pharmacology - new

8/14/2019 Pharmacology - New

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BASICS

INPHARMACOLOGY


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Sources of Drugs

DRUG

chemicals

plants

microbial

animal

Drug is defined as a substance

obtained from mineral, chemical,animal, microbial or plant sourceswhich is used in the diagnosis,prevention and treatment of diseasein humans and animals.


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Dose & Dosage form

Dose is the quantity of drug given at a time so that it

results in the desired effect, without causing harm Drug is useful when available in a form in which it is

easily handled and given to the patients, e.g.

Capsules

Syrups

Tablets


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Oral

Sublingual

Rectal

Advantages

Most convenient, most economical

Safer compared to parenteral

Self administered

Disadvantages

Irritant, unpalatable

Not useful in vomiting

And unconcious patients

Intramuscular

Intravenous

Subcutaneous

Advantages

Vomiting and diarrhoea and in the patients

unable to swallow

Drugs that might irritate the stomach or

which are not absorbed orally

Rapid action

Accuracy of dose

Disadvantages

Less safe

More expensive

Inconvenient to use, self medication being

difficult

Liable to cause infection

Injure important structures

Topicals

Inhalation

Advantages

Site specific action

Decreased systemic adverse effects

Disadvantages

Local irritation, inconvinience

Routes Of DrugAdministration


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PHARMACOLOGY-

Is the science that deals with the

study of drugs.

Pharmacology

PHARMACOKINETICSPHARMACODYNAMICS

DRUG BODY BODY DRUG


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PHARMACODYNAMICS

DRUG


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PHARMACOKINETICS

DRUG


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PHARMACODYNAMICS

RECEPTORS A Drug Receptor is a specialised

target molecule present on the

cell surface or intracellularly

drug + receptor drug-receptor complex effect

AGONIST activate the receptors when they occupy it Affinity

Good intrinsic activity

ANTAGONIST no activation when they occupy the receptor Affinity

No intrinsic activity


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RECEPTOR DRUG DRUG RECEPTOR

COMPLEX

DRUG RECEPTORCOMPLEX FORMATION


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Agonist Antagonist

Receptor

Drug


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PHARMACOKINETICS


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DRUG ADMINISTERED

PLASMA

DISTRIBUTION IN THE TISSUES

ABSORPTION

DRUG & METABOLITES IN PLASMA

DRUG & METABOLITES IN URINE,

FEACES,BILE

METABOLISM

ELIMINATION


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C max

T max t1/2

AREA UNDER CURVE

Drug given at

this point

Cmax = Maximum drug concentration

Tmax = Time taken to reach Cmax

t1/2 = Half life


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Half Life

Measure of the time elapsed for the plasma

drug concentration to fall to half its original

value (Cmax)

Elimination half life from plasma is clinically

important for safety profiles of drugs


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Renal Faecal

Breast milk

Pulmonary

Saliva & Sweat glands

Sites of Elimination


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Additive Effect

When the total pharmacological action of

Two or more drugs administered together

Is equivalent to the summation of their

individual pharmacological actions

e.g. : Ephedrine + Aminophylline treatment

of bronchial asthma

Pharmacology & Pharmacotherapeutics,

Satoskar;1997: pg 45

1 + 1 = 2


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Synergistic Effect

When the total pharmacological action of

two or more drugs administered together

is more than the summation of their

individual pharmacological actions

e.g. :Cotrimoxazole (Sulphamethoxazole

+ Trimethoprim) Septran

Pharmacology & Pharmacotherapeutics,

Satoskar;1997: pg 45

1 + 1= X (>2)


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OD - Once daily

BD - Twice daily

TD - Thrice daily

QD - Four times daily

SOS - During emergency use

hs - At bed time

Stat - Immediately

Bolus- Amount of drug given as IV at a

controlled but rapid rate

Loading dose- Initial higher dose

Drug Dosing


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PHASE OF A CLINICAL TRIAL

Phase I(max. tolerated dose & safety,comprises of small no. of patients)

Phase II( therapeutic effect )

Phase III(comparative study with the

current standard therapy, comprises of

large no. of patients)

Phase IV / Post-marketing Surveillance(PMS): continuing evaluation that takes

place after FDA approval, when drug or

treatment procedure is already in the

market & available for general use

Clinical Trials


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TH NK YOU

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