Topic 1 - Pharmacodynamics – structure-dependent and structure-independent drug action Flashcards
What is pharmacodynamics?
It explains, together with pharmacokinetics the relationship between the dose and response
Definition of pharmacodynamics
the body’s biological response to the drug
What the drug does to the body
Definition of pharmacokinetics
The movement of drugs through the body
What the body does to the drug
Has an abbreiation which stands for how the given drug interacts within the body over time: ADME
What does ADME stand for?
Absorption
Distribution
Metabolism
Excretion
Definition of absorption
How the drug enterst the body
Does NOT apply for IV
Definition of distribution
Where the drug will go
Definition of metabolism
How drugs are transformed and broken down, takes place in the liver
Definition of excretion
How the drug leaves the body
Key component of pharmacodynamics
- Mechanism of action
- Drug-receptor interactions
- Dose-response relationship
- Therapeutic window
- Potency and efficiacy
- Side effecs and toxicity
- Tolerance and sensitiaztion
Definition of Mechanism of action
Describes how a drug produces an effect
Defintion of Drug-receptor interactions
Describes the binding of receptors to drugs
Definition of Dose-response relationship
Relationship between the drug dose and the drug concentration
Defintion Therapeutic window
The range of drug dosages which can treat the disease efficteciely without having oxic effects
Definition of Potency and efficiacy
Potency = Amount of drug necessary to produce a biological response
Efficiacy = Ability of the drug to produce an response by the actiovation of the receptor
Definition of Tolerance and sensitiaztion
**Tolerance = **The DECREASED effectiveness of a given drug, with repeated administration
**Sensitization = **The INCREASED effectiveness of a given drug, with repeated administration
What is the goal of pharmacodynamics?
To help design and optimizing drug therapies to ensure maximum efficacy and safety for patients
Definition of structure dependent drug action
Effects that rely on the specific chemical structure of the drug. The drugs interact with specific biological targets, such as receptors or enzymes, in a way that depends on their precise molecular shape and chemical properties
Structure dependent drugs rely on their presise chemical structure to interact with specific targets in the body
Give an example of a structure dependent drug:
Beta blockers
The work by fitting into beta-adrenergic receptors (like a key fits into a lock) to block the action of adrenaline, thus reducing heart rate and blood pressure
Definition of structure independent drug action
Effects that do not rely on the specific interaction between the drugs chemical structure and a particular biological target. Instead, these drugs cause a physical and chemical changes in the body that lead to their therapeutic effects
Structure independent drugs produce effects through general physical and chemical changes
Give an example of a structure independent drug:
Antacids
They work by neutralizing stomach acid through chemical reaction, regardless of their specific molecular structure
Name the different interactions with drugs:
Physical interaction
Biochemical interaction
What is physical interaction?
occur most commonly when drugs are combined in IV solutions
Examples of physical interactions:
- Osmotic diuretics = Mannitol Often used for renal failure or kidney damage
- Antacids = Mg(OH)2 - Magnesium hydroxide Used when there is a gastric acid build up
- Laxatives = MgSO4 - Magnesium sulphate
- Chelators = EDTA, deferoxamine Used for lead poisoning or iron overdose
What is biochemical interactions?
Can be with or without receptors, but the target is almost always a protein
