SUI Penicillins
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Transcript of SUI Penicillins
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DR.SHAIKH UBEDULLA,(MBBS,MD,PGDCR,PGDPM)
ASSISTANT PROFESSOR,DEPT OF PHAMACOLOGY,
MMC.
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How an accidental discovery
changed the history of antibiotics!!!
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Sir Howard Florey and Ernst Chain
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The historical landmarks :
28th Sep 1928 Fleming observed the inhibitedgrowth of Staph aureus in the petri dishcontaminated with Penicillium notatum
fungus(Mold juice). 7th Mar 1929 he coined the term PENICILLIN
which is effective against scarlet fever, pneumonia,diptheria but not typhoid , paratyphoid.
1940 : Dr. Howard Florey & Ernst Chain firstpurified Penicillin.
1945 : Mass production started(world war 2) & all 3
got Nobel prize!!24 August 2012
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Chemistry
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Mechanism of action
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Classification
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PENICILLINS
NATURAL
PENICILLIG
SEMISYNTHETIC
ACIDRESITANT
PENICILLINASE RESISTANCE
EXTENDEDSPECTRUM
AMINO
PENICILLINS
CRABOXY
PENICILLINS
UREIDO
PENICILLINS
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PENICILLIN-G (BENZYL PENICILLIN)
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Spectrum of activity
COCCI :
1) Most Streptococci(except viridans)
2) Pneumococci3) Staphylococcus aureus
4) Neisseria gonorrhoeae(Gonococcus) , N .Meningitidis(Menigococcus)
BACILLI :
1) Bacillus anthracis
2) Corynebacteriumdiptheriae
3) Clostridium tetani ,welchii
4) Listeria
5) Spirochetes(Treponema pallidum ,Leptospira)
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Mechanism of resistance
Penicillinase enzyme
Altered in PBP
Loss of or altered porin channels Formation of biofilms
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Bacterial resistance
In generally, there are three main mechanism of -lactam antibiotics resistance.
(1) Nearly all bacteria can produce -lactamase after
contact with -lactam antibiotics. -lactamase caninactivate -lactam antibiotics through rupture the -lactam ring. Different microorganisms produce anumber of distinct -lactamase.
E.g. staphylococci.
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Bacterial resistance
(2) Many bacterial can alter PBPs with decreased
affinity for -lactam antibiotics. This can result in
failure of antibiotics binding to active sites.
E.g. MRSA
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Bacteria Resistance
(3) The concentration of antibiotics in target site is
too low because of lacking of porin protein, such us
OmpF and OmpC. This permeability block isparticularly seen in resistance gram-negative
bacteria that possess a complex outer layer.
Increased active antibiotics efflux which reduce the
drug in bacteria is the other reason for lowconcentration in target site.
E.g. Pseudomonas
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PHARMACOKINETICS
Less than 1/3 rd absorbed orally
Destroyed by gastric acid
Absorption from i.m. site is rapid & complete 60 % Plasma protein bound
Half life 30 mins
Very rapid excretion 90% Tubular secretion & 10 %
Glomerular filtration
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ADVERSE EFFECTS :
LOCAL :
Pain , Thrombophlebitis of vein , irritation.
CNS (High dose):
Confusion , Convulsion , Coma. HYPERSENSITVITY (10 %):
Rash,fever,urticaria,oedema,itching.
Anaphylaxis1-4/10000 pts, often fatal
History of Pen allergy is important
Scratch test / Intradermal test dose (2- 10 U) done first.
RENAL IMPAIRMENT
Dose adjustment is required
OTHERS
Superinfections , Jarisch
Herxheimer reaction24 August 2012
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Unitage of penicillin G
1 U of crystalline penicillin (sod.penicillin G) is equalto 0.6 mcg of standard preparation.
Thus 1 mg = 1667 U1 gm = 1.6 MU
1 MU = 0.6 gm
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Preparations of Penicillin G
Sod.Penicillin G (Crystalline penicillin) injection
Available in dry powder
0.5 -5 MU im/iv
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Preparations of Penicillin G
Procaine penicillin GFollowing deep intramuscular injection, it isslowly absorbed into the circulation andhydrolysed to benzylpenicillin thus it is used
where prolonged low concentrations ofbenzylpenicillin are required.
This combination is aimed at reducing the painand discomfort associated with a large
intramuscular injection of penicillin.
Fortified procaine penicillin G3 lac U procaine pen.+ 1 lac U sod.penicillin G
Rapid as well as sustain release24 August 2012
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Preparations of Penicillin G
Benzathine penicillin G
Intramuscular injection, and hydrolysed tobenzylpenicillin in vivo.
It is the drug-of-choice when prolonged lowconcentrations of benzylpenicillin are required
and appropriate, allowing prolonged antibioticaction over 24 weeks after.
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USES :
1. STREPTOCOCCAL INFECTIONS (Pharyngitis , Otitismedia , Scarlet fever , Rheumatic fever , SABE requirehigh dose)
2. PNEUMOCOCCAL INFETIONS (Lobar pneumonia)
3. MENINGOCOCCAL INFECTIONS
4. GONORRHOEA
5. SYPHILIS
6. DIPTHERIA
7. TETANUS & GAS GANGRENE
8. OTHERS (Anthrax, actinomycosis,Weilsdisease)
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PROPHYLACTIC USES :
RHEUMATIC FEVER :
Benzathine Penicillin 1.2 MU every 4 wks till 18yrsor 5 yrs after attack.
BACTERIAL ENDOCARDITIS :
Pts with valvular heart disease & during Dentalprocedures , Endoscopy , Catherterisation.
AGRANULOCYTOSIS PTS :
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