Tuberculosis Treatment: Basic Knowledge and Important Information

1. Introduction

Tuberculosis (TB) is an infectious disease caused by the bacteria Mycobacterium tuberculosis (TB bacteria). It can affect many organs in the body, but most commonly affects the lungs. TB treatment involves using anti-TB drugs to kill the TB bacteria and prevent the disease from returning.

2. Anti-TB Medications

2.1. The 5 Main Anti-TB Drugs:

• R: Rifampicin

• H: Isoniazid

• Z: Pyrazinamide

• E: Ethambutol

• S: Streptomycin

2.2. Available Forms:

• Primarily Oral Tablets: This is convenient for patients, easy to use, and multiple medications can be combined in a single pill.

• Injectable Form: Mainly for Streptomycin.

2.3. Characteristics of TB Bacteria:

• Drug Resistance Mutations: TB bacteria can mutate and develop resistance to medications, making treatment complex and challenging.

• Bacterial Metabolism: TB bacteria have different metabolic phases, requiring the use of drugs that are effective at different stages to eradicate them.

2.4. Drug Resistance:

• Natural Resistance: TB bacteria can develop resistance to drugs from the beginning. This happens with all anti-TB drugs.

• Secondary Resistance: Using a single drug can lead to the elimination of sensitive bacteria, allowing resistant bacteria to thrive and multiply.

2.5. Preventing Drug Resistance:

• Combining Anti-TB Drugs: Using multiple medications simultaneously helps to kill any bacteria that may be resistant to individual drugs.

• Complete the Full Course, at the Right Time: This maintains a consistent drug level in the blood, killing the TB bacteria and preventing drug resistance.

2.6. TB Bacterial Populations in Lesions:

• Up to 4 Population Types A, B, C, D: Each population has different characteristics in terms of location, metabolism, and drug sensitivity.

2.7. Treatment Principles:

• Two-Phase Treatment:

• Initial Phase (Attack Phase): Aims to quickly reduce the number of bacteria and eliminate Population A, using multiple drugs.

• Continuation Phase (Maintenance Phase): Targets the remaining populations, using fewer medications but ensuring at least one bactericidal drug to prevent recurrence.

2.8. Pharmacokinetics:

• Drug Selection Criteria: High serum concentrations, exceeding factor >= 20, and good tissue penetration are crucial.

• Drug Penetration: Each drug has different penetration abilities into various tissues of the body.

• Taking Medication on an Empty Stomach: Minimizes drug breakdown by digestive enzymes.

• Taking Medications Simultaneously: Reduces drug binding to proteins in the blood.

2.9. Drug Classification:

• Based on Action on Bacteria: Bactericidal (R, Z) and bacteriostatic (E, Thiacetzon)

• Based on Mechanism of Action: Inhibit DNA transcription, inhibit protein synthesis, disrupt membranes.

• Based on WHO Classification: 5 groups:

• Group 1: Essential Anti-TB Drugs (First-line)

• Group 2: Second-line Injectable Anti-TB Drugs

• Group 3: Second-line Fluoroquinolone Anti-TB Drugs

• Group 4: Oral Second-line Anti-TB Drugs

• Group 5: Drugs with Unclear Efficacy, Including New Drugs.

2.10. Advantages and Disadvantages of Combined Tablets:

• Advantages: Enhances treatment adherence, lowers the risk of selective drug resistance.

• Disadvantages: Drug concentrations may be inconsistent, dosage is not always guaranteed, and it can be difficult to identify drug allergies.

2.11. Detailed Information on Individual Medications:

• S (Streptomycin):

• Presentation: 1g

• Action: Kills extra-cellular bacteria, ineffective against TB within cells.

• Metabolism: Slowly excreted through the kidneys (can cause kidney toxicity).

• Dosage: Intramuscular injection 15-20mg/kg, maximum 1g/day.

