Overview of Anti-Microbials

Overview of Anti-microbials and Target Site of Activity

22/8/10

Yung, A. et al (2004) “Infectious Disease: A Clinical Approach” Second Edition, IP Communications Ltd

Anti-microbial = kill or suppress the growth of micro-organisms.

ANTI-BACTERIALS

(i) Inhibition of cell wall synthesis

- Beta-lactams (penicillins, cephalosporins, carbapenems, monobactams)

- Glycopeptides (vancomycin, teicoplanin)

- Others (cycloserine, bacitracin)

(ii) Inhibition of protein synthesis

- Macrolides (ethyromycin, roxithromycin, azithromycin)

- Aminoglycosides (gentamycin, tobramycin)

- Tetracyclines (doxycycline)

- Chloramphenicol

- Clindamycin

- Fusidic acid

(iii) Inhibition of nucleic acid synthesis

- Trimethoprim

- Sulphonamides (sulphamethoxazole)

- Fluoroquinolones (ciprofloxacin, norfloxacin)

- Rifamycins (rifamipicin)

(iv) Inhibitors of cell membrane function

- Colistin

ANTI-VIRALS

- are all virustatic rather than virucidal

- they all suppress virus and allow the host immune system to irradicate disease

- majority = nucleoside analogues -> gain access to the infected cell and then are phosphorylated by viral and/or cellular enzymes.

(1) Drugs for HSV and VZV – inhibition of DNA polymerase

- Acyclovir

- Famciclovir

- Valaciclovir

(2) Drugs for CMV

- Ganciclovir– inhibition of CMV DNA polymerase

- Foscarnet – inihibitor of virion DNA polymerase

- Cidofovir

- Formivirsen – antisense oligonucleotide that inhibits CMV replication

(3) Drugs for HIV

HAART = highly active anti-retroviral therapy

- Nucleoside reverse transcriptase inhibitors (NRTI’s - zidovudine, didanosine, stavudine, lamivudine)

- Nucleotide reverse transcriptase inhibitors (RTI’s - tenofovir)

- Non-nucleoside reverse transcriptase inhibitors (NNRTI’s – nevirapine, efavirenz)

- Protease inhibitors (PI’s - saquinavir, ritonavir, indanvir, nelfinavir, amprenavir, lopinavir)

- Others (enfuvirtide)

(4) Drugs for Influenza

- M2 Channel Inhibitors (amantadine and rimantadine) – disrupts the process of dissociation of matrix and ribonucleoprotein

- Neuraminidase inhibitors (oseltamivir and zanamivir) – impairs release of virus from infected cells

(5) Drugs for other viruses

- Ribavirin – mechanism uncertain

- Alpha-interferon – very complex

- Pleconaril – prevent virus binding and viral uncoating

ANTI-FUNGALS

(i) Interference with ergosterol (sterol in fungal cell membrane)

- Azoles (ketoconazole, fluconazole, itraconazole, voriconazole)

- Allylamines (terbinafine)

(ii) Disruption of fungal cell wall

- Polyenes (amphotericin B, nystatin)

- Echinocandins (caspofungin, micafungin)

ANTI-PARASITICS

Protozoan Parasites

Nitroimidazoles – inhibiting DNA synthesis

- metronidazole

- tinidazole

Other agents:

- Paromomycin

- Nitazoxanide

Metazoan Parasites (nematodes and cestodes = worms)

Benzimidzoles – prevents formation of microtubules and cell division

- albendazole

- mebendazole

Diethylcarbamazine – mechanism unknown

Praziquantel – mechanism unknown

Ivermectin – causes influx of Cl- into cells -> muscular paralysis

Jeremy Fernando (2011)