لخّصلي

Definition of pharmacodynamic: It means the action of a drug on the body, including receptor interactions, dose-response phenomena, and mechanisms of therapeutic and toxic action.Physically: e.g. by adsorption (kaolin and pectin in diarrhea), stool softners in constipation (e.g lactulose), osmosis (osmotic diuretics), etc 2.Example: Aspirin Action of aspirin: block prostaglandin synthesis by inhibiting COX-enzymes.Drugs act by: A. Receptor-binding way (conventional mechanism): most drugs act on receptors.Chemically: e.g. treatment of hyperacidity by NaHCO3 (neutralization of HCL).3.4.5.6.7.

Definition of pharmacodynamic:
It means the action of a drug on the body, including receptor interactions, dose-response phenomena, and
mechanisms of therapeutic and toxic action.
What is the difference between drug action and drug effect?
Drug action = how the drug works and achieves the effect (mechanism of action).
Drug effect = consequences of drug action on the body.
Example: Aspirin
Action of aspirin: block prostaglandin synthesis by inhibiting COX-enzymes.
Effect of aspirin: analgesia & antipyresis.
How do drugs act?
Drugs act by:
A. Receptor-binding way (conventional mechanism): most drugs act on receptors.
B. Non-receptor way (non conventional mechanism).
Non conventional pathways include:

1. Physically: e.g. by adsorption (kaolin and pectin in diarrhea), stool softners in constipation (e.g
   lactulose), osmosis (osmotic diuretics), etc


2. Chemically: e.g. treatment of hyperacidity by NaHCO3 (neutralization of HCL).


3. Interference with cell division: (e.g. some anticancer and antimicrobials).


4. Nutrients: e.g iron, calcium,…


5. Enzymes: streptokinase for thrombolysis.


6. Immunmodulation: e.g vaccines.


7. Unknown mechanisms: e.g general anesthetics.