effect | Pre-systemic metabolism
36
First pass metabolism definition
Drug metabolism before it reaches systemic circulation whereby the concentration of the drug is greatly reduced. It takes place after absorption from the GIT in the portal circulation
37
Barriers where drug concentration decreases in first pass metabolism
- Gut first pass - Gut wall - Hepatic first pass
38
Drugs that are destroyed during gut first pass
Penicillin is destroyed by gastric acidity | Hormones and proteins (insulin) are destroyed by gastric enzymes
39
Drugs that can't pass through the lumen
L-DOPA, methyldopa, tyramine
40
L-DOPA is used to treat ....
Parkinson's disease
41
Drugs that pass through the liver and are destructed by its enzymes in the hepatic first pass:
Nitroglycerine, Morphine, Propranolol, Natural sex hormones and lidocaine
42
Nitroglycerine is used to treat
Angina
43
To overcome hepatic first pass:
- Increase oral dose | - Use other route
44
Bioavailability definition:
The fraction of administered drug that reaches the systemic circulation in an unchanged form
45
Factors affecting the bioavailability of the drug:
Absorption rate and first pass metabolism
46
Bioavailability is .....% after IV route
100
47
Bioavailabilty formula for other routes that IV
Bioavailability of a route (F) = | (Area under curve (AUC)of the route / Area under curve (AUC)of IV) x 100