| Structure/Class |
|
| Pharmacodynamics |
- Rifampicin functions by binding to RNA polymerase, therefore inhibiting RNA synthesis.
- Its spectrum of activity covers Gram+ve cocci, Gram-ve cocci, enteric bacteria, chlamydia and mycobacteria (for which it is bactericidal)
- Importantly, rifampicin mutations are widespread, and rifampicin should therefore not be used as single therapy but rather, as combination therapy.
- Indications therefore as follows:
- Mycobacterium infections (in combination with isoniazid)
- To eliminate the carrier status of meningococci
- Can be used to treat serious staph infections (e.g. valve disease or osteomyelitis)
|
| Absorption/administration |
- PO, well absorbed
|
| Distribution |
- Highly protein bound drug.
- Limited penetration to the CSF unless the meninges are already inflamed.
|
| Metabolism |
- Hepatic, but no need for dose adjustment in liver or renal disease.
|
| Excretion |
- Mostly in faeces, small amount in urine.
|
| Interactions |
- Remember that rifampicin is a strong inducer of hepatic CYP450 enzymes. Therefore, it increases the excretion of methadone, warfarin, etc.
|
| Adverse events |
- Orange coloured bodily fluids.
- Cholestatic jaundice and occasional hepatitis.
|
| Dosing/administration |
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| Toxicology |
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| Withdrawal syndrome |
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| Special notes |
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