Isoniazid 300 mg is an antibacterial medication used for the treatment and prevention of tuberculosis (TB). It works by inhibiting the growth of the bacteria that cause tuberculosis. Isoniazid is usually used as part of a combination treatment regimen with other anti-tuberculosis medications to help prevent bacterial resistance and achieve the best therapeutic outcomes.
What is isoniazid 300 mg used for?
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Treatment of active tuberculosis as part of a multi-drug treatment regimen.
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Prevention of active tuberculosis in individuals at risk of developing the disease or those with latent tuberculosis infection (LTBI).
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Helps eliminate tuberculosis bacteria and reduce the spread of infection.
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Can be used in both adults and children according to a physician’s recommendations.
Isoniazid dosage for adults
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Use exactly as prescribed by your doctor.
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It is usually taken on an empty stomach, either 1 hour before or 2 hours after meals, unless otherwise directed by your physician.
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Take the medication at the same time each day.
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Complete the full course of treatment even if symptoms improve.
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Your doctor may prescribe a vitamin B6 (Pyridoxine) supplement during treatment to reduce the risk of nerve-related side effects.
Important Note:
Isoniazid is a prescription-only medication and should be used under the supervision of a qualified healthcare professional, with regular follow-up visits and laboratory monitoring throughout the treatment period.
Isoniazid side effects
Possible side effects may include:
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Nausea or stomach upset.
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Loss of appetite.
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Fatigue or general weakness.
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Headache or dizziness.
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Numbness or tingling in the hands and feet.
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Elevated liver enzymes or hepatitis in some cases.
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Allergic reactions such as skin rash (rare).
Precautions and Warnings
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Do not use if you are allergic to isoniazid.
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Inform your doctor if you have liver disease or a history of hepatitis.
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Alcohol consumption may increase the risk of liver damage during treatment.
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Regular liver function monitoring is recommended, especially for older adults and patients with risk factors.
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Contact your doctor immediately if you develop symptoms such as yellowing of the skin or eyes, dark urine, or severe abdominal pain.
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Use during pregnancy or breastfeeding only if recommended by a healthcare professional.
Drug Interactions
Isoniazid may interact with:
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Phenytoin.
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Carbamazepine.
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Warfarin.
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Certain antifungal medications.
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Rifampin (Rifampicin).
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Antacids.
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Acetaminophen (Paracetamol).
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Alcohol.
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Other anti-tuberculosis medications.
Therefore, inform your doctor or pharmacist about all medications, supplements, and herbal products you are taking before starting treatment.
Storage and Handling
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Store at room temperature (generally below 25–30°C).
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Keep away from moisture and direct heat.
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Store in the original, tightly closed container.
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Keep out of reach of children.
Ingredients
Active Ingredient:
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Isoniazid 300 mg per tablet.
Inactive Ingredients:
Inactive ingredients may vary depending on the manufacturer and commonly include:
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Lactose.
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Starch.
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Microcrystalline cellulose.
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Magnesium stearate.
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Other excipients used in tablet formulation.
Frequently Asked Questions
Can I Take Isoniazid If I Do Not Have Active Tuberculosis?
Yes. In some cases, a doctor may prescribe Isoniazid to individuals who do not have active tuberculosis but have latent tuberculosis infection (LTBI) or are at high risk of developing active TB. In these situations, the medication is used to help prevent latent infection from progressing to active tuberculosis in the future.
