Isoniazid Flashcards

Questions and Answers

What is the classification of isoniazid?

Not used for TB

First line anti-TB drug (correct)

Second line anti-TB drug

Vaccine

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?

To resting agents. Signup and view all the answers

How does isoniazid work?

By suppressing bacterial growth by inhibiting synthesis of mycolic acid, a component of the mycobacterial cell wall. Signup and view all the answers

TB can develop resistance to isoniazid.

True Signup and view all the answers

What is acquired resistance?

Results from spontaneous mutations, not from transfer of R factors. Signup and view all the answers

How is emergent resistance reduced?

Through multi-drug resistance. Signup and view all the answers

If an organism is resistant to isoniazid, what is it also resistant to?

Ethionamide. Signup and view all the answers

Why use isoniazid?

Only for treating active and latent TB. Signup and view all the answers

How do you treat latent TB with isoniazid?

Administered alone or with rifapentine. Signup and view all the answers

How do you treat active TB with isoniazid?

Must be taken with at least one other agent. Signup and view all the answers

What are the adverse reactions to isoniazid?

Hepatotoxicity, peripheral neuropathy, CNS effects, anemia, GI distress, dry mouth, urinary retention, and allergies. Signup and view all the answers

What causes peripheral neuropathy with isoniazid?

Deficiency in pyridoxine. Signup and view all the answers

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).

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.