Archive for the ‘ L4-Antibiotics for Pneumonia ’ Category

L4- Antibiotic Therapy of Lober Pneumonia

What Are the Frequent Causative Organisms Of  Lober Pneumonia ?

TYPES OF PNEUMONIA DRUG

# Antimicrobial

Antibiotic

# Chemotherapeutic  agent

1) ANTIMICROBIALS

Classification

I.    According to mechanism

Picture1

II.  According to antimicrobial activity

Narrow spectrum

Broad spectrum

Wide spectrum

III.According to cidal and static activities

I-Bacteriostatics

1-Macrolides

2-Chloramphenicol

3-Tetracyclins

4-Sulfonamides

II-Bactericidals:

1-Beta Lactams

  • Cephalosporins
  • Penicillins

2-Aminoglycosides

3-Quinolones

4-Rifampicin

Indications of bactericidal agents:

Severe cases

Debilitated patients

Agranulocytosis

Aplastic anaemia

+ Immunosuppression

Factors affecting the antibacterial activity:

I.   Concentration at site of infection

II.   Bacterial resistance

III. Host defense mechanisms

IV. Local factors


How to minimize the emergence of resistance ?

1.High level maintainance

2.A.B. Combinations

3.Use restriction of valuable drug

General adverse reactions:

1.Hypersensitivity reactions

2.Toxic or irritative effects

3.Super infection (opportunistic infection)

4.Organ toxicities

General principals of antimicrobial therapy:

1.When necessary

2. Susceptibility test

3.Consideration of Ph.K. & hepatic and renal states

4.Loading dose & cidality in serious infection

5.Continuation 3 days after apparent cure to avoid relapse

6.Adequate dose & duration & combined therapy to avoide emergence of resistance

7.Test of cure

8.Avoid abuse

2) Antibiotic

How To Make a Proper Choice Of  Antibiotic  For  Lober Pneumonia ?

1. For Emperical Treatment

2. For Definitive Treatment

What Are  The Proper Antibiotics  For  Lober Pneumonia ?

1.Beta-Lactam Antibiotics

i-Penicillins

Classification

I-Natural:

Pen. G:

– Benzyl Pen.G

– Procaine Pen.G

II-Semisynthetic

1.Antistaph

Cloxacillin

Picture2

Picture3

2.Broad S.

Ampicillin

Amoxicillin

3.Extended S.(Anti-pseudomonas)

Carbenicillin

4.Rev.S

Pevmecillinam

What are the contraindications of Penicillins  ?

II- Cephalosporins

Similarities to penicillin:

1.A peptide nucleus (7-amino-cephalosporanoic acid)

2.Inhibition of the transpeptidase of the cell wall.

3.Destroyed by a specific bacterial B-lactamase (cephalosporinase)

Picture4

2.Macrolides (Erythromycin,Azithromycin, Clarithromycin)

•Bind to 50 S ribosomal subunit ( site of chloramphenicol & clindamycin)

•Wide spectrum

•Baceriostatic or bactericidal ( depending on the conc. )

•They accumulate in the macrophages but have no effect on the immune mechanism.

Macrolides   are  wide  spectrum antibiotics ; Mention why ?

Wide spectrum :

= gm.+ve : cocci ( strept., staph., pneumococci)& bacilli ( diphtheria)

= gm- ve : cocci ( Neisseria ) & bacilli (including Helicobacter, H. influenza , Legionella )

=Chlamydia, Mycoplasma, Spirchates and Toxoplasmosis

Adverse effects:

1.G.I upsets, colic

2.Reversible cholestatic hepatitis

3.Allergy

3.Quinolones

How Quinolones act ? How can bacteria resist ? Does it work on human cell ?

Inhibit DNA gyrase

Quinolones spectrum:

Most gm –ve:

  1. E-coli
  2. Proteus
  3. H.influenza
  4. Shigella
  5. Chlamydia
  6. Klebsiella
  7. Pseudomonas
  8. Salmonella
  9. Legionella

Gm +ve :

  1. Strept
  2. Pneum.
  3. staph.

Quinolones Contraindications:

1.Prgnancy & nursing mothers

2.Children under 18 years

3.Epilepsy

What are the causes  of failure of antimicrobial therapy ?

1.Wrong route

2.Impaired defense

3.Poor penetration

4.Wrong culture

5.Pus

6.Foreign body

7.Delay

8.Sub optimal dose

9.Sub optimal duration