The treatments for active mycobacterium tuberculosis, referred to as M. TB, consist of four drug therapy regimens given over six to nine months. The Centers for Disease Control and Prevention reports the Food and Drug Administration has approved 10 medications for TB treatment. Based on effectiveness, drug choices decrease due to the existence of multi-drug resistant TB. The first-line TB agents are isoniazid, rifampin, ethambutol and pyrazinamide. These drugs cause adverse side effects, and patients taking these medications receive additional drugs to relieve symptoms.
Isoniazid
The antibiotic izoniazid, or INH, has a very specific and effective action against M. TB. INH interferes with the TB bacteria's production of proteins, fats and nucleic acid, which are vital for reproduction. Physicians prescribe patient dosages of isoniazid based on patient weight. Typically patients take INH 3 times a day on an empty stomach. Unfortunately, according to "Pearson Nurse's Drug Guide 2010," INH causes indigestion, nausea and vomiting. Other common side effects include fever, chills, and fatigue. INH also interferes with the absorption of vitamin B6. Low blood levels of vitamin B6 causes numbness and tingling in the hands and feet, which is referred to as neuropathy. Physicians commonly prescribe Vitamin B6 supplements to prevent neuropathy. INH frequently causes hepatitis or inflammation of the liver. Hepatitis causes right sided abdominal pain and elevated liver enzymes. Patients require routine lab work to monitor for this complication and should report these side effects to a doctor.
Rifampin
Rifampin, or RIF, is taken once a day with INH and has similar effects to INH. RIF prevents the TB bacteria from replicating just like INH does, but it also kills TB cells. In her article in the November 2007 "American Nurse Today," Rebecca Rupert warns health care providers to educate patients to expect orange urine. RIF also stains contact lenses orange. Because INH and RIF create a high risk for hepatitis, patients should observe for and report the incidence of right upper-quadrant abdominal pain, muscle pain, nausea and vomiting, yellow discoloration of the skin and eyes and dark colored urine.
Ethambutol
Physicians give ethambutol with other anti-tuberculin drugs because EMB delays the development of drug resistance. Ethambutol is taken once a day and must be protected from light to prevent degradation of the drug. Patients who experience retrobulbar optic neuritis, a common adverse effect, need to stop taking the drug to prevent permanent eye damage. Patients should report visual disturbances, color blindness and eye pain immediately. Symptoms typically resolve a few months after stopping EMB.
Pyrazinamide
Taken four times a day and always used in conjunction with other TB medications, pyrazinamide (PZA) improves the effectiveness of INH and other TB drugs. PZA can cause rare but fatal hemoptysis, which involves coughing up blood from the lungs. Patients taking PZA require close monitoring throughout therapy because PZA affects the liver and hepatotoxicity remains a risk.
References
- Centers for Disease Control and Prevention: "Turberculosis: Treatment"
- "Pearson Nurse's Drug Guide 2010"; Wilson, B. A., Shannon, T. M., & Shields, K. M.; 2010
- "American Nurse Today"; Tuberculosis Today: Fighting an Ancient Adversary; Rebecca Ruppert, RN; November 2007
