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30 Cards in this Set
- Front
- Back
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What are the first line drugs in the treatment of TB?
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STRIPE!!!
Streptomycin Rifampin Isoniazid Pyrazinamde Ethambutol |
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What is the preferred treatment for latent TB infection?
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Isoniazid
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Name the drug to use as an alternative to treat latent TB infection
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Rifampin
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Explain why combined drug therapy for a prolonged period is necessary for effective treatment of TB
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At least 2 drugs must be used to prevent the emergence of new resistance
A resistant mutant can be redily selected out by using one drug therapy |
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Whys is the emergence of drug resistance a problem for anti- TB therapy?
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Emergence of drug resistance is a problem because TB tends to grow very slowly and there is potentially a resistant mutant for every drug that can be used.
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Why is there no apparent cross resistance between 1st line anti- TB drugs?
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Each of the ist line drug targets a different aspect of TB
The probability of an organism having mutations that render it resistant to all 4 mechanisms of action is highly unlike if all 4 drugs used at the same time. Therefore there is no cross resistance |
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What is the MOA for Ethambutol?
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Provides coverage for RIF and INH resistance
BACTERIOSTATIC Inhibition of cell wall sythesis (inhibits arabinosyl transferase) |
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What is the MOA for Rifampin?
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Inhibition of transcription
Inhibits bacterial DNA dependant RNA polymerase (bind to beta subunit to prevent DNA binding) |
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What is the MOA for Isoniazid?
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Inhibition of cell wall synthesis- affects mycolic acid synthesis in the cell wall
BACTERIOCIDAL Prodrug (need to be activated) |
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What is the MOA for Pyrazinamide?
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Inhibition of translation (protein sythesis
BACTERIOCIDAL Binds to ribosomal protein S1 |
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Which drug has selective toxicity when it comes to its MOA?
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Rifampin
Toxic to bacterial enzymes but does not bind as well to human enzymes |
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Which of the 1st line agents are bacteriocidal?
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RIP
RIfampin Isoniazid Pyrazinamide |
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Which of the fist line agents are hepatotoxic?
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RIP
RIfampin Isoniazid Pyrazinamide |
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Which of the agents mentioned was not orally effective?
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Streptomycin
must be administered parentally |
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Which of the 1st line agents is bacteriostatic and non-hepatotoxic?
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Ethambutol
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What are some of the adverse effects of Isoniazide?
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inhibits CYP450 enzymes mainly 3A4
Inhibits neurons and hepatocytes (INH) peripheral neuropathy and CNS toxicity Decrease Vitamin B6 (must be dosed with it)- decreases neurotransmitter synthesis Neuropathy in slowsacetylators, malnourished, alcholics ot diabetics |
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What are some of the adverse effects of Rifampin?
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POTENT CYP450 INDUCER
rash, fever, NVD, abdominal pain hepatitis rare! Flu like syndrome May turn bodily excretions red! (urine, saliva, tears, sweat) |
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What are some of the adverse effects of Pyrazinamide?
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MOST HEPATOTOXIC of the 1st line agents
Hyperurecemia (inhibits uric acid secretion) |
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What are some of the adverse effect of Ethambutol?
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Optic neuritis
Hyperurecemia |
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What are some of the adverse side effects of Streptomycin?
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PERMANENT ototoxicity and nephrotoxicity
(mostly dose related) |
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Which drugs can precipitate an attack of gout?
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Pyrazinamide and Ethambutol
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Which drug is most likely to cause occular toxicity?
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Ethambutol
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Age is an important risk factor for drug induced hepatotoxicity with which drug?
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Isoniazid
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Name which of the RIPE combination has significan interactions with protease inhibitors and NNRTIs. What is the mechanism of this reaction?
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Rifampin
potent inducer of CYP 450 enzymes so it allows for NNRTIs and proteases to be metabolized faster so that their levels are reduced (drugs are less effective) |
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Which agent is substituted to avoid potential interactions with RIPE combo and HIV therapy agents?
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Rifabutin substituted for RIfampin
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Why is Ethambutol included in the 1st line treatment of TB if it is the least effective of all the agents?
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included incase TB is resistant to INH and RFP
if suceptibility proven then Ethambutol is dropped from therapy |
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How is Streptomycin currently used in the treatment of TB?
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Only used for more serious possible life threatening TB cases that have increased drug resistance
bacteriocidal and given parentally |
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What is the recommended intial and continuation therapy for treatment of active TB in the general pop? (NO INH RESISTANCE)
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Treatment for 6 month
2 month- all 4 drugs; ETB may be dropped if TB not resistant. PZA must be on board for 2 months INH and RIF are continued for the remainder of the 4 month |
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What is the recommended intial and continuation therapy for treatment of active TB in the general pop? ( INH RESISTANCE)
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RIF + PZA + ETB for 6 month therapy
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What is the recommended intial and continuation therapy for treatment of active TB in the general pop? (RIF RESISTANCE)
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INH + PZA + ETB + FQ for 2 months
Remove PZA and then continue the rest of the agents for another 10-16 months |
