(Beta-lactam/penicillin)

Wider anti-bacterial spectrum than benzylpenicillin

Can be inactivated by beta - lactamases

(Beta-lactamase/penicillin)

High efficacy

Low toxicity

Widely-used for penicillin-sensitve infections

Acid labile - given as injection

Can be inactivated by beta-lactamases

BETA LACTAM/PENICILLIN

Acid stable - taken orally

Cannot/shouldn't be used in serious infections because absorption is unpredictable and plasma concentration is variable.

Inhibition of bacterial DNA synthesis/function

metrondiazole

ciprafloxacin

Inhibition of topoisomerase II and IV which are required for bacterial DNA replication, transcription, repair, and recombination

Particularly active against Gram negative bacteria

Many staphylococci are resistant

Impairs drug metabolism

Inhibition of bacterial RNA snythesis

CLARITHROMYCIN

Reversibly binds to the t50 s sub-unit of ribosome or near P donor site so tRNA binding is blocked - subsequent protein synthesis prevented. 

Similar spectrum to penicillin - can be used in penicillin allergic patients!

Increased risk of myopathy in patients using atorvastatin and simvastatin

AMINOGLYCOSIDE (Inhibition of bacterial RNA synthesis)

Irreversibly binds to specific 30s sub-unit proteins and 16s rRNA - leads to interference with initiation complex, misreading of mRNA - incorrect AA's added to the polypeptide = non-functional or toxic peptide

Active against many gram negative bacteria

Almost completely excreted by kidney - dose adjusted according to renal function.

Quinolone (Inhibition of bacterial DNA synthesis/function)

Disrupts DNA helical structure = inhibits nucleic acid synthesis = cell death. 

Active against anaerobic bacteria and protozoa

Used against Clostridium Difficile

CYP450 enzyme inhibitor

Reaction when given with alcohol