Classification of antibacterial drugs

Antibacterial drugs or antibiotic drugs are commonly use medicine for all kind of infections, hence we have to know about this drugs more clearer.

According to side of action, antibiotic divided into 3 main groups:

1. Inhibition of cell wall synthesis:

Beta-lactams, the structure of which contains a beta-lactam ring. The major subdivisions are:

• penicillins whose official names usually include or end in 'cillin'.
• cephalosporins and cephamycins which are recognised by the inclusion of 'cef' or 'ceph' in their official names.

Lesser categories of beta-lactams include:

• carbapenems (e.g. meropenem...)
• monobactams (e.g. aztreonam...)
• beta-lactamse inhibitors (e.g. clavulanic acid...)

Other inhibitors of cell wall synthesis include vancomycine and teicoplanin.

2. Inhibition of protein synthesis:

Aminiglycoside. The names of those that are derived from streptomyces end in 'mycin', e.g. tobramycin. Other include gentamicin and semisynthesis drugs, e.g.amikacin.

Tetracyclines as the name suggests are four-ringed structures and their names end in '-cycline'

Macrolides, e.g.erythromycin. Clindamicin, structurally a lincosamide, has a similar action and overlapping antibacterial activity.

Other drugs that act by inhibiting protein synthesis include quinapristin-dalfopristin, linezolid, chloraphenicol and sodium fursidate.

3. Inhibition of nucleic acid synthesis:

Sulphonamides, usually their names contain 'sulpha' or 'sulfa'. These drugs, and trimethophrim, with which they may be combined, inhibit synthesis of nucleic acid precursors.

Quinolones, are structurally related to nalidixic acid; the names of the most recently introduced members of the group end in '-oxacin', e.g. ciprofloxacin. They act by preventing DNA replication.

Azoles, all contain an azole ring and the names end in '-azole', e.g. metronidazole. They act by the prodcution of short-lived intermediat compounds which are toxic to DNA of sensitive organisms. Rifapicin inhibits bacterial DNA-dependent RNA polymerase.

[To be continued... ]

Source: Clinical Pharmacology, 9th edition, P.N.Bennett and M.J.Brown, 2003