This document discusses drug interactions, which occur when one drug alters the effects of another drug. It defines different types of drug interactions including drug-drug, drug-food, drug-alcohol, drug-disease, and drug-laboratory interactions. It also describes pharmaceutical interactions that can be chemical or physical reactions between drugs. Pharmacological interactions are classified as pharmacodynamic or pharmacokinetic. Pharmacodynamic interactions directly influence drug effects, while pharmacokinetic interactions alter a drug's absorption, distribution, metabolism, or excretion. The document advises telling healthcare providers about all medications and supplements to avoid dangerous drug interactions.

1. BY
ASAWE TEJASWINI L
DEPARTMENT OF PHARMACOLOGY
ASSIASTANT PROFESSOR
SIDHHIS INSTITUTE OF PHARMACY
THANE
Drug Interaction

2. • A drug interaction has occurred when administration of
one drug alters the clinical effects of another .
• A drug interaction results when the effects of a drug are
altered in some way by the presence of another drug, by
food, or by environmental exposure.
• A drug–drug interaction increases with the number of
medications a patient is receiving can cause risk of
developing an adverse drug reaction (ADR).
Drug interaction

4. Drug – Drug Interaction
 A reaction between two or more drugs.
 This can involve prescription medications , over
the counter medicine (OTC) and herbs, vitamins ,
and supplements.
 Taking a drug while having certain medical
conditions can also cause a drug interaction.
 For example, taking a nasal decongestant if you
have high blood pressure may cause an
unwanted reaction.
 Warfarin ( prevent blood clots) with acetylsalicylic
acid (anti-inflammatory) may increase the risk of
bleeding.

5.  A drug-drug interaction (DDI) occurs
when the clinical effect of a given drug is
altered by the action of another drug.
 Importantly, drug interactions contribute
to the majority of adverse drug
reactions, and approximately 70% of
interactions are clinically relevant.

6. Drug Food Interaction
 When food or beverage intake alters a drugs
effect.
 If someone taking certain statins atorvastatin ,
rosuvastatin to lower cholesterol & drinks a lot of
grapefruit juice can cause too much of drug in
body.
 This may increase their risk for liver damage or
kidney failure.
 Ex. ANTIBIOTICS with milk products that complex
with some antibiotics and prevent their
absorption. reduced bioavailability

7. Drug – Alcohol Interaction
 Certain medication should not be taken with
alcohol.
 Combination of alcohol with drugs can cause
tiredness and delayed reactions, can also your risk
for negative side effects.
 Ex. drug interaction between warfarin and alcohol,
which could increase bleeding risk.
 medications can interact with alcohol, including
antibiotics, antidepressants, muscle relaxants,
anti-inflammatory agents and warfarin.

8. Drug - Disease Interaction
 The drugs that alters or worsen a condition or
disease.
 Ex. taking a nasal decongestant for cold can
increase blood pressure .
 This is potentially dangerous dangerous
interaction for people with high blood pressure
may cause an unwanted reaction.

9. Drug Laboratory Interaction
 Medication interferes with laboratory test.
 This can result in inaccurate test.
 For example, cephalosporin's may alter urine
glucose and ketone tests.
 Certain antidepressants have been shown to
interfere with skin prick test used to determine
allegy.

10. DRUG INTERACTION
PHARMACEUTICAL
(OUTSIDE THE BODY )
PHARMACOLOGICAL
(INSIDE THE BODY
PHYSICAL
CHEMICAL
PHARMACODYNA
MIC
PHARMACOKINE
TIC
ANTAGONIS
T
ADDITIVE
SYNERGIST
IC
ABSORPTIO
N
DISTRIBUTIO
N
METABOLIS
M
EXCRETION

11. Pharmaceutical Interaction
 Pharmaceutical interaction can be divided into
chemical and physical reaction.
 A chemical reaction is occurs due to the
incompatibility between two drugs administered at
the same time.
 Ex. phenytoin and lorazepam become ineffective
if mixed together in the same IV bag or syringe.
 Physical reaction occurs when physically altering
a drug formulation such as by crushing a
sustained release tablet , drug release more
quickly and in large amount.

12. Pharmacological Interaction
 Pharmacological Interaction most commonly occurring in
drug -drug interaction.
 Pharmacological interaction are classified as
pharmacodynamic & pharmacokinetic interaction .
 Pharmacokinetic interactions results from alteration in a
drugs absorption , distribution , metabolism and excretion
characteristics.

13. Pharmacodynamic interactions
 Pharmacodynamic interactions are those in which one drug influence
each others effect directly .
 Such interactions are of particular importance when chemotherapy
drugs that are nephrotoxic are combined.
 An additive Pharmacodynamic effect when two or more drugs with
similar Pharmacodynamic effect are given , the additive effect may
result in excessive response and toxicity .
 additive Pharmacodynamic effect When on the kidneys can lead to
mild-to-moderate renal failure.
 Antagonistic Pharmacodynamic effect may reduce response to one or
both drug .
 Ex when acetylsalicylic acid combined with ibuprofen it reduced the
drug effect .

14. Pharmacokinetic interaction
 pharmacokinetic interaction occurs when one medication alters
the absorption, distribution, metabolism, or excretion of another.
 The effect of other drugs or non medicinal products on the
amount of chemotherapeutic drug absorbed is especially
important in the case of orally administered drugs.
 Food intake may increase or decrease these drugs' absorption.
 For example, it is important that capecitabine be taken within 30
minutes after a meal.
 The safety of capecitabine taken on an empty stomach has not
been established.
 When pharmacists dispense prescriptions for these agents, it is
essential that they make patients aware of the effect or food or
drugs.

15. How can a person avoid drug
interactions?
 You can take the following steps to avoid drug
interactions:
 Tell your health care provider about all prescription and
nonprescription medicines you are taking or plan to
take.
 Also tell your health care provider about any vitamins,
nutritional supplements, and herbal products you take.
 Tell your health care provider about any other
conditions you may have, such as high blood pressure
or diabetes.
 Take medicines according to your health care provider's
instructions.
 Always read the information and directions that come
with a medicine.

16. Thank You