Isoniazid

Isoniazid

Isoniazid is one of the key medicines for treating tuberculosis. It works as a first line defence against active as well as latent TB infections. This medicine activates inside the body and stops the synthesis of the mycobacterial cell wall. This wall halts the progression of infection in your body. Patients can take it as tablets, syrup, or an injectable solution based on their needs. This article explains what this essential TB medication is, proper usage, and safety precautions.

What is Isoniazid?

Isoniazid acts as a prodrug that bacterial catalase must activate. The activated drug blocks mycolic acid formation, which tuberculosis bacteria need for their cell wall. This medicine effectively fights bacteria from the Mycobacterium genus, especially M. tuberculosis, M. bovis and M. kansasii. Other microorganisms remain unaffected by it.

Isoniazid Tablet Uses

This medication treats all types of pulmonary and extra-pulmonary tuberculosis. Patients use it to treat active TB infection and prevent latent TB progression. Doctors prescribe it to high-risk patients such as:

• HIV-positive patients with positive TB skin tests
• People who recently had close contact with TB patients
• Patients who have fibrotic pulmonary lesions

How and When to Use Isoniazid Tablet

• You should take this medication with water on an empty stomach - either 30 minutes before meals or 2 hours after. 
• Take the whole tablet with a glass of water do not crush or split the tablet.
• Always take the medicine at the same time each day (if needed set an alarm to remember). 
• Do not skip the medicine as skipping doses can lead to drug resistance.
• Do not stop the treatment on your own especially if you feel better after a few weeks. Stopping treatment early can lead to treatment failure.

Side Effects of Isoniazid Tablet

Patients often experience nausea, vomiting and stomach discomfort. Serious side effects:

• Liver damage 
• Peripheral neuropathy (hands and feet might feel numb or tingle)
• Rare but severe skin reactions

Precautions

• Patients need liver function tests before starting treatment. 
• People with liver problems, convulsive disorders, diabetes, chronic alcoholism, or kidney issues need extra monitoring. 
• Vitamin B6 supplements help prevent neuropathy in pregnant women, HIV patients, and malnourished individuals.
• Avoid alcohol during treatment as it may increase the risk of liver damage.
• Tell your doctor about every medicine you are taking.

How Isoniazid Tablet Works

Isoniazid acts as a prodrug that needs TB bacteria's catalase peroxidase (KatG) to get activated in our body. The activated drug creates compounds that stop the synthesis of mycolic acids. The drug binds with the NAD cofactor and creates INH-NAD, which tightly binds to InhA (the enzyme that forms cell walls). This makes isoniazid deadly against growing TB bacteria.

Can I Take Isoniazid with Other Medicines?

Isoniazid interacts with many medications, so patients need to be careful. These are:

• Acetaminophen 
• Carbamazepine 
• Diazepam
• Fosphenytoin
• Haloperidol
• Ketoconazole
• Methotrexate
• Phenytoin 
• Theophylline 
• Warfarin

Dosage Information

• Adult doses - 5-15 mg/kg two to three times weekly 
• Children - 10 mg/kg daily (up to 300 mg). 
• Adults over 30 kg usually take 300 mg daily for nine months to prevent latent TB. 

Conclusion

Isoniazid remains one of our strongest weapons against tuberculosis worldwide. It knows how to stop bacterial cell wall formation and fights active TB infections while preventing latent TB development. This powerful medication works against TB-causing bacteria but patients need to watch for potential liver issues during treatment.

Patients can take this drug as tablets, syrup or injections (available for different needs). The medication works well, but it comes with responsibilities. Safe treatment requires regular liver tests, precise dosing, and watchfulness for side effects.

Remember that successful TB treatment needs more than just having the right medicine. Patients must stick to their prescribed schedule because skipped doses can create dangerous drug resistance. Anyone taking this medication should follow their doctor's instructions and stay alert for unusual symptoms during treatment.

FAQs

1. Is isoniazid high risk?

Your risk depends on several factors. The chance of developing hepatitis (liver inflammation) goes up with age. Daily alcohol consumption increases these risks. Patients over 35 need regular monitoring.

2. Is isoniazid for anxiety?

No. Some antituberculars can trigger psychiatric reactions like mania and depression as side effects, but doctors don't prescribe isoniazid to treat anxiety.

3. How long does isoniazid take to work?

The treatment usually runs for 6-9 months. You will start with an 8-week intensive phase, then move to an 18-week continuation phase.

4. What happens if I miss a dose?

Take your missed dose as soon as you remember. Skip it if it's almost time for your next one and stick to your regular schedule. Never take two doses at once.

5. What happens if I overdose?

Taking over 1.5g can lead to mild toxicity. Larger doses (over 6-10g) could be fatal. Watch for symptoms like confusion, slurred speech and seizures. Get emergency medical help immediately.

6. What not to take with isoniazid?

Avoid:

• Alcohol - it can harm your liver
• St. John's wort - makes the medicine less effective
• Aluminium-based antacids - block proper absorption

7. Who cannot take isoniazid?

The medicine isn't safe for people with severe hypersensitivity reactions, previous isoniazid-related liver injury or acute liver disease.

8. At what time should I take isoniazid?

Take this medicine at the exact same time each day. Your bloodstream needs steady medication levels (so consistency matters a lot).

9. How many days to take isoniazid?

Treatment lasts 6 months to 2 years. Your doctor will decide the exact duration based on your condition.

10. At what time should I stop isoniazid?

Your doctor's approval is required before stopping. Stop immediately if you experience nausea, vomiting, stomach discomfort, or unusual tiredness. Contact your doctor immediately.

11. Is it safe to take isoniazid daily?

Yes. Adult patients typically take 300mg once daily. Some treatments need twice-weekly doses under direct observation.

12. What is the best time to take isoniazid?

Take tablets with water on an empty stomach - 30 minutes before meals or 2 hours after eating. Morning doses help you establish a routine.

13. What to avoid when taking isoniazid?

Stay away from:

• Alcohol 
• Foods with tyramine/histamine (aged cheese, tuna, red wine)

14. Why is isoniazid taken at night?

Night doses aren't specifically required. Take it at a consistent time that fits your schedule.

15. Can isoniazid cause weight gain?

Research shows no clear link between isoniazid and weight changes.