Rifalazil (also known as KRM-1648 and AMI-1648) is an

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

substance that kills bacterial cells by blocking off the β-subunit in

RNA polymerase In molecular biology, RNA polymerase (abbreviated RNAP or RNApol), or more specifically DNA-directed/dependent RNA polymerase (DdRP), is an enzyme that synthesizes RNA from a DNA template. Using the enzyme helicase, RNAP locally opens the ...

. Rifalazil is used as treatments for many different diseases. Of the most common are ''Chlamydia'' infection, ''Clostridium difficile'' associated diarrhea (CDAD), and

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

(TB). Using rifalazil and the effects that coincide with taking rifalazil for treating a bacterial disease vary from person to person, as does any drug put into the human body. Food interactions and genetic variation are a few causes for the variation in side effects from the use of rifalazil. Its development was terminated in 2013 due to severe side effects.

Biological properties

Rifalazil works well alone, and in conjunction with other antibiotics alone. In a study conducted in 2005, it was found that combining rifalazil with

vancomycin Vancomycin is a glycopeptide antibiotic medication used to treat a number of bacterial infections. It is recommended intravenously as a treatment for complicated skin infections, bloodstream infections, endocarditis, bone and joint infections, ...

increased bacterial killing by a factor of 3. Rifalazil also has a very long half-life which allows more infrequent dosages as opposed to frequent small dosages of antibiotics. Many different studies have been conducted that researched the effect of rifalazil on certain strains of bacterial diseases. In a study conducted in 2004, it was found that rifalazil reduces ''C. difficile'' strains when studied ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...

''.

Uses

Rifalazil has been developed to treat cases of

and

chlamydia Chlamydia, or more specifically a chlamydia infection, is a sexually transmitted infection caused by the bacterium ''Chlamydia trachomatis''. Most people who are infected have no symptoms. When symptoms do appear they may occur only several wee ...

. It is very good treatment for tuberculosis because rifalazil achieves very high concentration in the blood cells and the lungs. In addition, rifalazil is becoming more widely used because it can be used along with many other indications, such as

HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...

, TB, and

MRSA Methicillin-resistant ''Staphylococcus aureus'' (MRSA) is a group of Gram-positive bacteria that are genetically distinct from other strains of ''Staphylococcus aureus''. MRSA is responsible for several difficult-to-treat infections in humans. ...

. Rifalazil has a very long

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ato ...

which is very useful for certain medications. The drug is administered orally which is also convenient in terms of drug administration. A longer half-life allows for few treatments and dosage which makes this an up-and-coming drug for tuberculosis, CDAD, and chlamydia. Although the uses for rifalazil seem very effective, there are negative side effects which make the use limited. Rifalazil interacts with other drugs and on top of that, rapid resistance develops to other drugs.

Tested diseases for rifalazil treatment

* ''Chlamydia'' infection * ''Clostridium difficile'' associated diarrhea *

Trachoma Trachoma is an infectious disease caused by bacterium ''Chlamydia trachomatis''. The infection causes a roughening of the inner surface of the eyelids. This roughening can lead to pain in the eyes, breakdown of the outer surface or cornea of ...

Tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

Leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...

Buruli ulcer Buruli ulcer () is an infectious disease characterized by the development of painless open wounds. The disease is limited to certain areas of the world, most cases occurring in Sub-Saharan Africa and Australia. The first sign of infection is a s ...

References

{{Authority control Abandoned drugs Phenylpiperazines Rifamycin antibiotics Anti-tuberculosis drugs Heterocyclic compounds with 4 rings