Pharmacotherapy for tuberculosis TB

The pharmacotherapy for tuberculosis (TB) typically involves a combination of antibiotics over an extended period. The most common regimen for drug-sensitive TB includes the following first-line anti-TB drugs:

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Isoniazid (INH):
- Mechanism: Inhibits mycolic acid synthesis in the bacterial cell wall.
- Adverse Drug Reactions (ADRs):
  - Hepatotoxicity (hepatitis, jaundice)
  - Peripheral neuropathy (often due to vitamin B6 deficiency; can be managed with pyridoxine)
  - Rash
  - Fever
  - Rarely, CNS effects (seizures, psychosis)
Rifampin (RIF):
- Mechanism: Inhibits bacterial RNA polymerase.
- ADRs:
  - Hepatotoxicity
  - Red-orange discoloration of bodily fluids (urine, sweat, tears)
  - Gastrointestinal symptoms (nausea, vomiting)
  - Rash
  - Rarely, flu-like symptoms
Ethambutol (EMB):
- Mechanism: Inhibits the synthesis of the cell wall by blocking arabinogalactan formation.
- ADRs:
  - Optic neuritis (can cause decreased visual acuity and red-green color blindness)
  - Rash
  - Gastrointestinal symptoms (nausea, vomiting)
  - Hepatotoxicity (less common)
Pyrazinamide (PZA):
- Mechanism: Disrupts mycobacterial cell membrane metabolism and transport functions.
- ADRs:
  - Hepatotoxicity
  - Hyperuricemia (can lead to gout)
  - Gastrointestinal symptoms (nausea, vomiting)
  - Rash
  - Arthralgia

Treatment Duration

Initial Phase: Typically lasts 2 months and includes all four drugs (INH, RIF, EMB, PZA).
Continuation Phase: Lasts 4 to 6 months and usually includes INH and RIF.

Monitoring

Patients on TB therapy need regular monitoring for side effects and efficacy, including liver function tests and visual acuity assessments, especially when using drugs like INH and EMB.

For drug-resistant TB or specific patient conditions, alternative regimens and second-line drugs may be used, which come with their own sets of potential side effects and considerations.