CHEMOPROPHYLAXIS

Dr Sangeetha P

CHEMOPROPHYLAXIS

Definition The Practice of administering an

antimicrobial agent for preventing an

infection or for suppressing

contacted infection before the clinical

manifestations.

Influencing factors

Host Microbe

Disease Drug

.

Single pathogen

Acute exposure

Short duration prophylaxis

Suitable drug

Lethal disease

Prophylaxis effective when

Ineffective prophylaxis leads to

o Overuse of

antibiotics

o Resistant organisms

o Economic waste

o Risk of side effects

The ideal antibiotic

Narrow spectrum

Cheap

Minimum toxicity

Single dose..

Types of prophylaxis

Causal

•Preventing infection

Clinical

•Preventing clinical manifestations

Classification

Disease targeted

Host targeted

Post exposure

Surgical prophylaxis

Disease targeted prophylaxis

Rheumatic fever Endocarditis Malaria Cholera Plague Influenza

Host targeted

HIV Neutropenia Asplenia Haemoglobinopathy

Post exposure

• Tuberculosis• Pertussis• HIV • Meningococcal meningitis

Surgical prophylaxis• To prevent Surgical Site Infection

(SSI); not all infections occuring in the post-op period..

• Staphylococcus - Cefazolin

Rheumatic fever

Primary Treating streptococcal

pharyngitis

Secondary Preventing a second

episode of pharyngitis

Streptococcal pharyngitis

Oral Penicillin V for 10 days

Oral Erythromycin for 10 days

Inj Benzathine Penicillin 6L IM single dose

Secondary

o Oral Penicillin V 250mg BD daily

o Sulfadiazine 500mg OD

o Erythromycin 250mg BD

Inj.Benzathine Penicillin 1.2L IM 4 weekly

Endocarditis

• High morbidity

• Dental /Surgical procedures with

bleeding from mucosa..

• 2007 AHA guidelines

• Choice of drug depend on the

flora..

Endocarditis

.Upper

GIT

Alpha hemolytic

streptococci

Ampicillin/Amox/clindamycin

Endocarditis .

Lower GIT

ENTEROCOCCI

Ampi+GentaVanco+Gent

a

Ampi/Amox

Antibiotic Regimens for Prophylaxis of Endocarditis in Adults with High-Risk Cardiac Lesions

A. Standard oral regimen• 1. Amoxicillin 2.0 g PO 1 h before procedureB. Inability to take oral medication• 1. Ampicillin 2.0 g IV or IM within 1 h before procedureC. Penicillin allergy• 1. Clarithromycin or azithromycin 500 mg PO 1 h before procedure• 2. Cephalexin 2.0 g PO 1 h before procedure• 3. Clindamycin 600 mg PO 1 h before procedureD. Penicillin allergy, inability to take oral medication• 1. Cefazolin or ceftriaxone 1.0 g IV or IM 30 min before procedure• 2. Clindamycin 600 mg IV or IM 1 h before procedure

Malaria

Tab.Chloroquine 500mg base

once weekly.

Start 2 weeks prior & continue

for 4weeks after travel..

Chloroquine sensitive

Malaria

Atovaquone+Proguanil (Malarone) daily

Mefloquine 250mg weeklyDoxycycline 100mg daily

Chloroquine resistant

Tuberculosis

Treatment of latent infection..

Manteoux +veInfant of

sputum+ve mother

H/O TB,no proper Rx

Regimens • INH 300mg daily for 9 months or• INH +Rifampicin daily for

6months or• Rifampicin for 4 months

• Rifampicin +Pyrazinamide for 2 months.

HIV-Post exposure prophylaxis

Two drug

regime for low risk

Zidovudine +Lamivudi

ne

Zidovudine+Lamivudine+Indin

avir

Three drug regime for high risk

HIV

Prophylaxis against opportunistic infections:

primary

Disease Drug

TB INH

PCP COTRIMOXAZOLE

TOXOPLASMA COTRIMOXAZOLE

MAC AZITHRO/CLARITHRO

VARICELLA ACYCLOVIR

Secondary or c/c suppressive Rx

.Disease Drug

PCP Co-trimoxazole

Toxoplasma Co-trimoxazole

MAC Azithromycin

CMV Gancyclovir/foscarnet/cidofovir

Cryptococcosis Fluconazole

Salmonella bacteremia

Ciprofloxacin

OTHERS

Disease Drug

Meningococcal meningitis

Ceftriaxone/Rifampicin /Ciprofloxacin

Pertussis Erythromycin

Cholera Tetracycline

Plague Doxycycline

Syphilis Ceftriaxone

Recurrent UTI Cotrimoxazole

Recurrent genital herpes

Acyclovir

Surgical prophylaxis

To prevent Surgical

Site Infection

(SSI)

Maintain peak

concentration of

antibiotic at time of

wound closure

Surgical prophylaxis

Principles Give antibiotics 1 hour before surgeryContinue for 24 hours onlyMost commonly cephalosporins

Types of surgical wounds

.

Clean Clean

Contaminated

Contaminated

Dirty

•

Type Example

Clean Elective, no viscera or tract entered.

Neurosurgery

Clean contaminated

Opening of viscera with minimal spillage

GI Surgery

Contaminated

Gross spillage.Non purulent inflammation

Gut resection

Dirty Purulent Opening of an abscess

Drugs usedSurgery Organism Antibiotic

Clean Staphylococcus

Cefazolin

Clean contaminatedHead&neck

Oral anaerobes

Cefazolin+Clindamycin

Clean contaminated colorectal

Anaerobes Neomycin,Cefoxitin

Dirty Anaerobes ,Gram negative aerobes

Cefoxitin,Gentamycin

High risk when

• Surgery >2hours• Prosthesis• Immunosuppressed patient• Extremes of age..