Q: How is Isoniazid used therapeutically?
A: Primary drug in all regimens, also prophylaxis.

Q: How is Rifampin used therapeutically?
A: Excellent tuberculicidal drug, most rapid acting. Also useful for other bacterial infections.

Q: How is Ethambutol used therapeutically?
A: Very effective with Isoniazid.

Q: How are Pyrazinamide and Streptomycin used therapeutically?
A: Used when organism is resistant to Isoniazid, Rifampicin, and Ethambutol.

Q: What are some of the difficulties with tuberculosis therapy?
A: Immunosuppressed patients, long therapy (6-24 months), organism grows slowly, rapid development of resistance, and all useful drugs possess toxicity problems.

Q: What is the mechanism of action of Isonizid?
A: Inhibit synthesis of mycolic acid and DNA synthesis.

Q: Is Isoniazid bacteriostatic or bacteriocidal?
A: Static is bacilli are resting, cidal if bacilli are growing.

Q: What are the toxicities associated with Isoniazid?
A: Peripheral neuritis, hepatitis, and hypersensitivity reactions.

Q: What is the mechanism of action of Rifampin?
A: inhibits RNA polymerase.

Q: What are the toxicities associated with Rifampin?
A: Jaundice, tears and urine turn red-orange, induces hepatic metabolism of other drugs, GI distress, diarrhea.

Q: What is the mechanism of action of Ethambutol?
A: Tuberculostatic, so never used alone. 

Q: What are the toxicities associated with Ethambutol?
A: Decreased visual acuity, impaired ability to perceive green, and may precipitate gout. 

Q: What is the mechanism of action of Streptomycin?
A: Aminoglycoside (same limited distribution and toxicities), must be administered parenterally.

Q: What are the toxicities associated with Streptomycin?
A: Ototoxicity, vestibular toxicity, and nephrotoxicity.

Q: What is the mechanism of action of Pyrazinamide?
A: Bactericidal

Q: When is Pyrazinamide used?
A: When resistance problems require a third drug.

Q: What are the toxicities associated with Pyrazinamide?
A: Liver necrosis, hyperuricemia, nausea, and vomitting.