Isoniazid Preventive Therapy [IPT] in People Living with HIV [PLHIV]

Isoniazid Preventive Therapy (IPT) administration in People Living with HIV (PLHIV) prevents the incidence and relapse of TB and is a key public health intervention for TB prevention in PLHIV. Concomitant administration of Anti-retroviral Therapy (ART) and IPT, restores TB-specific immunity and prolongs the beneficial effect of IPT.

Combined use of IPT with ART is recommended for all Children Living with HIV (CLHIV)/ PLHIV regardless of:

• Degree of immunosuppression

• Previous treatment for TB  

• Pregnancy

ART should not be delayed while starting or completing a course of IPT. If there is any doubt about the TB status of a patient, IPT should be delayed.

PLHIV/ CLHIV are offered IPT by the treat-only policy, i.e., tests for TB infections, like Tuberculin Skin Test (TST) or Interferon Gamma Release Assay (IGRA) are not warranted. However, active TB disease must be ruled out before starting IPT.

Ruling Out Active TB

• In adults and adolescents living with HIV: Screen for active TB with a clinical algorithm, for the four symptoms (current cough, night sweats, fever, weight loss). (4S symptom negative, i.e., 4S -ve) identifies PLHIV with a very low probability of having TB disease and who can be reliably initiated on IPT. 

• In CLHIV (more than 12 months of age): Screen for current cough, fever, poor weight gain and history of contact with a TB case. When negative (4S -ve), they are unlikely to have active TB. A chest X-ray may be useful.

• Infants aged <12 months living with HIV who are in contact with a person with TB should undergo clinical evaluation. Those who are unlikely to have active TB should receive TB Preventive Treatment (TPT).

Contraindications to IPT

• Signs and symptoms of peripheral neuropathy such as persistent tingling, numbness and burning sensation in the limbs
• Regular and heavy alcohol consumption
• Active hepatitis
• Concurrent use of other hepatotoxic medications
• Contact with a Multidrug-resistant TB (MDR-TB) case
• PLHIV who have completed DR-TB treatment

IPT Work-up: The patient should be examined for signs of liver disease (jaundice, tenderness in the right upper quadrant of the abdomen) and neuropathy. Wherever available, routine Liver Function Tests (LFTs)/ Alanine Aminotransferase (ALT) should be performed, but a lack of LFTs/ALT results should not delay the initiation of IPT in asymptomatic patients. 

Dosage in Adults and Adolescents: Isoniazid 300 mg + Pyridoxine 50 mg (Vitamin B6) per day x 6 months

Non-availability of pyridoxine should not be a reason to withhold TPT. Alternatively, the multivitamin/ B-complex formulations with the requisite prophylactic dose of pyridoxine may be given.

IPT Initiation and Follow-up

•      All 4S -ve patients should be assessed by the Senior Medical Officer (SMO)/ MO to determine eligibility for IPT. IPT should be considered for both on-ART and pre-ART patients and initiated if not contraindicated. IPT drugs must be provided monthly (30 days) to all eligible patients.
•      In case a patient becomes 4S +ve during the IPT course, he/she should be investigated for TB and if found positive, IPT should be stopped, and appropriate anti-TB treatment should be initiated.

References

• National Guidelines for HIV Care and Treatment, NACO, MoH, GoI, 2021.

• Guidelines for Programmatic Management of Tuberculosis Preventive Treatment in India, WHO, MoHFW, GoI, 2021.

Assessment