Tuberculosis Flashcards
What is the causitive pathogen of tuberculosis?
mybacterium tubercolsis
How is tuberculosis transmitted?
actively infected patients WITH symptoms, not patients that have latent disease spread disease through aerosolized droplet nuclei
Who is at risk for tuberculosis infection?
CLOSE CONTACT
- family members/household contact
- co-workers
- healthcare personnel
- nursing home residents
- persons experiencing homelessness
- persons who are incarcerated
What are the risk factors for active TB disease?
- HIV/AIDS
- immune system dysfunction
- incarceration
- homeless
- alcoholism
- malnutrition
- IV drug use
- renal failure
What are the clinical manifestations of active TB?
- fatigue
- fever and chills
- anorexia
- hemoptysis (vomiting blood)
- weight loss
- night sweats
- cough
What type of isolation is required for patients with active TB?
negative air flow isolation
What drugs are drug resistant TB organisms resistent to?
isoniazid or rifampin
How is drug resistant TB developed?
- primary= transmission of drug-resistant organisms
- secondary= development of resistance due to inadequate treatment, non-adhearance, or variation in pharmacokinetic parameters
What are the risk factors for drug resistant TB?
- exposure to person with known drug-resistant TB
- exposure to person who experienced treatment failure or relapse
- exposure to person born in a region with high resistace rates
- exposure to persons who continue to have positive smears after 2 months of therapy
- travel to areas with high resistance
- non-adhearance to treatment
What are the principles of tuberculosis drug therapy?
- rapid detection of patient with active TB disease
- isolation of patients with active TB disease
- collect appropiate clinical specimens for diagnosis
- prompt initiation combination therapy
- directly observed therapy (DOT) utilization
- prompt reporting of TB diagnosis to appropiate public health organization
What are the first line agents for tuberculosis treatment?
- isoniazid
- rifampin
- pyrazinamide
- ethambutol
How is isoniazid dosed?
weight based dosing using total body weight
What are the dosage forms of Isoniazid?
PO, IM
What is the bioavaliability of Isoniazid?
well absorbed, 100% bioavaliability
How is Isoniazid distributed?
widely distributed into fluids and intracellular spaces
How is Isoniazid metabolized?
primarily metabolized by NAT2 which is genetically polymorphic
What are the adverse effects of Isoniazid?
- increased transaminases
- hepatitis
- peripheral neuropathy
- neurotoxicity
- anemias
- cytopenias
What can be given to patients at risk for peripherl neuropathy associated with Isoniazid use?
pyridoxine (B6)
What are the drug interactions with Isoniazid?
- antacids
- phenytoin
- carbamazepine
- valproic acid
- benzodiazepines
- disulfiram
- warfarin
- acetaminophen
What is consider the most important drug for TB?
rifampin
BUT cannot be used alone
What are the adverse effects of Rifampin?
- GI reactions
- hepatotoxicity
- flu-like symptoms
- orange like discoloration of bodily fluids
- blood dycrasias
What are the drug interactions of Rifampin?
INDUCES CYP450 ENZYMES
- clarithromycin, erthromycin
- azole antifungals
- estrogens
- protease inhibitors (HIV drugs)
- beta blockers
- warfarin
- calcium channel blockers
- digoxin
- immunosuppressants
What are the dosage forms of Rifampin?
IV, PO
What are the dosage forms of Pyrazinamide?
PO
What is unique about the MOA of Pyrazinamide?
prodrug that is activated by pyrazinamidase enzyme of susceptible M. tuberculosis
What is the dosing of Pyrazinamide?
weight based dosing using lean body weight
How is Pyrazinamide excreted?
urine via glomerular filtration
What are the adverse effects of Pyrazinamide?
- GI upset
- arthralgia
- hyperuricemia
- gout
- hepatotoxicity (issue when in combo with rifampin)
What are the drug interactions of Pyrazinaminde?
rifampin, not typically used together but if they must- only for a short time due to hepatotoxicity
What are the dosage forms of Ethambutol?
PO
How is Ethambutol dosed?
weight based dosing using lean body weight
What are the adverse effects of Ethambutol?
- optic neuritis
- decreased visual acuity/blurry vision or decrease color discrimination
- hypersensitivity reactions
- hyperuricemia and gout
- thrombocytopenia
What are the drug interactions of Ethambutol?
no significant drug interactions
What are the second line/alternative agents for tuberculosis?
- rifabutin or rifapentine
- moxifloxacin or levofloxacin
- bedaquiline
- linezolid
- cyclosporin
- amikacin or streptomycin
- ethionamide
What drugs are included in the intensive phase?
- rifampin
- isoniazid
- pyrazinamide
- ethambutol
How long does the intensive phase last?
2 months
What is the preferred dosing for the intensive phase?
once daily
How long is the continuation phase?
4 months or 7 months
What drugs are used in the continuation phase?
isoniazid and rifampin
When would 7 months be considered for the continuation phase?
PATIENTS W/ CAVITATION ON INITIAL CXR AND WHO HAVE A POSITIVE SPUTUM CULTURE AFTER 2 MONTHS ON INTENSIVE THERAPY, but may also consider for:
- cavitation OR positive cultures after intensive phase
- patients who intensive phase did not include pyrazinamide
- persons with HIV not recieving antiretroviral therapy during TB treatment
- extensive disease on CXR
- active smoker
What is the recommended monitoring during TB treatment?
- sputum smears and cultures
- drug and susceptibility testing
- chest xray
- weight
- symptom and adhearance review
- vision assessment
- AST, ALT, billirubin, alkaline phosphate
- platelet count
- creatine
- HIV
- hep B & C
- diabetes status
What is the new 4-drug, 4-month regimen?
- rifapentine
- moxifloxacin
- isoniazid
- pyrazinamide
What are the preferred regimens for treatment of latent TB?
- isoniazid + rifapentine once weekly for 3 months
- rifampin daily for 4 months (not typically used alone)
- isoniazid + rifampin daily for 3 months
