
There are many classes of antibiotics. It is useful to know at least a handful of antibiotics, and what they are useful for. Below we attempt to summarise the main types of antibiotics, their mechanisms and their common uses.
Antibiotic Classification and Mechanisms – Click for full size
Gram Positive and Gram Negative Bacteria – Click for full size
Rifamycins Inhibits DNA transcription | Rifamycin, rifabutin | Cidal | Nausea, anorexia, pseudomembranous colitis, hepatotoxicity, orange colouration of excreted bodily fluids, toxicity syndromes, drug interactions | Also used in mycobacterial infections – these most commonly occur in those with HIV. Resistance prevents more widespread use | Widespread – develops rapidly | Y | ? | ? | ? |
Isoniazid Inhibits synthesis of cell wall | Isoniazid | Cidal / static | Nausea, vomiting, constipation, peripheral neuropathy, hepatitis, SLE-like-symptoms | Bactericidal on dividing organisms, static on resting. Only effective against myobacteria | Occurs rapidly if used alone | N | N | N | ? |
Pyrazinamide Lowers intracellular pH, disrupting synthesis of fatty acids | pyrazinamide | Cidal | Hepatotoxicity, nausea, vomiting, arthralgia, sideroblastic anaemia | Only effective against myobacteria | Occurs rapidly if used alone | N | N | N | ? |
Ethambutol Interferes with cell wall synthesis | Ethambutol | Static | Optic neuritis – resulting in red/green colourblindness. neuritis | Only effective against myobacteria | Uncommon | N | N | N |