The 3 HP Regime for Tuberculosis Preventive Treatment: Safety, Dosage and Related Concerns during its Large-scale Implementation in Countries like India

Abstract

The 3-month once-weekly isoniazid-rifapentine (3 HP) regime is one of the shorter rifamycin-based regimes for tuberculosis preventive treatment recommended by WHO now being rolled in countries including India. The 3 HP regime has several advantages but has also been associated with a higher frequency of systemic drug reactions (SDRs) including non-specific and usually mild flu-like syndromes. Grade 3 or 4 adverse events like hypotension, dizziness, and bronchospasm resulting in discontinuation of therapy have also been noted. Low BMI is one of the risk factors for SDRs. Available observational data on 3 HP in the Asian region suggests that SDRs were frequent leading sometimes to discontinuation and concerns over large-scale implementation in some studies. 19% (118/614) of household contacts initiated on 3 HP in Delhi reported dizziness. Pharmacokinetic studies suggest that the SDRs may be related to isoniazid and its plasma concentration. This viewpoint article points to the risks of adverse events related to the fixed once-weekly dose of 900 mg across weight bands in adults in the current 3 HP regime, amplified by the acetylator status and the lack of co-administration of pyridoxine; and suggests the way forward to minimise the risk of adverse effects to 3 HP in India.

Note:

Funding Information: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conflict of Interests: None.

Keywords: Tuberculosis preventive treatment, isoniazid, rifapentine

JEL Classification: I19