General Flashcards
Define pharmacology:
Can be defined as the study of substance that interact with living systems through chemical processes
How drugs interact with living systems?
By bindig to regulatory molecule and activating or inhibiting normal body processes.
Drugs porpuse:
It administerated to achieve a beneficial theraputic effect on some process within the patient or for their toxic effects on regulatory processes in parasite infecting the patient
What is a drug?
A drug may be defined as any substance that brings about a change in biologic function through its chemical actions.
Natural Sources of drugs:
Plant: atropin from atropa belladonna, digoxin from digitalis purpurea
Animals: insuline from pork/beef
Minerals: iron, iodine
Microorganisms :penicillin from penicillium nonatum
Synthetic drugs:
Aspirin, steroids, barbiturate
Semisynthetic drugs:
Prepared by modification of natural drug e.g ampicillin from penicillin G
Biosynthetic drug:
Human insulin(humulin) prepared by cloning of human insulin into bacteria (genetic engineering)
Nomenclature of drugs:
Chemical name
Generic name
Trade mark or band name
Dosage forms of drugs:
Tablets
Capsule
Lozenges
Powders
Suppositories
Creams
Ointment
Liquid dosage form:
Ampules : contains one dose of the drug
vials: contains number of doses of the drug
Syrup
Tinctures
Emulsion
Lotion
Drops
Why insulin cant take it orally?
1.it can be destroyed in GIT by peptidase.
2.its first pass metabolism is high and its bioavillability is low
Why insulin has low availability?
Because its first pass mb is high
Systemic Routes of drug administration:
Enteral: oral, sublingual, rectal
Parenteral: inhalational, injection, transdermal
Injections:
I.v, i.m, s.c
Intra-arterial
Intra-articular
Intrathecal
Intradermal
Local routes of administerations:
Skin topical, intranasal, ocular drops, mucosal-throat, vagina, mouth, ear
Inhalation and transdermal inj
Disadvantages of oral route:
Ineffecient for drugs with low solubility
Not suitable for polar drugs
Some drugs destructed in acidic media
Irritation of gastric mucosa
Not suitable in emergencies
It is affected by gastric content and other drugs
First pass effect
First pass effect (presystemic mb)
Term used for hepatic metabolism of a drug when it is absorbed from the gut and delivered to the liver via the portal circulation
E.g for first pass mb in gut:
Benzylpenicillin and insulin
Bioavailability(F):
The term bioavailability is used to indicate the fraction of an orally administered dose that reaches the systemic circulation as intact drug
Factors affecting bioavailability:
Gastric emptying and gastric motility
GIT disease
Food
1st pass mb
Drug-Drug interaction
Surface area of absorption
Route of administeration
Pharmaceutical factors: particle size, salt form, degree of ionization, etc.
Explain why?
Aspirin has bettr absorption in stomach but it is higher in intestine.
Because of the high surface area
E.g of sublingual route
Nitroglycerine
Advantages of suingual route:
Rapid action, rapid absorption
Avoid 1st pass mb
Drug action can be terminated by its removal
