5 (Student Presentation) - Anti tuberculosis: Rifampicin

Question 1

Rifampicin type of action

Answer 1

Bactericidal for both gram (+) and gram (-) intracellular and extracellular microorganisms

Question 2

MoA of Rifampicin

Answer 2

Rifampicin (RIF) binds to the β subunit of DNA-dependent RNA polymerase (RNAP) of M. tuberculosis → Stable drug–enzyme complex → Suppression of chain formation initiation in RNA synthesis → Cell death

Question 3

PK of Rifampicin

Answer 3

Absorption: Well & rapid absorption in the GI tract, especially when administered on an empty stomach

Distribution: 80% transported via blood plasma, well distributed in body tissues (esp in lung & stomach wall)

Metabolism: Primarily hepatic, undergoes deacetylation into deacetylrifampicin

Excretion: 30% urine, 60-65% feces

Question 4

Common side effects of Rifampicin

Answer 4

GIT disturbances (loss of appetite, vomitting, nausea), fever syndrome, flushing on face/neck, itching, and rashes

Question 5

Side effect management

Answer 5

GIT problems –> Give rifampicin during or immediately after a meal

Flushing on face/neck, itching, rashes –> Occasional desentization

Fever syndrome –> Reduce dose size of rifampicin. If this is unsuccessful change to daily administration.