Isoniazid 100 mg Tablet: Comprehensive Guide
Clinical Reference Standards: CDSCO (Central Drugs Standard Control Organisation), Indian Pharmacopoeia (IP) & WHO | Last Updated: September 2026
When to Call Your Doctor IMMEDIATELY
- Yellowing of skin or eyes (jaundice)
- Dark urine or pale stools
- Severe abdominal pain
- Persistent nausea and vomiting
- Seizures
- Vision changes
- Severe skin rash or allergic reaction
- Unexplained fatigue or weakness
If experiencing severe symptoms, call emergency services immediately.
What is isonex 100mg tablet used for?
Isoniazid is an antibiotic used to treat and prevent tuberculosis. It works by killing the bacteria that cause TB. It is usually taken as part of a combination regimen.
- Generic Name: Isoniazid (100mg)
- Manufacturer: Pfizer Ltd
- Form: Allopathy
- Pregnancy Category: Consult doctor
- Prescription Required: Yes
🇮🇳 isonex 100mg tablet के बारे में (Hindi Summary)
उपयोग: यह दवा तपेदिक (टीबी) के इलाज और रोकथाम के लिए इस्तेमाल की जाती है। यह एक एंटीबायोटिक है जो टीबी पैदा करने वाले बैक्टीरिया को मारती है। यह अक्सर अन्य दवाओं के साथ मिलकर दी जाती है।
साइड इफेक्ट्स: आम दुष्प्रभावों में मतली, उल्टी, पेट दर्द, और भूख न लगना शामिल हैं। कुछ रोगियों को हाथ-पैरों में झुनझुनी या सुन्नपन महसूस हो सकता है। गंभीर दुष्प्रभावों में लिवर की समस्या, दौरे, और दृष्टि में बदलाव शामिल हैं। कोई भी असामान्य लक्षण दिखने पर तुरंत डॉक्टर से संपर्क करें।
सुरक्षा सलाह: इस दवा को डॉक्टर के बताए अनुसार ही लें। उपचार पूरा होने से पहले दवा बंद न करें। शराब का सेवन न करें क्योंकि इससे लिवर को नुकसान हो सकता है। नियमित रूप से लिवर फंक्शन टेस्ट करवाएं। गर्भवती महिलाएं डॉक्टर से सलाह लें।
💊 isonex 100mg tablet Uses & Benefits
[{"condition":"Active Tuberculosis","description":"Used in combination with other antitubercular drugs (e.g., rifampicin, pyrazinamide, ethambutol) for the treatment of active TB.","evidence":"Well-established"},{"condition":"Latent Tuberculosis Infection","description":"Used as a single agent to prevent progression to active TB in individuals with latent infection.","evidence":"Well-established"},{"condition":"Tuberculosis Meningitis","description":"Part of combination therapy for TB meningitis, often with extended treatment duration.","evidence":"Well-established"},{"condition":"Disseminated Tuberculosis","description":"Included in regimens for disseminated or miliary TB.","evidence":"Well-established"}]
Off-label uses: [{"condition":"Atypical Mycobacterial Infections","description":"Sometimes used off-label for certain nontuberculous mycobacterial infections, though not first-line.","evidence":"Limited"}]
Primary treatment for: Tuberculosis
Also treats: Latent Tuberculosis Infection, Tuberculous Meningitis, Disseminated Tuberculosis
📋 Drug Information
| Generic Name(s) | Isoniazid (100mg) |
| Brand Name | isonex 100mg tablet |
| Manufacturer | Pfizer Ltd |
| Packaging / Form | Varies by brand (Allopathy) |
| Therapeutic Class | ANTI INFECTIVES |
| Action Class | Mycolic acid inhibitors- INH |
| Route of Administration | Oral |
| Storage | Store at room temperature (15-30°C) in a dry place, away from direct sunlight. Keep in the original container. |
| Shelf Life | 24 months from the date of manufacture. |
| WHO Guideline | WHO recommends Isoniazid as part of first-line treatment for tuberculosis. For latent TB, Isoniazid preventive therapy is recommended for certain high-risk groups. |
| ICMR Guideline | ICMR guidelines recommend Isoniazid as part of standard antitubercular therapy. Regular monitoring for hepatotoxicity is advised. |
👨⚕️ Doctor's Practical Tips
Evidence-based practical advice from experienced clinicians
🔍 Is This Medicine Right for Your Symptom?
Educational reference. Always consult a doctor for diagnosis.
