Drugs

Dosa ge

MOA

ADR

USES

Penicillins (Penicillin-G: Benzyl Penicillin)



• All B-lactam antibiotics interfere with the synthesis of bacterial cell wall
• The B-lactam antibiotics inhibit the transpeptidases so that cross linking does not take place
• These enzyme and related proteins constitute penicillin binding proteins (PBPs) which has been located in bacterial cell membrane

• Pain at IM site
• Nausea on oral ingestion
• Thrombophlebitis of injected vein
• Toxicity to brain- mental confusion, muscular twitching, convulsions, coma especially in patient with renal insufficiency
• Bleeding– in high dose due to interference with platelet functions
• Hypersensitivity- rash, itching, urticarial and fever
• Superinfections
• Jarish- Herxheimer reaction- penicillin injected to syphilictic patient particularly secondary syphilis may produce- fever, myalgia, exacerbation of lesions, even vascular collapse. This is due to sudden release of spirochetal lytic products

• Streptococcal infections– Pharyngitis, otitis media, scarlet fever, rheumatic fever
• Pneumococcal infections– pneumococcal pneumonia, meningitis- not used now because of resistance
• Meningococcal infections- still responsive
• Gonorrhea
• Syphilis- Penicillin is DOC
• Diphtheria
• Tetanus and gas gangrene
• Prophylactic use- Rheumatic fever, Bacterial endocarditis, Agranulocytosis patient

Phenoxymethyl Penicillin (Penicillin V)



• It differs from PnG in that it is Acid stable

• Same as above

• It cannot be depended upon for more serious infections
• Used only for– Streptococcal pharyngitis, sinusitis, otitis media, prophylaxis for rheumatic fever

Drug

Dosa ge

MOA

ADR

USES

Penicillinase resistant penicillin (Methicillin, Cloxacillin/ Dicloxacillin,

Oxacillin, Flucloxacillin)



• They have side chain that protect the B-lactam ring from attack by staphylococcal penicillinase

• Methicillin- Hematuria, albuminuria, reversible interstitial nephritis so it has been replaced by cloxacillin

• Only indication is infections caused by penicillinase producing Staphylococci for which they are DOC, except in the areas where MRSA has become prevalent.
• These drug are not resistant to B- lactamase produced by gram negative bacteria

Ampicillin



• Active against all organism sensitive to PnG
• In addition many gram negative bacilli e.g. H. influenza, E. coli, Proteus, Salmonella, Shigella and H. pylori

• Diarrhea frequent after oral administration
• Ampicillin is incompletely absorbed- irritates the lower intestine as well as caused marked alteration in bacterial flora
• Rashes- High incidence
• Hypersensitivity- if hypersensitive to penicillin do not give ampicillin

• UTI
• Respiratory tract infections- Sinusitis, otitis media, bronchitis
• Meningitis
• Gonorrhea
• Typhoid
• Bacillary dysentery
• Cholecystitis
• SABE
• H. pylori
• Septicemia and mixed infections
• ANUG

Amoxicillin



• Congener of ampicillin, similar to it in all respect except:
  • Oral absorption is better
  • Incidence of diarrhea is lower



• Many physician prefer it over ampicillin for bronchitis, UTI, SABE and gonorrhea
• Triple therapy for H. pylori

Drug

Dosa ge

MOA

ADR

USES

Carboxypenicil line (Carbenicillin)



• Active against Pseudomonas aeruginosa and indole positive Proteus which are not inhibited by PnG or aminopenicillins



• Serious infection caused by Pseudomonas or Proteus- Burns, UTI, Septicemia, but Piperacillin is now mostly used

Ureidopenicilli ns (Piperacillin)



• Antipseudomonal penicillin
• 8 time more potent than carbenicillin



• More frequently employed for treating serious gram negative infections in neutropenic/ immunocompromised or burn patients

B-Lactamase Inhibitors (Clavulanic acid) Streptomyces clavuligerus



• It has B-lactam ring but no antibacterial activity of its own
• It inhibits a wide variety (class II to class V) of B-lactamases produced by both gram positive and gram negative bacteria
• But not to class I cephalosporinase

• Same as for amoxicillin alone
• Candida stomatitis/ vaginitis
• Rashes
• Hepatic injury

• Addition of Clavulanic acid reestablishes the activity of amoxicillin against B- lactamase producing resistant Staph. Aureus (but not MRSA), H. influenza, N. gonorrhea, E. coli, Proteus, Klebsiella
• Skin and soft tissue infections
• Intraabdominal and gynaecological

sepsis

• UTI
• Biliary and Respiratory tract infections– in hospital acquired settings
• Gonorrhea

Drug

Dosa ge

MOA

ADR

USES

Sulbactam



• Semisynthetic B-lactamase inhibitor
• Related chemically as well as in activity to clavulanic acid
• Active against class II to V but not Class I B lactamase
• 2-3 time potent to clavulanic acid

• Pain at site of injection
• Thrombophlebitis of injected veins
• Rash
• Diarrhea

• Oral absorption is inconsistent so preferably given Parenterally
• Combined with ampicillin for use against B-lactamase producing resistant strains
• N. gonorrhea
• Mixed aerobic and anaerobic infections, intraabdominal, gynaecological, surgical
• Skin/ soft tissue infections, especially those acquired in hospital

Tazobactam



• Similar to sulbactam

• Same as clavulanic acid

• PK matches with piperacillin so combined with it for used in severe infections caused by B-lactamase producing bacilli-
  • Peritonitis
  • Pelvic/ urinary/ respiratory infections
• However combination not active against Piperacillin- resistant Pseudomonas