vety chemotherapy crash course notes

7/28/2019 Vety Chemotherapy crash course notes

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CHEMOTHERAPY


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Problems arises with use antimicrobial drugs are

1.Toxicity

2.Resistance3.Superinfection

Combination of drugs

Cidal+cidal = synergistic(sulpha+TMP)

Cidal+static = AntagonisticStatic+static =Additive

Post antibiotic effect high with aminoglycosides

Biphasic effect Quinolones

Synthetic AMASulphonamides :-structural similarity with PABA

MOA:-Inhibit Folic acid synthesis,competitive inhibition of PABA


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Classification

1.Systemic:-

Short acting:-Sulphadiazine,Sulphamerazine,Sulphathiazole

Intermediate acting:-

Sulphadimidine,Sulphamethoxazole,Sulphaphenazole

Long acting:-

Sulphadimethoxine,Sulphaethoxypyridazine,Sulphabromethazine

2.GUT ACTING

Phthalyl sulphathaizole,Succinyl sulphathiazole,Sulphaguanidine,

Sulphasalazine

3.TOPICAL SULPHONAMIDEMefinide,Silver sulphadiazine

4.OPHTHALMIC :-

Sulphacetamide


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TOXICITY:- crystallurea

Potentaited sulphonamides:-

Sulphamethoxazole+Trimethoprim(5:1) combination results insequential blockade of folic acid synthesis.

Trimethoprim inhibit conversion of DHF to THF by inhibiting

enzyme THFR

Quinolones:-1st generation :- Nalidixic acid(narrow spectrum)

Flouroquinolones(Broad spectrum):-

Norfloxacin,Ciprofloxacin,Pefloxacin,Marbofloxacin,Orbi,Enro,Da

nofloxacinVeterinary use:-Enrofloxacin

MOA:- Inhibit DNA gyrase enzyme

Toxicity:- Joint arthropathy


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NITROFURANS

Nitrofurazone,Nitrofurantoin,Furazolidone,

MOA:- Inhibit energy metabolismUsed topically

BETALACTAM ANTIBIOTICS

Penicillins,Cephalosporins,lactamase inhibitors,other lactam

antibiotics

MOA:-Inhibit peptitoglycan synthesis there by inhibiting the cell

wall synthesis

Classification:-

1)Natural penicillin:-Benzyl penicillin,Acid resistant:-Penicillin V

2)Semisynthetic Penicillin:-Penicillinase resistant penicillin

Eg:- Oxacillin,Cloxacillin,Methicillin,Naficillin


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3)Broad spectrum Penicillins:-

Ampicillins,AmoxycillinProdrugs of Ampicillin:-Hetacillin,Becampicillin,Talampicillin

4)Others:- Mecillinam(Amidocillin only for Gram negative bacteria)

Extended spectrum :- Carbencillin,Ticarcillin

5) Beta lactamase inhibitors/Potentiated penicillins

Clavulanic acid(Suicide inhibitors)

Amoxycllin+ Clavulanicacid:- AUGMENTIN

Sulbactam

Tazobactam


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CEPHALOSPORINS

1st Generation:- Cephalothin,Cefazolin,Cephalexin,Cefedroxil

2nd generation :- Cefuroxime,cefaclor,Cefomandol

3rd generation:-Cefotaxim,Ceftiofur,Cefopearzone,Ceftriaxone

4th generation :- Cefepime,Cefperome

CARBAPENEMS

IMIPENEM:-Most broad spectrum lactam antibioticCilastatin inactivates Renal dehydropeptidase there by prevent

deactivation of imipenem

Meropenam:- No need of cilastatin

MONOBACTAM

Aztreonam-Gram negative enteric bacilli


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AMINOGLYCOSIDES

Streptomycin:-Waksman 1944- from Streptomyces griseus

Gentamicin-Micromonospora purpurea

Kanamycin- Streptomyces kanamyceticus

Tobramycin-S.tenebrarius

Amikacin:- Semisynthetic from KanamycinSisomicin-Micromonospora.inyonensis

Netilmicin Semisynthetic from Sisomycin

MAO:-Inhibit 30S ribosomal subunits-Misreading of mRNA

codone

Toxicity:- Nephrotoxicity,Ototoxicity,NM blockade


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TETRACYCLINS

S.Aureofaciens:-Chlortetracyclins

Broad spectrum more active against Gram positive bacteriaShort acting:-Oxytetracyclins,Chlortetracyclins

Intermediate acting :-Demeclocyclins

Long acting:- Doxycyclins,Minocyclins

MOA:- Inhibit protein synthesis by inhibiting 30S ribosomal

subunit

Side effects:- Superinfection,irritation,Calcium

chelation,Hypotension


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CHLORAMPHENICOL

S.Venezualae, Bacteriostatic,Broad spectrum, Highly lipid soluble.

MOA:-Inhibit protein synthesis Bind with 50S ribosomal unit

Toxicity

Aplastic Anemia(Para nitro group)

Less toxic Thiamphenicol,Floufenicol

MacrolidesErythromycin- S.erythreus

Broad spectrum

Azithromycin,Dirithromycin,Roxithromycin,Tilmicosin,Tylosin

MOA:- Inhibit protein synthesis by inhibiting ribosomal subunit

Oleandrmycin,Troleandromycin


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LINCOSAMIDES AND MONOGLYCOSIDES

MOA:-Inhibit protein synthesis by inhibiting 50S ribosomeSide effect:- Psuedomembraneous colitis bu cl.difficile

MISCELLANEOUS

Polymixin:- B.polymyxa

Vancomycin:-GlycopeptideRifamycin:-S.mediterranei(gram ve)

Rifampicin:-Semisynthetic rifamycin

MOA:- inhibit DNA dependant RNA polymerase,Gram positive

bacteria


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ANTHELMINTHICS

Antinematodal

1)Benzimidazoles- Thiabebdazole,Albendazole,fenbendazoleMOA:- Inhibit polymerisation of tubulin ,Inhibit fumerate

reductase

2)Benzimidazole prodrugs:- Febantel,Netobimin,Thiophanate

3)Macrocyclic lactones:- Ivermectin,DoramectinMOA :-Binds glutamate gated chloride channels

4) Imidazothiazoles:- Tetramizoles,Levamisole

MOA :- Stimulate aaans-susained muscle contraction

5)Tetrahydropyrimidines:-Pyrantel,Morantel

MOA:-Neromuscular blocking agents


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6)Piperazines(GABA agonists):- Piperazine,DEC

7)Miscellaneous:- Phenothiazines

ANTICESTODAL

1)Isoquinolones:- Praziquantel,epsiprantel

MOA:- Interfering with regulation of calcium concentration

2)Salicylanides :- NiclosamidesMOA:- Inhibit oxidative phosphorylation

3)Substitiuted phenols:-Dichlorphen

MOA :-Inhibit oxidative phosphorylation

4)Benzimidazoles

5)Natural agents:- Kamala(Mallotus philippensis),Arecolin


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ANTI TREMATODAL DRUGS

1)Substitiuted phenols:-Dichlorphen,Nitroxynil,Bithional

2)Salicylanides :- Niclosamide,Closantel,Rafoxanide,Oxyclosanide3)Aromatic amides:-Deamphenitide

MAO:-Vaculation of tegument ogfmparasite

vety chemotherapy crash course notes

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