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33 Cards in this Set
- Front
- Back
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What are the first-line anti-TB drugs?
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RIPE: Rifampin, isoniazid, pyrazinamide, ethambutol
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Which is bacteriostatic?
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Ethambutol
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How do mycobacteria develop isoniazid resistance?
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Delete katG gene for catalase, isoniazid requires this for activation, it inhibits enzymes for mycolic acid synthesis for the cell wall
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What are the adverse events of isoniazid?
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Hepatotoxicity (metabolized by the liver), Vit B deficiency leads to peripheral neuropathies
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What do you take to prevent the neuropathies?
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Pyridoxin (icy cat is a paradox)
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What happens when isoniazid is given with phenytoin?
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Phenytoin metabolism is inhibited, so the pt develops ataxia
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Who are rapid acetylators of isoniazid? Slow?
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Rapid - chinese, isoniazid gets metabolized quickly; slow - israeli
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What is rifampin's mode of action?
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It blocks the bacterial RNA polymerase by binding to it's beta-subunit and inhibits RNA synthesis. (blocks transcription)
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What adverse events does rifampin cause?
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Abdominal discomfort and fever, skin eruptions and hepatitis, red urine (warn for leprosy). IMP: increases elimination of other drugs (OCPs, steroids) (rifampin--rival)
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What should you give instead of rifampin for AIDS patients?
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Rifabutin, does not increase metab of PI's.
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What is pyrazinamide's mode of action?
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It must be converted to pyrazinoic acid by bacterial enzyme pyrazinamidase. It is active at pH 5.5, good for intracellular bacilli in lysosomes. (pyramid accumulation in lysosomes)
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What are the adverse events of pryazinamide?
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Hepatitis, hyperuricemia and gout, arthralgia, fever and skin rashes.
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What do you want to monitor for pyrazinamide?
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SGOT levels - serum glucose oxaloacetic transmaminase levels for liver. (SPOT the SGOT)
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What is ethambutol's mode of action?
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It inhibits arabinosyl transferase in bacterial cell wall synthesis.
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What can ethambutol be used for?
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TB meningitis - can go to CNS.
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What are the adverse events of ethambutol?
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Retrobulbar neuritis resulting in loss of visual acuity and red-green blindness (optic neuritis) -- e for eyes. Also, peripheral neuritis, HA, skin rash. Do monthly tests for visual acuity.
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What is the mode of action for streptomycin?
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It inhibits baceterial protein synthesis by binding to 30S on the bacterial ribosome.
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What is different about the mode of administration for streptomycin?
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It is given IV or IM (versus oral) and has low intracellular concentrations. It is excreted unchanged.
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What are the adverse events for streptomycin?
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Ototoxicity (vestibular and auditory), renal injury, hypersensitivity. strepto--OOO my EARR AND BALANCE!!! Do routine audiometry to check.
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What are the second-line anti-TB drugs?
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PECC = Paramino salicylic acid, Ethionamide, Clofazimine, Cycloserine and Fluoroquinolines
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What is the mode of action for paramino salicylic acid?
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It competes with PABA for mycobacterial dihydropteroate synthetase for folate biosynthesis. It is bacterioSTATIC.
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What is paramino salicylic acid given with?
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FOOD bc causes GI problems.
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What are the adverse events of PAS?
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GI problems, hepatitis, hypersensitivity (give with food and antacids)
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What is the mode of action for ethionamide?
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Like IsONiAzid (ethIONAmide) - block synthesis of mycolic acids (cell wall).
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What are the adverse events for ethionamide?
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GI, hepatotoxicity, neurologic problems (give pyridoxine again)
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What is the mode of action for clofazimine?
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It inhibits bacterial DNA synthesis. This is also used for leprosy.
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What is unique about clofazimine?
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Concentrates in reticuloendothelial system, slowly released from these deposits. Causes red-brown color bc accumulates in tissue, pts do not like. (look like a diseased CLOwn), Causes discoloration of skin, urine and feces
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What is the method of action by cycloserine?
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It acts by inhibiting cell wall synthesis. It is rarely used due to poor efficacy and adverse effects.
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What is the mode of action of fluoroquinolones?
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They act by inhibiting topoisomerase II. Include ciprofloxacin, moxifloxacin, levofloxican. Moxifloxican is useful for drug resistant TB. Used for atypical mycobacterium infections.
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What do you give to treat leprosy?
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Combination tx of Rifampin, Clofazamine and Dapsone for MB and Rifampin and Dapsone for PB leprosy.
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What is dapsone's mode of action?
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It inhibits folate synthesis.
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What is dapsone's metabolism?
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It is excreted into bile and reabsorbed from the intestine, then excreted in the urine.
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What are the adverse side effects of dapsone?
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The drug is well tolerated. It causes fever, GI, skin rash, exfoliative dermatitis. It should not be given to pts with sulpha drug allergies.
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