january 8 50_conference drug interaction

8/2/2019 January 8 50_Conference Drug Interaction

1/21

DRUG INTERACTIONS

Guided by

Mr.pavan

Presented by

G.nandiniRoll-no

01709014


2/21

Drug interaction

Drug interaction can be defined as themodifications of the effects of one drug by the prior

or concomitant of another drug

The potential drug interactions has been

observed to be 17% in surgical patients, 22% in

patients in medical wards, 23% in out patients

clinics.


3/21

1 in 107 1 in 106 1 in 105 1 in 104 1 in 103 1 in 102

Lightning

Plane crash Murder

Auto-cash

Fatal, unexpected

drug reaction

Increasing risk of death


4/21

Mechanism of drug interaction

Pharmacokinetic interactions Absorption

Distribution

Biotransformation***

Excretion

Pharmacodynamic interactions Receptor interaction

Receptor sensitivity

Drug transportation

Electrolyte balance

Physiological interactions

Pharmaceutical interactions


5/21

Absorption interactions

Where the absorption are the object drug is altered

The net effect of such an interaction is:

Faster or slower drug absorption

More,or,less complete drug absorption


6/21

The distribution pattren of the object drug is altered

The major mechanism for distribution interaction is alteration is

protein

drug binding

Distribution interaction


7/21

Drug metabolism interaction

Enzyme inducers :increase metabolism ofconcomitant drug therefor increase drug

elimination and decrease drug effect

Barbiturate, Rifampin, Phenytoin

Enzyme inhibitors : decresae metabolism

of concomitant drug therefor decrease drugexcretion and increase drug effect

Cimetidine, Ketoconazole, Erythromycin


8/21

Excretion interaction

The excretion pattren of the object drug is altered

Major mechanism of excretion interactions are-

Alteration in renal flood flow

Alteration of urine pH


9/21

Pharmacodynamic interactions

Receptor interaction

Competitive

Non-competitive Sensitivity of receptor

Number of receptor

Affinity of receptor

Drug transportation

Electrolyte balance


10/21

Physiological interactions

Drug A and Drug B bind to different receptors onthe same tissue but give opposite or similar

effect

Aspirin (anti-platelet)+Warfarin/Coumarin (anticoagulant)

Increase bleeding


11/21

Pharmaceutical interactions

Chemical or physiological interactions

Vitamin C + amphotericin B Pennicilin + Vitamin C


12/21

Drug-Drug interaction may alter drug effect by

Additive effect : 1 + 1 =2

Synergistic effect : 1 +1 > 2

Potentiation effect : 1 + 0 =2

Antagonism : 1-1 = 0


13/21

Drug-Food interactions

Grape seed and cyclosporin

Grape seed and felodipine


14/21

Drug-Herb interactions

Ginko biloba


15/21

St. Johns wort: CYP3A4 inducer


16/21

Drug features associated with potentialinteractions

Narrow therapeutic index :

Phenytoin

Cyclosporine

TheophyllineSharp response curve:

Phenytoin

Aminoglycoside

VancomycinDose dependent (Michaelis-Menten) kinetic

Phenytoin


17/21

List of drug the most commoninteracting drug

Antacids

Cimetidine

Digoxin

Warfarin

Theophylline

Ketoconazole


18/21

Problem in medical practice

Possible reasonsPhysiological factors Pathological factors Food

Drug interactionGenetic

D t bl t


19/21

i

Drug tablet

Drug in blood

Drug in tissues

Drug at receptor

Drug metabolites Drug in urine/bil

Desired response No response Unwanted response

Drug interaction

Release

Drug in gut

Absorption

Distribution

Pharmacokinetics

Pharmacodynamics


20/21

CONCLUSION

TodayDrug A

Drug B

Drug CDrug D

Individual physician experience

Cost: time, money & well-being

FuturePatient genetic

s profiles

Drug ADrug B

Drug CDrug D

Informed physician diagnosisSaving : time, money & patients life


21/21

REFERENCES

D.M. BRAHMANKAR

SATHOSKAR

The George Mateljan

Fellers PJ, Nikdel S, Lee HS

K, Iyer KR, Hayes RN, Sinz MW, Woolf TF, Hollenberg PF

J. Thomas

A. David Rodrigues

Barrie R. Cassileth, Charles D. Lucarelli

january 8 50_conference drug interaction

Documents