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pharmacology lec 1 Cheat Sheet (DRAFT) by

pharmacology lecture 1

This is a draft cheat sheet. It is a work in progress and is not finished yet.

nature of the drug

- approp­riate size
- electrical charge
-shape
-atomic compos­ition

pharma­cok­inetics (ADME)

Absorption
Distrib­ution
Metabolism
Excretion

oral route

advant­ages**
disadv­antages
easy
slow effect
safe
destru­ction by GIT
self use
first pass effect
convenient
food-drug intera­ction
cheap
drug-drug intera­ction
no need for steril­ization
not suitable for uncurious, emergency

sublingual admini­str­ation

advantages
disadv­antages
rapid effect
not for irritant drugs
no first pass metabolism
high bioava­ila­bility
no GIT destru­ction
bo food-drug intera­ction

parental admini­str­ation

Advantages
Disadv­antages
high bioava­ila­bility
infectious
rapid action
steril­ization
no first pass metabolism
pain
no food-drug intera­ctions
need skill
no gastric intera­ction
anaphy­laxis
suitable for emergency
expensive

inhalation

Advantages
Disadv­antages
Rapid absorption area)
Only few drugs can be used
Rapid effects as IV bolus
Provide local action
Minor systemic effect
low bioava­ila­bility
Less side effects.
No first pass effect
Dosage form: Aerosol, Nebulizer

rectal admini­str­ation

Advantages
Disadv­antages
Vomiting & children. &u­nco­nsc­iou­sness
Irregular absorption & bioava­ila­bility
irritant and bad tasting drugs
Irritation of rectal mucosa
less first pass metabolism
Not a well accepted route
dosage form: suppos­itory or enema

transd­ermal admini­str­ation

Advantages
Disadv­antages
bypass first pass effect
allergy to patches
convenient and painless
drugs must be highly lipophilic
ideal for drugs that are lipophilic and have poor oral bioava­ila­bility
delayed delivery of drugs
 
limited to drugs taken in small daily dosages

topical applic­ation

rate of absorption depends on: physical charac­ter­istics of skin at site of applic­ation and lipid solubility of the drug
 

mechanisms of drug absoption

simple diffusion= passive diffusion
active transport
facili­tated diffusion
pinocy­tosis (endoc­ytosis)

simple or passive diffusion characters

common
occurs along conc gradient
non selective
not saturable
low structural specif­icity
no energy
no carrier is needed
depends on lipid solubility
depends on pKa of drug- pH medium

active transport characters

unusual
occurs against conc gradient
selective
saturable
require energy
carrier is needed (protein)
iron absorption
uptake of levodopa by brain

facili­tated diffusion characters

occurs along conc gradient
selective
saturable
no energy is required
carrier is needed (protein)

factors influe­ncing aborption

1. Effect of pH on drug absorption
2. Blood flow to the absorption site
3. Total surface area available for absorption 4. Contact time at the absorption surface
5. Expression of P-glyc­opr­otein; transm­embrane transp­orter protein. transport drugs from tissue to blood