Science of drug which deals with interaction of exogenously administered chemical molecules with living system.
(What the drug does to the body)
Physiological and bio-chemical effect of drugʻand their mechanism of action at macro molecular or sub cellular or organ system level
(What the body does to the drug)
Movement of the drụg and alteration of the drug by the body. It includes absorption, bio transformation and excretion of the drug
(Drogue = dry herb)
A substance which can modify or explore the physiological system (pathological state for the benefits of recipient.
Application of pharmacodynamic information together with knowledge of the diseases.
Clinical pharmacology –
Scientific study of the drug in man. It includes pharmacodynamics
Clinical pharmacology –
Scientific study of the drug in man.. It includes pharmacodynamics and pharmacokinetic investigation.
Treatment of systemic infection/malignancy with specific drug that have selective toxicity for the organism or malignant cells with no or minimal effect on the host cells.
Movement of drug from its side of administration into the circulation.
It is the fraction of administered dose of a drug that reaches the systemic circulation in the unchanged form.
Chemical alteration of the drug in the body. .
First order kinetics –
– Rate of elimination § concentration
– clearance constant
Zero order kinetics
– Clearance §1/concentration
– Rate of elimination = constant
The plasma half life of a drug is the time taken for its plasma concentration to be reduced to half of its original value.
Plateau Principle –
When constant dose of A drug is repeated before the expiry of 4 tys. It should achieve the higher peak concentration.
Ability of the drug to combine with the receptor
(Intrinsic Activity IA)
– Ability of the drug to activate the receptor.
Have both (Affinity and maximum efficacy or intrinsic activity) IA = 1
– Have Affinity and submaximal Intrinsic Activity. (IA = between 0 to 1 )
Inverse Agonist –
Have Affinity but no intrinsic activity/efficacy (IA =0) Agonist – When one drug increases the action of another drugs they are said
Competitive Agonist –
Have Affinity but intrinsic activity with a minus sign (1A = 0 to -1 )
When one drug increases the action of another drugs they are said agonist.
When one drug decrease/inhibit the action of another, they are called Antagonist .
When the action of one drug is increased by the other, it called synergism
Types – (2)
Additive = Effect of drug A + B = Efect of drug A + Effect of drug
B Supra additive = Effect of drug A + B > Effect of drug A + Effect of drug B
Drug Action –
Combination of the drug with its receptors resulting in a conformational change.
Drug Effect :-
It is the ultimate change in biological function brought as a consequences of drug action
Drug Potency – Amount of drug needed to produce a certain action
Drug efficacy – The maximal response that can be elicited by the drug
Dose – Appropriate amount of drug needed to produce a certain degree of response in a patient.