🔬 How This Medicine Works (Pharmacology)
Pharmacokinetics
How It Works
Isoniazid is a prodrug that is activated by the bacterial catalase-peroxidase enzyme KatG. The activated form inhibits the enoyl-acyl carrier protein reductase (InhA), which is essential for the synthesis of mycolic acid, a key component of the mycobacterial cell wall. This leads to disruption of cell wall synthesis and bacterial death. Isoniazid is bactericidal against actively dividing Mycobacterium tuberculosis and is also active against dormant organisms.
Mechanism Steps
💡 How to Take isonex 100mg tablet
Strength: Dispersible tablet, 100 mg
Dosage Information
| Adult Dosage | The usual adult dose for active tuberculosis is 5 mg/kg per day (up to 300 mg) in combination with other antitubercular drugs. For latent TB infection, the dose is 300 mg daily for 6-9 months, or as directed by the physician. Dose must be individualized by a qualified clinician based on indication, age, weight, renal and hepatic function. |
| Pediatric Dosage | Pediatric dosing is not established from available information. Consult a pediatrician. |
| Elderly Dosage | Elderly patients may require dose adjustment based on renal and hepatic function. Monitor closely for side effects. |
| Renal Impairment | Dose adjustment may be needed in severe renal impairment. Consult a clinician. |
| Hepatic Impairment | Use with caution in patients with hepatic impairment. Dose reduction may be necessary. Monitor liver function closely. |
| Maximum Daily Dose | 300 mg per day for adults. |
Dosage Timeline
🍽️ Food Timing Guide
⏰ What to Do If You Miss a Dose
⚠️ Side Effects of isonex 100mg tablet
✅ Common Side Effects
🚨 Serious Side Effects
⚠️ Rare Side Effects
Consult your doctor if you experience any unusual symptoms.
🔬 Drug Interactions
| Drug | Severity | Effect |
|---|---|---|
| Rifampicin | Major | |
| Phenytoin | Major | |
| Carbamazepine | Major | |
| Warfarin | Major | |
| Alcohol | Moderate | |
| Acetaminophen | Moderate | |
| Ketoconazole | Moderate | |
| Antacids | Minor |
🚨 Major Interactions
- Rifampicin
- Phenytoin
- Carbamazepine
- Warfarin
⚡ Moderate Interactions
- Alcohol
- Acetaminophen
- Ketoconazole
🍷 Alcohol Interaction
Alcohol should be avoided while taking this medicine because it increases the risk of hepatotoxicity. Both Isoniazid and alcohol are metabolized by the liver, and their combined use can lead to severe liver damage.
🔎 Check Your Other Medicines
Educational tool. Always confirm with your doctor or pharmacist.
🛡️ Safety & Warnings
🚫 Contraindications
["Hypersensitivity to Isoniazid or any component of the formulation","Acute liver disease","Previous Isoniazid-induced hepatitis","Severe renal impairment without dose adjustment"]
⚠️ Warnings & Precautions
["Hepatotoxicity: Monitor liver function closely. Discontinue if signs of liver damage occur.","Peripheral neuropathy: Supplement with pyridoxine (vitamin B6) as needed.","Alcohol use: Avoid alcohol to reduce risk of liver damage.","Drug interactions: Inform doctor of all medications being taken.","Pregnancy: Use with caution; pyridoxine supplementation recommended.","Breastfeeding: Monitor infant for signs of toxicity.","Renal impairment: Dose adjustment may be required.","Elderly: Increased risk of hepatotoxicity; monitor closely."]
🤱 Lactation Safety
Isoniazid is excreted in breast milk in small amounts. It is generally considered safe during breastfeeding, but the infant should be monitored for signs of toxicity. Pyridoxine supplementation for the infant may be considered.
💊 Overdose Management
Overdose of Isoniazid can cause nausea, vomiting, dizziness, slurred speech, seizures, and metabolic acidosis. Immediate medical attention is required. Treatment includes activated charcoal if within 1-2 hours of ingestion, intravenous pyridoxine, and supportive care. Hemodialysis may be considered in severe cases.
⏰ Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not double the dose to catch up.
