Tb preventive therapy full details for md exams ntep
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TB preventive therapy TPT NTEP India regimens indications
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isoniazid preventive therapy latent TB treatment regimens 3HP 6H 1HP
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TPT contraindications active TB exclusion screening algorithm NTEP India 2022 2023
Here is a comprehensive, exam-oriented breakdown of TB Preventive Therapy (TPT) under NTEP (National TB Elimination Programme), India — integrating NTEP guidelines, WHO 2020 recommendations, and Harrison's 21st edition.
TB Preventive Therapy (TPT) — NTEP | Complete MD Exam Guide
1. CONCEPT & RATIONALE
- TPT = treatment given to prevent progression from latent TB infection (LTBI) → active TB disease
- Previously called: Isoniazid Preventive Therapy (IPT), Chemoprophylaxis, Preventive Chemotherapy
- Estimated 1.7 billion people worldwide have LTBI (>25% of global population) — the reservoir from which new TB cases emerge
- TPT is a pillar of TB elimination strategy under End TB strategy and National Strategic Plan (NSP) 2017–25
NTEP renamed "IPT" → "TPT" to reflect availability of multiple regimens beyond isoniazid alone
2. TYPES OF TPT
| Type | Definition |
|---|---|
| Primary prophylaxis | Given to LTBI-negative high-risk persons (e.g., HIV+ with no TB) to prevent initial infection or early disease |
| Secondary prophylaxis | Given to LTBI-positive persons to prevent reactivation |
3. WHO IS ELIGIBLE FOR TPT? (NTEP Priority Groups)
Category A — Mandatory (High Priority)
| Group | Details |
|---|---|
| PLHIV (People Living with HIV) | All ages, regardless of TST/IGRA result; after ruling out active TB |
| Household contacts of bacteriologically confirmed pulmonary TB | All ages |
| Child contacts < 5 years of any TB patient | Regardless of TST status |
| Child contacts 5–14 years | After ruling out active TB |
Category B — Recommended (Extended)
| Group |
|---|
| Patients on anti-TNF therapy (biologics) |
| Patients on dialysis |
| Silicosis patients |
| Transplant recipients (organ or stem cell) |
| Diabetes mellitus patients (selected) |
| Prisoners, healthcare workers in high-burden settings |
| Undernourished individuals |
Key NTEP Criteria for PLHIV:
- TST/IGRA NOT mandatory before starting TPT in PLHIV
- TPT started after ruling out active TB (not based on immunological testing)
4. RULING OUT ACTIVE TB BEFORE STARTING TPT
This is the most critical step. Use the W4SS (4-symptom screen):
Any one of: Cough, Fever, Night sweats, Weight loss
- If any symptom present → investigate for active TB first
- If all absent → proceed with TPT
- In PLHIV on ART: also consider chest X-ray + sputum examination if indicated
NTEP Algorithm:
Eligible person identified
↓
Screen for active TB (W4SS)
↓
Active TB ruled out?
YES → Start TPT
NO → Evaluate and treat active TB first
5. TPT REGIMENS — NTEP 2022 (Current Recommendations)
Primary Regimen for All Eligible Groups
| Regimen | Drug(s) | Duration | Frequency | Notes |
|---|---|---|---|---|
| 6H | Isoniazid (H) | 6 months | Daily | Long-standing standard; still used |
| 9H | Isoniazid | 9 months | Daily | Used in HIV+; WHO preferred alternative |
| 3HP ⭐ | Isoniazid + Rifapentine | 3 months | Weekly | NTEP preferred regimen; DOT required |
| 3HR | Isoniazid + Rifampicin | 3 months | Daily | Used where rifapentine unavailable |
| 1HP | Isoniazid + Rifapentine | 1 month | Daily | Alternative; conditional recommendation |
| 4R | Rifampicin alone | 4 months | Daily | For INH-intolerant patients |
NTEP Current Preferred Regimen:
3HP (3 months weekly Isoniazid + Rifapentine) — introduced under NTEP as the preferred short-course regimen due to better completion rates
Doses:
| Drug | Adult Dose | Pediatric Dose |
|---|---|---|
| Isoniazid (H) | 5 mg/kg/day (max 300 mg) | 10 mg/kg/day (max 300 mg) |
| Rifampicin (R) | 10 mg/kg/day (max 600 mg) | 15 mg/kg/day |
| Rifapentine (P) | Weight-based (see below) | ≥10 kg required |
Rifapentine weight-based dosing (3HP weekly):
- 10–14 kg: 300 mg
- 14–25 kg: 450 mg
- 25–32 kg: 600 mg
- 32–50 kg: 750 mg
-
50 kg: 900 mg (max)
6. FOR SPECIAL POPULATIONS
Children < 2 years (Household Contacts)
- Regimen: 6H (isoniazid daily × 6 months)
- TST not mandatory; clinical assessment sufficient
Children 2–5 years
