Synergism and Antagonism.pptx Basic level

Basic concepts of the term

1. General Pharmacology

2. Name: Miss Noor Afzal Designation: Demonstrator Department: DEAHT E-mail: [email protected] Week no: 12: Synergism and Antagonism

3. SYNERGISM AND ANTAGONISM PHENOMENON OF DRUG ACTION

4. INTRODUCTION SYNERGISM COMBINED EFFECTS OF DRUGS ANTAGONISM COMPARISON IMPORTANCE Presentation Content:

5. Synergism and antagonism are fundamental concepts in pharmacology that describe how drugs interact with one another, influencing their overall effectiveness and safety profiles. Synergism and antagonism are terms often used in pharmacology, toxicology and other scientific disciplines to describe the interaction between two or more substances or agents. SYNERGISM AND ANTAGONISM INTRODUCTION:

6. When two or more drugs are given simultaneously or in quick succession, they may be either indifferent to each other or exhibit synergism or antagonism. The interaction may take place at pharmacokinetic level or at pharmacodynamic level COMBINED EFFECT OF DRUGS SYNERGISM AND ANTAGONISM NOTE : Pharmacodynamic – It is the study of how a drug affects the body. Pharmacokinetics – It is the study of how the body affects a drug over time.

7. SYNERGISM SYNERGISM AND ANTAGONISM [ GREEK = SYN-together, ERGON-work ] When the action of one drug is facilitated or increased by the other, they are said to be synergetic. In a synergistic pair, both the drugs can have action in the same direction or given alone one may be inactive but still enhance the action of the other when given together. Source : Pharma Helpers, SlideShare 2020

8. SYNERGISM AND ANTAGONISM SYNERGISM SUPER ADDITIVE ADDITIVE

9. SYNERGISM CAN BE SYNERGISM AND ANTAGONISM The effect of the two drug is in the same direction and simply adds up : i) ADDITIVE: Effect of drugs A+B = Effect of drug A + Effect of drug B Example: Aspirin + Paracetamol - as analgestic \ antipyretic Nitrous oxide + Halothene - as general anaesthetic

10. SYNERGISM CAN BE SYNERGISM AND ANTAGONISM The effects of combination is greater than the individual effects of the components. ii) SUPER ADDITIVE: Effect of drugs A+B > Effect of drug A + Effect of drug B Example: Levodopa + Carbidopa - Inhibition of Pheripheral metabolism Adrenaline + Cocaine - Inhibition of neuronal uptake source : Pharma Helpers, slideshare 2020

11. NEXT ANTAGONISM GREEK = ANTI = against, AGONIZESTHAI= to contend for a prize. When the one drug decreases or abolishes the action of another, they are said to be “Antagonist” Usually in an antagonistic pair one drug is inactive as such but decreases the effect of the other. Depending on the mechanisms involved. Effect of drugs A+B < Effect of drug A + Effect of drug B SYNERGISM AND ANTAGONISM

12. SYNERGISM AND ANTAGONISM ANTAGONISM PHYSICAL ANTAGONISM CHEMICAL ANTAGONISM PHYSIOLOGICAL ANTAGONISM RECEPTOR ANTAGONISM COMPETITIVE ANTAGONISM NON-COMPETITIVE ANTAGONISM

13. ANTAGONISM CAN BE SYNERGISM AND ANTAGONISM Based on the Physical property of the drugs. i) PHYSICAL ANTAGONISM: Example: Charcoal absorbs alkaloids - Used in alkaloidal poisoning ii) CHEMICAL ANTAGONISM: The two drugs reacts chemically and form an inactive products.

14. SYNERGISM AND ANTAGONISM Examples of Chemical antagonism KMno4 oxidizes alkaloids - used for gastric lavage for poisoning Tannis + alkaloids - insoluble alkaloids tannate is formed Chelating agents (BAL, Cal, disod.edetate) complex toxic metals (As, pb) Nitrites form methaemoglobin which reacts with cyanide radical. Drugs may react when mixed in the same syringe or infusion bottle. Thiopentone sodium + Succinylcholine chloride Penicillin-G sodium + Succinylcholine Chloride Source : Amol B. Deore , 2020

15. SYNERGISM AND ANTAGONISM The two drugs act on different receptors or by different mechanisms, but have opposite oven effects on the same physiological functions, i.e., have pharmacological effects in opposite direction iii) Physiological \ Functional antagonism Example: Histamine & Adrenaline on bronchial muscles & BP Glucagon and Insulin on blood sugar level.

16. SYNERGISM AND ANTAGONISM iv) Receptor Antagonism: One drug ( an-antagonic ) blocks the receptor action of the other ( agonist ) This is a very important mechanisms of drug action, because physiological signal molecules act through their receptors, blockage of which can produce specific and often profound pharmacological effects. Source : Pharma Helpers, slideshare 2020

17. a) COMPETETIVE ANTAGONISM The antagonist is chemically similar to agonist, competes with it and binds to same size. Antagonist has no capacity to produces response Example : Morphine (Drug) + Naloxone (competive antagonist) SYNERGISM AND ANTAGONISM source : Pharma Helpers, slideshare 2020

18. SYNERGISM AND ANTAGONISM The antagonist is chemically unrelated to the agonist, binds to allosteric size and alter one receptor in such a way that it is unable to combine with the agonist or unable to produce response. b) NON COMPETETIVE ANTAGONISM: NMDA Receptor -----> Keramine source : Pharma Helpers, slideshare 2020

19. SYNERGISM AND ANTAGONISM This is also called allosteric antagonism Because the agonist and the antagonist are combining with different sizes, there is no competition between them - even high agonist concentration is unable to reverse the block completely. Non Competitive antagonist have been produce experimentally, but are not in clinical use. Source : Alex Yatsev et al 2015

20. NEXT COMPARISION SYNERGISM AND ANTAGONISM SYNERGISM ANTAGONISM i) Impact on dosage Can lead to a lower require dose of each drug to achieve the desired therapeutic effect, potentially reducing side effect. i ) Impact on dosage Often requires higher dose of one or both drugs to achieve the desired effect if one drug diminishes the effectiveness of the other. ii) Clinical outcome Typically results in enhanced therapeutic outcomes and improved efficacy of treatment. ii) Clinical outcome May lead to reduced effectiveness of therapy, necesitating alternative treatments or aejustments.

21. SYNERGISM AND ANTAGONISM SYNERGISM ANTAGONISM iii) Drug interaction type Often involves drugs with icomplementary mechanisms of actions or different targets, enhancing overall therapeutic efficacy. Involves drugs that have opposite effect on the same physiological system or receptor, cioncentrating each other’s actions. iii) Drug interaction type iv) side effects May reduce the likelihood of severe side effects by allowing lower doses of each drug iv) side effects May not necessarily reduce side effects but can complicates the therapeutic approach and lead to unwanted interaction or side effects from drug involved v) Drug involved Penicillin and aminoglycosides ( Ex: Gentamicin ) v) Drug involved Beta-Agonists ( Ex: Albuterol) Beta-Blockers (Ex: Propanal )

22. IMPORTANCE OF SYNERGISM AND ANTAGONISM SYNERGISM AND ANTAGONISM i) Enhanced Therapeutic effects Synergism in drugs, where two or more drugs work together to produce a greater effect than the sum of their individual effects, can improve treatment efficacy and reduce the required doses. This can lead to better patient outcomes and fewer side effects. ii) Reduced Adverse Effects Antagonism, where one drug reduces or nullifies the effect of another, helps in minimizing potential drug interactions and adverse effects. By carefully managing drug combinations, healthcare providers can prevent harmful interactions and optimize treatment safety.