Ethambutol & Isoniazid Tablets 800/300 Mg

What Are Ethambutol & Isoniazid Tablets 800/300 mg?

Ethambutol & Isoniazid Tablets 800/300 mg combine two key antitubercular agents:

• Ethambutol (800 mg) – a bacteriostatic antitubercular agent that disrupts the synthesis of arabinogalactan, a crucial component of the Mycobacterium tuberculosis cell wall.

• Isoniazid (300 mg) – a bactericidal antibiotic that inhibits mycolic acid synthesis, an essential part of the mycobacterial cell wall.

Together, they are administered as part of combination antitubercular therapy to reduce bacterial load, avoid drug resistance, and support effective treatment of TB.

How the Combination Works

Ethambutol Mechanism

Ethambutol interferes with arabinogalactan synthesis in the mycobacterial cell wall, slowing bacterial growth and making the organism more susceptible to companion drugs in the regimen.

Isoniazid Mechanism

Isoniazid inhibits the synthesis of mycolic acids, essential components of the mycobacterial cell wall. This action is bactericidal against actively dividing TB bacteria.

This combination enhances effectiveness when used with other first-line medicines (such as rifampicin and pyrazinamide), and reduces the likelihood of drug resistance developing.

Indications

Ethambutol & Isoniazid Tablets 800/300 mg are indicated for:

• Pulmonary tuberculosis

• Extrapulmonary tuberculosis

• Initial and continuation phases of TB therapy

• Use only as part of a multidrug antitubercular regimen

It should never be used alone or empirically without a confirmed diagnosis and prescription by a qualified healthcare provider.

Dosage & Administration

• Typical adult dose: One tablet once daily or as determined by your clinician

• Tablets should be taken with a full glass of water

• May be taken with food if gastrointestinal discomfort occurs

• Patients must complete the full course of therapy as prescribed to ensure efficacy and prevent resistance

The exact duration and regimen are determined based on disease severity, weight, and clinical response.

Safety Information & Precautions

Vision Monitoring

Ethambutol may cause optic neuritis, which can affect visual acuity and colour discrimination. Before initiating therapy and periodically during treatment, patients should undergo:

• Visual acuity testing

• Colour vision evaluation

Report any visual changes promptly to a healthcare professional.

Hepatic Monitoring

Isoniazid can cause hepatotoxicity, especially in older adults and individuals with pre-existing liver disease. Liver function tests should be monitored before and during treatment.

Before Using This Medicine

Inform your healthcare provider if you have:

• A history of liver disease

• Pre-existing eye problems

• Alcohol use or chronic illness

• Allergies to antibiotics or TB medicines

Common Side Effects

Possible side effects may include:

• Visual disturbances (blurred vision, colour vision changes)

• Gastrointestinal discomfort

• Peripheral neuropathy

• Elevated liver enzymes

• Loss of appetite

• Fatigue

Seek medical evaluation for severe symptoms, particularly vision changes or signs of liver dysfunction such as jaundice or persistent nausea.

Drug Interactions

Ethambutol & Isoniazid combination may interact with:

• Antacids (especially aluminum-based)

• Rifampicin and pyrazinamide as part of regimen — require coordinated monitoring

• Phenytoin or other anticonvulsants

• Alcohol — may increase risk of liver toxicity

Always share a full list of current medications and supplements with your healthcare provider.

Storage Instructions

Store Ethambutol & Isoniazid Tablets 800/300 mg in a cool, dry place below 25°C, away from direct sunlight and moisture. Keep out of reach of children and pets.

FAQs