Which short-course latent TB regimen includes weekly dosing?

• A. 6 months of isoniazid (6H).
• B. 12 weeks of weekly isoniazid plus rifapentine (3HP).
• C. 4 months of rifampin.
• D. 9 months of isoniazid.

Answer: (B)

Weekly dosing is achieved with a short-course latent TB regimen that combines isoniazid with rifapentine and is given once weekly for 12 weeks. This regimen, often called 3HP, leverages rifapentine’s longer half-life to maintain effective drug exposure with fewer dosing events, so you complete the course in about three months instead of many months of daily pills. The other options require daily dosing for longer periods: isoniazid alone daily for six or nine months, or rifampin daily for four months. The weekly schedule can improve adherence and completion rates in suitable patients, though drug interactions and certain contraindications with rifapentine require clinical consideration.