21 Anti Tubercular Agents Upd

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.

Antitubercular AgentsAntitubercular Agents



• Tuberculosis, “TB”Tuberculosis, “TB”

• Caused by Mycobacterium tuberculosisCaused by Mycobacterium tuberculosis

• Antitubercular agents treat all forms of Antitubercular agents treat all forms of mycobacteriummycobacterium


Mycobacterium InfectionsMycobacterium Infections

Common Infection SitesCommon Infection Sites

• lung (primary site)lung (primary site)

• brainbrain

• bonebone

• liverliver

• kidneykidney



• Aerobic bacillusAerobic bacillus

• Passed from infected:Passed from infected:

– HumansHumans

– Cows (bovine)Cows (bovine)

– Birds (avian)Birds (avian)



• Tubercle bacilli are conveyed by droplets.Tubercle bacilli are conveyed by droplets.

• Droplets are expelled by coughing or sneezing, Droplets are expelled by coughing or sneezing, then gain entry into the body then gain entry into the body by inhalation.by inhalation.

• Tubercle bacilli then spread to other body organs Tubercle bacilli then spread to other body organs via blood and lymphatic systems.via blood and lymphatic systems.

• Tubercle bacilli may become dormant, or walled Tubercle bacilli may become dormant, or walled off by calcified or fibrous tissue.off by calcified or fibrous tissue.



Primary AgentsPrimary Agents Secondary AgentsSecondary Agents

isoniazid*isoniazid* capreomycincapreomycin

ethambutolethambutol cycloserinecycloserine

pyrazinamide (PZA)pyrazinamide (PZA) ethionamideethionamide

rifampinrifampin kanamycinkanamycin

streptomycinstreptomycin para-aminosalicyclic para-aminosalicyclic acidacid (PSA)(PSA)

*most frequently used*most frequently used


Antitubercular Agents: Antitubercular Agents: Mechanism of ActionMechanism of Action

Three GroupsThree Groups

• Protein wall synthesis inhibitors streptomycin, Protein wall synthesis inhibitors streptomycin, kanamycin, capreomycin, rifampin, rifabutinkanamycin, capreomycin, rifampin, rifabutin

• Cell wall synthesis inhibitors cycloserine, Cell wall synthesis inhibitors cycloserine, ethionamide, isoniazidethionamide, isoniazid

• Other mechanisms of actionOther mechanisms of action


Antitubercular Agents:Antitubercular Agents:Mechanism of Action isoniazid (INH)Mechanism of Action isoniazid (INH)

• Drug of choice for TBDrug of choice for TB

• Resistant strains of mycobacterium emergingResistant strains of mycobacterium emerging

• Metabolized in the liver through acetylation—Metabolized in the liver through acetylation—watch for “slow acetylators”watch for “slow acetylators”


Used for the prophylaxisUsed for the prophylaxisor treatment of TBor treatment of TB

Antitubercular Agents:Antitubercular Agents:Therapeutic UsesTherapeutic Uses


Antitubercular TherapyAntitubercular Therapy

Effectiveness depends upon:Effectiveness depends upon:

• Type of infectionType of infection

• Adequate dosingAdequate dosing

• Sufficient duration of treatmentSufficient duration of treatment

• Drug complianceDrug compliance

• Selection of an effective drug combinationSelection of an effective drug combination


Antitubercular Agents: Side EffectsAntitubercular Agents: Side Effects

• INHINHperipheral neuritis, hepatotoxicityperipheral neuritis, hepatotoxicity

• ethambutolethambutolretrobulbar neuritis, blindnessretrobulbar neuritis, blindness

• rifampinrifampinhepatitis, discoloration of urine, stoolshepatitis, discoloration of urine, stools


Antitubercular Agents: Antitubercular Agents: Nursing ImplicationsNursing Implications• Obtain a thorough medical history and assessment.Obtain a thorough medical history and assessment.

• Perform liver function studies in patients Perform liver function studies in patients who are to receive isoniazid or rifampin who are to receive isoniazid or rifampin (especially in elderly patients or those who use (especially in elderly patients or those who use alcohol daily).alcohol daily).

• Assess for contraindications to the various agents, Assess for contraindications to the various agents, conditions for cautious use, and potential drug conditions for cautious use, and potential drug interactions.interactions.


Antitubercular Agents: Antitubercular Agents: Nursing ImplicationsNursing Implications

Patient education is CRITICAL:Patient education is CRITICAL:

• Therapy may last for up to 24 months.Therapy may last for up to 24 months.

• Take medications exactly as ordered, Take medications exactly as ordered, at the same time every day.at the same time every day.

• Emphasize the importance of strict compliance Emphasize the importance of strict compliance to regimen for improvement of condition or cure.to regimen for improvement of condition or cure.



Patient education is CRITICAL:Patient education is CRITICAL:

• Remind patients that they are contagious during Remind patients that they are contagious during the initial period of their illness—instruct in proper the initial period of their illness—instruct in proper hygiene and prevention of the spread of infected hygiene and prevention of the spread of infected droplets.droplets.

• Emphasize to patients to take care of themselves, Emphasize to patients to take care of themselves, including adequate nutrition and rest.including adequate nutrition and rest.



• Patients should not consume alcohol while on these Patients should not consume alcohol while on these medications nor take other medications, including medications nor take other medications, including OTC, unless they check with their physician.OTC, unless they check with their physician.

• Diabetic patients taking INH should monitor their Diabetic patients taking INH should monitor their blood glucose levels because hyperglycemia may blood glucose levels because hyperglycemia may occur.occur.

• INH and rifampin cause oral contraceptives to INH and rifampin cause oral contraceptives to become ineffective; another form of birth control become ineffective; another form of birth control will be needed.will be needed.



• Patients who are taking rifampin should be told that Patients who are taking rifampin should be told that their urine, stool, saliva, sputum, sweat, or tears may their urine, stool, saliva, sputum, sweat, or tears may become reddish-orange; even contact lenses may be become reddish-orange; even contact lenses may be stained.stained.

• Vitamin BVitamin B66 may is needed to combat peripheral may is needed to combat peripheral neuritis associated with INH therapy.neuritis associated with INH therapy.


Antitubercular Agents:Antitubercular Agents:Nursing ImplicationsNursing Implications

Monitor for side effectsMonitor for side effects

• Instruct patients on the side effects that should be Instruct patients on the side effects that should be reported to the physician immediately.reported to the physician immediately.

• These include fatigue, nausea, vomiting, numbness These include fatigue, nausea, vomiting, numbness and tingling of the extremities, fever, loss of appetite, and tingling of the extremities, fever, loss of appetite, depression, jaundice.depression, jaundice.


Antitubercular Agents:Antitubercular Agents:Nursing ImplicationsNursing Implications

Monitor for therapeutic effects:Monitor for therapeutic effects:

• Decrease in symptoms of TB, such as cough Decrease in symptoms of TB, such as cough and feverand fever

• Lab studies (culture and sensitivity tests) Lab studies (culture and sensitivity tests) and CXR should confirm clinical findingsand CXR should confirm clinical findings

• Watch for lack of clinical response to therapy, Watch for lack of clinical response to therapy, indicating possible drug resistanceindicating possible drug resistance

21 Anti Tubercular Agents Upd

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