Macrolide

The macrolides are a group of  drugs (typically antibiotics) whose activity stems from the presence of a macrolide ring, a large  lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, are attached. The lactone ring can be either 14, 15 or 16-membered. Macrolides belong to the polyketide class of natural products.

The most commonly-prescribed macrolide antibiotics are:  

Erythromycin,  Clarithromycin, Azithromycin, roxithromycin,

Others are: spiramycin (used for treating  toxoplasmosis), ansamycin, oleandomycin, carbomycin and tylocine.

There is also a new class of antibiotics called ketolides that is structurally related to the macrolides. Ketolides such as telithromycin are used to fight respiratory tract infections caused by macrolide-resistant bacteria.

Non-antibiotic macrolides :The drug Tacrolimus, which is used as an

immunosuppressant, is also a macrolide. It has similar activity to  cyclosporine.

Uses : respiratory tract infections and soft tissue infections.

Beta-hemolytic  streptococci,  pneumococci, staphylococci and enterococci are usually susceptible to macrolides. Unlike penicillin, macrolides have shown effective against mycoplasma, mycobacteria, some rickettsia and chlamydia.

Mechanism of action: Inhibition of bacterial protein synthesis by binding reversibly to the subunit 50S of the bacterial ribosome, thereby inhibiting translocation of peptidyl-tRNA. This action is mainly bacteriostatic, but can also be bactericidal in high concentrations

Resistance : Bacterial resistance to macrolides occurs by alteration of the structure of the bacterial ribosome.

Clotrimazole: Clotrimazole is a potent, specific inhibitor of p450 enzymes.

It is used in some antifungal medications, and in the treatment of yeast infections.

Ketoconazole

synthetic antifungal drug

used for infections such as  athlete's foot, ringworm, candidiasis (yeast infection or thrush), jock itch.

Ketoconazole is used to treat eumycetoma, the fungal form of mycetoma.

MOA: Ketoconazole is imidazole structured, and interferes with the fungal synthesis of  ergosterol, the main constituent of cell membranes, as well as certain enzymes. It is specific for fungi, as mammalian cell membranes contain no ergosterol.

Sensitive fungi Ketoconazole inhibits growth of  dermatophytes and  yeast species (such as Candida albicans).

Cephalosporins

Produced semisynthetically by chemical attachment of side chains to 7-aminocephalosporanic acid. Same mode of action , same resistance mech. 
But tend to be more resistant than penicillins to certain beta –lactamases .

GENERATION BASED ON :
-- BACTERIAL SUSCEPTIBILITY PATTERNS
-- RESISTANCE TO BETA –LACTAMASES
--NOT EFFECTIVE AGAINST -MRSA , L. MONOCYTOGENES , C. DIFFICLE , ENTEROCOCCI

First Generation 

Parentral

- CEPHALOTHIN
- CEFAZOLIN

Oral

- CEPHALEXIN
- CEPHRADINE
- CEFADROXIL

Second Generation

Parentral

CEFUROXIME
CEFOXITIN

Oral

CEFACLOR
CEFUROXIME AXETIL

Third Generation

Parentral

CEFOTAXIME 
CEFTIZOXIME
CEFTRIAXONE 
CEFTAZIDIME
CEFOPERAZONE

Oral 

CEFIXIME 
CEFPODOXIME
CEFDINIR 
CEFTIBUTEN

Fourth Generation

Parentral

CEFEPIME
CEFPIROME

Methods of general anesthesia

CIRCLE SYSTEM

*HIGH-FLOW

FRESH GAS FLOW > 3 l/min.

*LOW-FLOW

FGF ok. 1l/min.

*MINIMAL-FLOW

FGF ok. 0,5 l/min.

Nalidixic acid:

Nalidixic acid is the basis for quinolone antibiotics. It acts bacteriostatically (that is, it inhibits growth and reproduction) or bactericidally (it kills them) on both Gram positive and Gram negative bacteria, depending on the concentration. It is especially used in treating urinary tract infections, caused for example by Escherichia coli, Proteus, Enterobacter and Klebsiella.