Tuberculosis Flashcards
(11 cards)
What is pharmacological treatment involved in TB?
Rifampicin – inhibits RNA synthesis
Isoniazid – inhibits mycobacterial cell wall synthesis (inhibits synthesis of mycolic acid)
Pyrazinamide – interferes with cell membrane transport, cell wall and fatty acid synthesis
Ethambutol – inhibits cell wall synthesis (inhibition of arabinogalactan)
What is the treatment algorithm?
First 2 months; 3-4 drugs used. (Rifabutin should be used in HIV patients to avoid drug interactions)
Next 3-6 months; isoniazid and rifampicin continued
What are some side effects of rifampicin? (quite non-specific)
Nausea, vomiting, rash, fever, diarrhoea
What are some side effects of isoniazid? (quite non-specific)
Nausea, vomiting, allergic skin reactions and peripheral neuropathy
What are some side effects of pyrazinamide?
Gout, GIT discomfort, drug - induced hepatitis at higher doses
What are some side effects of ethambutol?
Renal and hepatic damage, rarely optic and peripheral neuropathy
What is the name of the B6 supplement agent given with isoniazid?
Pyridoxine
Mechanism: given to prevent peripheral neuropathy with isoniazid.
What is mechanism of action for isoniazid?
It is prodrug, that must be activated by enzyme in mycobacterium tuberculosis called KatG. It inhibits mycolic acid synthesis, which are important for mycobacterial cell wall.
What is the mechanism of action of pyrazinamide?
It is prodrug activated by pyrazinoic acid, and inhibits fatty acid synthase.
Pyrazinamide can cause flares of gout as result of decreased renal excretion of uric acid. It is also the most common cause of drug-induced hepatitis.
What is the mechanism of action of ethambutol?
It works by obstructing formation of cell wall. It prevents arbinogalactan synthesis, and as it is an important part of cell membrane formation, it increases permeability of the cell wall.
What is the mechanism of action of rifampicin?
Inhibits bacterial RNA synthesis by inhibiting RNA polymerase.