- 6H or 3HP (if ≥10 kg body weight)
PLHIV
- All PLHIV should receive TPT (regardless of CD4 count, ART status, TST)
- Preferred: 3HP or 6H
- Interaction alert: Rifapentine + efavirenz — dose adjustment may be needed; rifabutin preferred if on certain PI-based ART
Pregnant Women
- TPT generally deferred until after delivery and completion of breastfeeding
- Exception: PLHIV with high risk — 6H preferred (rifamycins avoided in 1st trimester)
- Pyridoxine (Vitamin B6) 25–50 mg/day must be co-administered with isoniazid in pregnancy
Drug-Resistant TB Contacts (MDR-TB contacts)
- Standard TPT not recommended (isoniazid/rifampicin may be ineffective)
- Currently under 6–12 months of fluoroquinolone-based regimens (levofloxacin) in research/programmatic settings
- NTEP: monitor closely; no standardized DR-TPT regimen yet
7. MONITORING DURING TPT
| Parameter | Frequency |
|---|---|
| Active TB symptom screening | Every visit (monthly) |
| Hepatotoxicity symptoms (nausea, jaundice, abdominal pain) | Monthly |
| Liver function tests (LFTs) | Baseline; repeat if symptomatic or high risk |
| Pyridoxine supplementation | Given with INH in high-risk (alcoholics, DM, pregnancy, malnutrition, HIV) |
Stopping Rules:
- Jaundice or AST/ALT >3× ULN with symptoms → stop TPT
- AST/ALT >5× ULN (asymptomatic) → stop TPT
- Resume only after LFTs normalize
8. CONTRAINDICATIONS TO TPT
| Contraindication |
|---|
| Active TB disease (must treat first) |
| Severe hepatic disease / active hepatitis |
| History of INH-induced hepatitis |
| Concurrent hepatotoxic drugs (without close monitoring) |
| Drug interactions (e.g., rifampicin + anticoagulants, OCPs, antiretrovirals) |
9. PYRIDOXINE (VITAMIN B6) CO-ADMINISTRATION
Given to prevent INH-induced peripheral neuropathy:
- Mandatory in: Pregnancy, PLHIV, DM, alcoholism, malnutrition, CKD, elderly
- Dose: 25–50 mg/day orally
10. NTEP PROGRAM DELIVERY
| Aspect | Details |
|---|---|
| Platform | Delivered through NikshaY portal tracking |
| DOT (Directly Observed Therapy) | Mandatory for 3HP (weekly dosing); encouraged for all regimens |
| Nikshay Poshan Yojana | Nutritional support ₹500/month for TB patients (extends to some TPT recipients) |
| Contact investigation | Systematic tracing of all household/close contacts of index TB cases |
| Cascade | Identify → Screen → Test (if needed) → Initiate TPT → Complete |
11. EFFICACY OF TPT REGIMENS
| Regimen | Efficacy (TB prevention) | Completion Rate |
|---|---|---|
| 6H | ~60–90% | ~60–70% |
| 9H | ~90% | ~60% |
| 3HP | ~89% (non-inferior to 9H) | ~82–90% (highest) |
| 4R | ~80% | ~78% |
| 3HR | Similar to 3HP | ~80% |
3HP has the highest completion rates — major advantage driving NTEP adoption
12. HIGH-YIELD EXAM POINTS (MD/PGMEE)
| Point | Detail |
|---|---|
| TPT formerly called | IPT (Isoniazid Preventive Therapy) |
| NTEP preferred regimen | 3HP (3 months, weekly) |
| INH dose in TPT | 5 mg/kg/day (max 300 mg) |
| TST required for PLHIV? | No — treat empirically after ruling out active TB |
| Age below which all contacts get TPT | < 5 years — all get TPT regardless of TST |
| Pyridoxine dose | 25–50 mg/day with INH |
| Ruling out active TB tool | W4SS (4-symptom screen) |
| Most common side effect of INH | Hepatotoxicity |
| TPT in MDR contact | No standard regimen; fluoroquinolone-based under study |
| TPT in pregnancy | Defer if possible; if PLHIV, use 6H + pyridoxine |
| Duration of standard IPT | 6 months (6H) |
| WHO 2020 new short regimen | 1HP (1 month daily INH + Rifapentine) — conditional |
| End TB strategy pillar | TPT is part of Pillar 1: Integrated TB care and prevention |
13. CLASSIFICATION SUMMARY TABLE
| Regimen | Drugs | Duration | Frequency | WHO Grade |
|---|---|---|---|---|
| 6H | INH | 6 months | Daily | Strong |
| 9H | INH | 9 months | Daily | Strong |
| 3HP | INH + Rifapentine | 3 months | Weekly | Strong |
| 3HR | INH + RIF | 3 months | Daily | Strong |
| 4R | RIF | 4 months | Daily | Strong |
| 1HP | INH + Rifapentine | 1 month | Daily | Conditional |
This covers the full scope of TPT as tested in MD/PGMEE exams under NTEP, WHO guidelines, and Harrison's. Key exam traps: TST not needed for PLHIV, pyridoxine mandatory in high-risk, 3HP is the current NTEP preferred regimen, and all child contacts <5 years receive TPT automatically.
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