Additional Safety Advice
Take this medicine exactly as prescribed by your doctor. Do not skip doses or stop treatment early, even if you feel better. This medicine is usually taken on an empty stomach, but if it causes stomach upset, you may take it with food. Avoid alcohol consumption while on this medicine as it increases the risk of liver damage. Regular monitoring of liver function tests is recommended, especially during the first few months of treatment. Inform your doctor if you have a history of liver disease, alcohol abuse, or are taking other medications that affect the liver. If you are pregnant or planning to become pregnant, consult your doctor before taking this medicine. Do not share this medicine with others, even if they have similar symptoms. Keep this medicine out of reach of children.
👴 Special Considerations for Elderly
💡 For Patients Above 65
Elderly patients are at higher risk of hepatotoxicity and peripheral neuropathy. Close monitoring of liver function and neurological symptoms is recommended. Dose adjustment may be necessary based on renal and hepatic function.
🤰 Pregnancy Planning (TTC)
If you are planning to become pregnant, consult your doctor. Isoniazid is generally considered safe during pregnancy, but pyridoxine supplementation is recommended. Untreated TB poses greater risks to both mother and fetus.
🏥 Post-Surgery Considerations
Inform your surgeon and anesthesiologist that you are taking this medicine. It may interact with other medications used during surgery. Continue taking it as prescribed unless instructed otherwise.
🦷 Dental Procedures
Inform your dentist that you are taking this medicine. It may interact with certain antibiotics or anesthetics. Maintain good oral hygiene to prevent infections.
💚 Lifestyle Tips for Better Results
🏋️ Exercise Considerations
Moderate exercise is generally safe while taking this medicine. However, if you experience dizziness or fatigue, avoid strenuous activities until you feel better. Consult your doctor before starting any new exercise regimen.
🥗 Diet Recommendations
💼 Impact on Daily Work & Life
This medicine may cause dizziness or fatigue in some people. If affected, avoid driving or operating heavy machinery until you know how it affects you. Otherwise, it should not significantly impact your daily activities.
🛑 When to Stop This Medicine
Do not stop taking this medicine without consulting your doctor. Stopping early can lead to treatment failure and drug resistance. If you experience severe side effects, contact your doctor immediately for guidance.
📅 Long-Term Use Effects
Long-term use of Isoniazid may lead to peripheral neuropathy, which can be prevented with pyridoxine supplementation. Regular monitoring of liver function is essential as hepatotoxicity can occur. With proper monitoring and adherence, long-term use is generally safe and effective for treating tuberculosis.
🌿 Non-Medicine Approaches
These can complement medicine but do not replace prescribed treatment.
A healthy diet can support immune function during TB treatment.
Evidence: Well-establishedPrevents peripheral neuropathy caused by Isoniazid.
Evidence: Well-established💉 Vaccination Considerations
💉 If You're Getting Vaccinated
Isoniazid may reduce the efficacy of live vaccines. Consult your doctor before receiving any vaccinations while on this medicine.
📦 Storage Guide
✅ DO
Store at room temperature (15-30°C)
❌ DON'T
Do not refrigerate unless specified
✅ DO
Keep in original container
❌ DON'T
Do not transfer to unmarked containers
✅ DO
Keep away from direct sunlight
❌ DON'T
Do not store in bathroom cabinet
✈️ Traveling with This Medicine
When traveling, carry your medicine in its original packaging along with a copy of your prescription. Ensure you have enough supply for the entire trip. Store at room temperature and avoid extreme heat or moisture. If crossing time zones, adjust dosing times gradually in consultation with your doctor. Check customs regulations for carrying prescription medications.
💰 Cost Analysis & Savings
👥 Real Patient Stories
Educational, anonymized scenarios. Individual results may vary.
💬 Questions Patients Often Ask
A: It may take several weeks to see improvement in symptoms. Complete the full course as prescribed.
A: No, you must complete the full course to prevent relapse and resistance.
A: Take it as soon as you remember, but if it's almost time for the next dose, skip the missed dose. Do not double dose.
🤔 Common Patient Concerns
🔄 Substitutes for isonex 100mg tablet
View AllAlternative brands with exact same active ingredient:
Medical Note: Always consult your doctor before switching medications.
🛑 Myths vs. Facts
- Myth: Isoniazid can be stopped once symptoms improve.
Fact: Treatment must be completed as prescribed to prevent relapse and resistance. - Myth: Isoniazid is safe to take with alcohol.
Fact: Alcohol increases the risk of liver damage and should be avoided.
🔄 Alternative Options
Generic Alternatives
- Isoniazid 100 mg tablet
- Isoniazid 300 mg tablet
Brand Alternatives
- Solonex DT Tablet
- Isokin Tablet
- INH Tablet