TB drugs Flashcards
explain the necessity for a multi-drug regimen to treat TB.
TB can, and has become a very drug resistant microbe. therefore, TB must always be treated with two or more drugs to which the organism is sensitive to both kill the bacteria and drop the chances of antibiotic resistance.
what other treatment strategies for TB help decrease resistance and promote cure?
directly observed therapy, that is, taking drug’s in the presence of a healthcare professional (often at a county health clinic) is helpful in decreasing resistance.
using additional antibiotics helps decrease resistance and mitigate side effects, so a four-drug therapy is often used.
finally, doing intermittent dosing, that is dosing every few days instead of everyday helps the patient adhere better.
discuss diagnosis through targeted testing for latent TB.
Tuberculin Skin Test: performed by given a purified protein derivative (PPD), which is an antigen derived form m. tuberculosis. If the individual has an intact immune system and has been exposed to M. Tuberculosis in the past, then the PPD will elicit a local immune response. A positive PPD sign is indicated by a region of induration (hardness) around the injection site.
Interferon Gamma Release Assays: IGRAs are blood tests for TB. WBCs will release interferon gamma when exposed to M. Tuberculosis again. WBCs are isolated from the patient’s blood test and are then exposed to antigens that represent M. Tuberculosis. If the antigens trigger sufficient release of interferon gamma, then the test is considered positive for TB.
explain important diagnostic test for TB including sputum culture, chest X ray, blood testing, and tuberculin skin test.
sputum culture: For the culture, lab staff put some of your sputum into a special container to grow. If bacteria grow, your culture result is positive.
A posterior-anterior chest radiograph is used to detect chest abnormalities. Lesions may appear anywhere in the lungs and may differ in size, shape, density, and cavitation. These abnormalities may suggest TB, but cannot be used to definitively diagnose TB.
blood testing:
Gamma Release Assays: IGRAs are blood tests for TB. WBCs will release interferon gamma when exposed to M. Tuberculosis again. WBCs are isolated from the patient’s blood test and are then exposed to antigens that represent M. Tuberculosis. If the antigens trigger sufficient release of interferon gamma, then the test is considered positive for TB.
Tuberculin Skin Test: performed by given a purified protein derivative (PPD), which is an antigen derived form m. tuberculosis. If the individual has an intact immune system and has been exposed to M. Tuberculosis in the past, then the PPD will elicit a local immune response. A positive PPD sign is indicated by a region of induration (hardness) around the injection site.
consider limitations and interpretation of tuberculin skin testing.
limitations: could just be reaction to antigen from prior exposure, different people can interpret borderline results differently
interpretation: a region of induration (hardness) around the injection site.
Isoniazid
MOA, AEs, interactions, nursing implications–patient teaching
MOA: though data is not certain, it is suggested that the drug suppresses bacterial growth by inhibiting synthesis of mycolic acid, a component of the bacterial cell wall.
AEs:
hepatotoxicity: thought to occur from a toxic isoniazid metabolite. biggest risk factor is advancing age. Patients should be informed about signs of hepatitis, and notify provider if these develop. Patients should be evaluated by a provider monthly for these signs as well. Some clinicians perform AST tests monthly.
interactions:
Isoniazid inhibits CYP2C9, CYP2C19, CYP2E1, all enzymes of cytochrome P450. The inhibition of these enzymes can raise levels of other drugs in the body. These drugs include (Especially) phenytoin, carbamazepine, diazepam, and triazolam. phenytoin monitoring is crucial–if levels too high, pt. will start showing signs of phenytoin excess–ataxia, and incoordination. HOWEVER DO NOT CHANGE DOSAGE OF ISONIAZID TO COMPENSATE.
interactions pt. 2: Alcohol, rifampin, Rifapentine, Rifabutin, pyrazinamide–these drugs and alcohol increase the risk of hepatoxicity.
nursing implications: patient teaching:
take isoniazid on an empty stomach, either 1 hour before meals or 2 hours after meals. Advise patients to take the drug with meals if GI upset occurs.
Inform patients about signs of hepatitis (jaundice, anorexia, malaise, fatigue, nausea) and instruct them to notify the prescriber immediately if these develop.
Urge the patient to limit or minimize alcohol consumption.
inform patients about signs and symptoms of peripheral neuropathy including tingling, numbness, burning, or pain in the hands and feet. Instruct them to notify the prescriber if these occur.
