Podcast
Questions and Answers
What is the classification of isoniazid?
What is the mechanism of action of isoniazid?
Highly selective for M. tuberculosis, can kill at concentrations 10,000 times lower than those needed to affect gram-positive and gram-negative bacteria.
When is isoniazid bactericidal?
To actively dividing mycobacteria.
When is isoniazid bacteriostatic?
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How does isoniazid work?
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TB can develop resistance to isoniazid.
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What is acquired resistance?
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How is emergent resistance reduced?
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If an organism is resistant to isoniazid, what is it also resistant to?
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Why use isoniazid?
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How do you treat latent TB with isoniazid?
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How do you treat active TB with isoniazid?
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What are the adverse reactions to isoniazid?
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What causes peripheral neuropathy with isoniazid?
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Study Notes
Isoniazid Overview
- First-line anti-tuberculosis (TB) drug, effective against Mycobacterium tuberculosis.
Mechanism of Action
- Highly selective for Mycobacterium tuberculosis.
- Can kill bacteria at concentrations 10,000 times lower than required for gram-positive or gram-negative bacteria.
Bactericidal Activity
- Isoniazid is bactericidal against actively dividing mycobacteria.
Bacteriostatic Activity
- Isoniazid acts as bacteriostatic against resting bacteria.
How It Works
- Suppresses bacterial growth by inhibiting the synthesis of mycolic acid, an essential component of the mycobacterial cell wall.
Resistance Issues
- Tuberculosis can develop resistance to isoniazid.
Acquired Resistance
- Acquired resistance results from spontaneous mutations rather than the transfer of resistance factors.
Emergent Resistance
- Reduced emergence of resistance occurs through the use of multi-drug regimens.
Cross-Resistance
- Organisms that are resistant to isoniazid are also resistant to ethionamide.
Indications for Use
- Used solely for the treatment of active and latent tuberculosis.
Treatment of Latent TB
- Can be administered alone or in combination with rifapentine.
Treatment of Active TB
- Must be taken with at least one other antitubercular agent.
Adverse Reactions
- Potential side effects include hepatotoxicity, peripheral neuropathy (most common), CNS effects, anemia, gastrointestinal distress, dry mouth, urinary retention, and allergic reactions.
Cause of Peripheral Neuropathy
- Peripheral neuropathy associated with isoniazid is due to a deficiency in pyridoxine (vitamin B6).
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Description
Explore key concepts about isoniazid, a first-line anti-TB drug, through this quiz. Understand its classification, mechanism of action, and when it acts as bactericidal or bacteriostatic. Perfect for students and healthcare professionals looking to deepen their knowledge of tuberculosis treatment.
