Unit 5: IPTUnit 5: IPTIsoniazid TB Preventive Therapy Isoniazid TB Preventive Therapy

Botswana National Tuberculosis Programme Manual Training for Medical Officers

Slide 5-2Unit 5: IPT: Isoniazid TB Preventive Therapy

ObjectivesObjectives

At the end of this unit, participants will be able to:

• Describe the role of INH Preventive Therapy (IPT) for HIV-infected persons with latent TB infection

• Describe how to appropriately screen eligible patients for IPT

Slide 5-3Unit 5: IPT: Isoniazid TB Preventive Therapy

IPT: Isoniazid Preventive TherapyIPT: Isoniazid Preventive Therapy

• Type of secondary prevention

• To prevent development of active TB in HIV positive individuals in whom active TB has been excluded

• 6-month course of INH

Slide 5-4Unit 5: IPT: Isoniazid TB Preventive Therapy

Rationale for IPTRationale for IPT

• 10% lifetime risk of developing active TB if infected with M. tuberculosis alone

• 5-10% annual risk of developing active TB if co-infected with HIV

• IPT is meant to prevent progression of latent TB to active disease

• INH shown to decrease incidence of TB among HIV- infected persons by about 40%• The protection period ranges from <1 year to 3 years*

Source: BNTP Manual, 2007.

Slide 5-5Unit 5: IPT: Isoniazid TB Preventive Therapy

Rationale for IPT in BotswanaRationale for IPT in Botswana

• HIV prevalence is 17.1% in general population*• TB case rate increased ~ 3-fold in 1990s**

• 1989: 199 /100,000• 2002: 623 /100,000

• ~80% of adult TB cases are HIV co-infected***• Patients more likely to seek HIV testing if they would receive

health benefit such as IPT and ART (1999 KABP study in Botswana)

Sources: *HIV Medicine Association, et al., 2007 ** BNTP Manual, 2007. ***BIASII, 2004

Slide 5-6Unit 5: IPT: Isoniazid TB Preventive Therapy

IPT EffectivenessIPT Effectiveness

Overall 55% reduction in TB incidence

Source: Churchyard GJ, Fielding K, et al., Aurum Health Research, 2003.

South African Miners, 2003

IPT usage TB incidence

IPT (n=338) 8.6/100 person years

No IPT (n=221) 19.1/100 person years

Slide 5-7Unit 5: IPT: Isoniazid TB Preventive Therapy

IPT Effectiveness Related to ARTIPT Effectiveness Related to ART

TB Incidence in 11,026 HIV-infected patients in Brazil

76% reduction with both INH and ART when adjusted for age, previous TB diagnosis and CD4 count at baseline

Source: Golub JE, et al., Johns Hopkins University 2007.

No INH Yes INH

No ART4.01/100

person years1.27/100

person years

Yes ART1.90/100

person years0.80/100

person years

Slide 5-8Unit 5: IPT: Isoniazid TB Preventive Therapy

Assessment for IPTAssessment for IPT

• Medical and social history• Previous exposure to TB• Previous treatment for TB• HIV positive

• TB Screening questions

• Physical examination

• Clinical evaluation of TB suspects• Sputum smear for microscopy and other

investigations as indicated

Slide 5-9Unit 5: IPT: Isoniazid TB Preventive Therapy

Screening QuestionsScreening Questions

• Cough for 2-3 weeks• Weight loss• Night sweats• Fever• Malaise• Shortness of breath• Chest pain• Haemoptysis

Consider EPTB:• Lymphadenopathy• Headache• Abdominal pain or

distension• Swollen joints• Backache

Slide 5-10Unit 5: IPT: Isoniazid TB Preventive Therapy

Mohammed A, et al. Int J Tuberc Lung Dis, 2004.

TB Screening Tests in TB Screening Tests in Patients with Advanced HIV DiseasePatients with Advanced HIV Disease

Slide 5-11Unit 5: IPT: Isoniazid TB Preventive Therapy

Signs / symptoms of PTB

YES

NO

INITIATE IPT

Sputum microscopy x 3

for AFB

TREAT FOR TB

CXR & assessment

Treat for bacterial

infection Good response

Poor response

All negative

ONE positive

TB unlikely

TB likely

Screening Algorithm for IPTScreening Algorithm for IPT

Slide 5-12Unit 5: IPT: Isoniazid TB Preventive Therapy

IPT Drugs and DosagesIPT Drugs and Dosages

• Recommended daily dosage:

• INH:

• Adults: 5 mg/kg/day, 300 mg/day max

• Children: 10-20 mg/kg/day, 300 mg/day max

• Pyridoxine (B6) co-administered: • 25mg orally, daily

Slide 5-13Unit 5: IPT: Isoniazid TB Preventive Therapy

Preventing Isoniazid Resistant TBPreventing Isoniazid Resistant TB

• Constant & proper use of the algorithm for the dx of PTB to prevent monotherapy

• Screening of patients at each visit

• Thorough investigation of those suspected of having TB

• Ongoing counselling of patients to maintain adherence

Slide 5-14Unit 5: IPT: Isoniazid TB Preventive Therapy

Emergence of Resistance with Emergence of Resistance with Single Drug Therapy of Active TBSingle Drug Therapy of Active TB

Start INH alone

0

12

3

4

56

7

8

0 2 4 6 8 10 12 14 16 18 20 22 24Weeks of Therapy

Log

cfu

INH-Sensitive

INH-Resistant

Slide 5-15Unit 5: IPT: Isoniazid TB Preventive Therapy

Reasons to Stop IPTReasons to Stop IPT

• Patient misses 2 consecutive monthly refill/monitoring appointments

• Develops INH intolerance (serious side effect)• Becomes terminally ill• Potentially stop if female patient becomes pregnant

• If less than 3 months of IPT, discontinue• If more than 3 months of IPT, continue treatment

• Develop symptoms of active TB

Slide 5-16Unit 5: IPT: Isoniazid TB Preventive Therapy

Patient Education PointPatient Education Point

• Ensure HIV positive patients understand the benefits of IPT (55% reduction in TB disease)

• Reinforce information at each visit• Assess adherence to therapy, as with TB treatment• Patients should be taught to recognize signs &

symptoms of active TB• Discuss side-effects and support patient by problem

solving ways to manage minor SEs• Encourage questions

Unit 5: Infection Control and Prevention of TB

Slide 5-17Unit 5: IPT: Isoniazid TB Preventive Therapy

Key PointsKey Points

• It is important to appropriately screen for signs & symptoms of TB in HIV positive individuals before initiating IPT

• HIV positive individuals have a 5-10% chance of developing active TB per year

• IPT can prevent TB disease in HIV positive individuals