• Z (Pyrazinamide):

• Presentation: 0.5g

• Action: Kills intracellular TB bacteria, effective in acidic environments.

• Metabolism: Excreted primarily through the kidneys.

• Dosage: 30-40mg/kg

• E (Ethambutol):

• Presentation: 0.4g

• Action: Bacteriostatic, needs to be combined with other drugs.

• Metabolism: Excreted through the kidneys.

• Dosage: 25mg/kg

• R (Rifampicin):

• Presentation: 0.15g; 0.3g

• Action: Kills rapidly growing bacteria, sterilizes slowly growing bacteria.

• Metabolism: Through the liver, with enterohepatic circulation.

• Dosage: 10 – 20 mg/kg

• H (Isoniazid):

• Presentation: 0.05, 0.1, 0.15, 0.3g

• Action: Kills TB bacteria both inside and outside cells (rapidly dividing bacteria).

• Metabolism: Through the liver.

• Dosage: 4 – 6 mg/kg

3. TB Treatment Regimens:

• General Principles: Combine medications, use the correct dosage, administer regularly, for a sufficient duration, following two phases: Initial and Continuation.

• Treatment Goals:

• Initial Phase: Rapidly reduce bacterial numbers and eliminate drug-resistant bacteria.

• Continuation Phase: Eliminate all TB bacteria, preventing recurrence.

• Regimen I:

• IA (A1): 2RHEZ/4RHE –> New pulmonary TB without drug resistance

• IB (A2): 2RHEZ/4RH –> New pulmonary TB with drug resistance

• Regimen II: 2SRHZE/1RHZE/5(RHE)3 –> Relapse TB, TB requiring re-treatment

• Regimen III:

• IIIA (B1): 2RHZE/10RHE –> Extrapulmonary TB, bone and joint TB without drug resistance

• IIIB (B2): 2RHZE/10RH –> Extrapulmonary TB, bone and joint TB with drug resistance

• Multidrug-Resistant TB Treatment Regimen: (not covered)

• TB Treatment During Pregnancy: Avoid Streptomycin, consider B6 25mg/day if using INH.

• TB Treatment in Patients with Liver Disease:

• Hospitalization during severe stages.

• Monitor liver function tests.

• TB Treatment in Patients with Kidney Failure:

• Regimen: 2RHZ/ 4RH

• Adjust E and S dosages based on glomerular filtration rate.

4. Corticosteroid Treatment:

• Indications: Extrapulmonary TB, pericarditis, TB meningitis.

• Dosage: 4-8 weeks

• Week 1: 0.4mg/kg intravenous injection

• Reduce by 0.1mg/kg per week

• From week 5, switch to oral medication with a dosage of 4mg, reducing by 1mg per week

5. Treatment Monitoring:

• Medication Monitoring: Ensure patients take their medication completely and on time.

• Treatment Response Monitoring: Monitor clinical symptoms, X-rays, and drug side effects.

• Sputum Tests: Months 2, 5, 6.

• Switch to Drug-Resistant Treatment Regimen: When TB bacteria resistance is detected.

6. Drug Side Effects:

• R, H: Hepatitis, acute liver failure

• S: Prolonged treatment can cause deafness.

• E: Decreased vision, color blindness.

• Hemolysis

7. Important Notes:

• TB treatment should be supervised by a specialist physician.

• Do not stop medication or change dosages without a doctor’s instructions.

• Strictly follow the treatment regimen.

• Regularly monitor health status and drug side effects.

• Regular TB screening is necessary for early detection and treatment.

8. Additional Information:

• New Medications: Bedaquiline, Delamanid

• Currently, TB without evidence of drug resistance is treated with regimen A1 or A2 for all stages. For extrapulmonary TB and bone and joint TB, regimen B1 or B2 is used.

9. Conclusion:

TB treatment is a complex process that requires patient persistence and strict adherence. Using medication correctly, following the regimen, and regular treatment monitoring are crucial factors in helping patients recover and prevent recurrence.