From the Guidelines
Rifapentine is a rifamycin derivative antibiotic used to treat tuberculosis, primarily in combination therapy for both active and latent TB infection, with a common regimen being once-weekly rifapentine (900 mg) plus isoniazid (900 mg) for 12 weeks, known as the 3HP regimen 1.
Key Characteristics of Rifapentine
- It works by inhibiting bacterial RNA synthesis, targeting the beta subunit of bacterial DNA-dependent RNA polymerase, which prevents bacterial growth.
- Rifapentine has a longer half-life than rifampin, allowing for less frequent dosing.
- Common side effects include reddish-orange discoloration of body fluids, liver enzyme elevations, rash, and gastrointestinal disturbances.
Use in Latent TB Infection
- A preferred regimen for latent TB is 3 months of once-weekly isoniazid plus rifapentine, strongly recommended for adults and children aged > 2 years, including HIV-positive persons, as long as drug interactions allow 1.
- This regimen has equivalent effectiveness to the standard 9 months of daily isoniazid, with higher treatment completion rates and less hepatotoxicity in some populations.
Considerations for Use
- Patients should be advised that rifapentine can reduce the effectiveness of hormonal contraceptives and many other medications through enzyme induction.
- Regular liver function monitoring is recommended during treatment, and patients should avoid alcohol to reduce the risk of liver toxicity.
- Potential disadvantages of the 3HP regimen include cost, the need to take numerous pills simultaneously, and the association with a systemic drug reaction or influenza-like syndrome, although severe events are rare and self-limited 1.
From the FDA Drug Label
Rifapentine is a rifamycin derivative antimicrobial and has a similar profile of microbiological activity to rifampicin. Rifapentine is a rifamycin derivative antimicrobial.
- It has a similar profile of microbiological activity to rifampicin.
- The molecular weight is 877.04.
- The molecular formula is C47H64N4O12.
- The chemical name for rifapentine is rifamycin, 3-[[(4-cyclopentyl-1-piperazinyl)imino]methyl]- or 3-[N-(4-cyclopentyl-1-piperazinyl)formimidoyl] rifamycin or 5,6,9,17,19,21-hexahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-8-[N-(4-cyclopentyl-l-piperazinyl)-formimidoyl]-2,7-(epoxypentadeca1, 11, 13trienimino)naphtho[2,1-b]furan-1,11(2H)-dione 21-acetate 2 2
From the Research
Definition and Mechanism of Rifapentine
- Rifapentine is a rifamycin derivative used in the treatment of latent tuberculosis infection (LTBI) 3, 4, 5, 6, 7.
- It has a potent sterilizing effect against Mycobacterium tuberculosis and a long half-life, making it an attractive option for LTBI treatment 5.
Efficacy of Rifapentine
- Rifapentine in combination with isoniazid for 12 weeks is considered the best available option for treating latent TB in the majority of patients in the United States due to its favorable safety profile and increased likelihood of completing therapy 5.
- A 3-month regimen of rifapentine and isoniazid has been shown to be as effective as 9 months of isoniazid alone in preventing tuberculosis, with a higher treatment-completion rate 6.
- Rifapentine alone has also been predicted to result in equal or better efficacy than combination regimens for LTBI treatment without the potential added toxicity of isoniazid 4.
Treatment Regimens and Completion Rates
- Once-weekly isoniazid and rifapentine for 12 doses is an effective treatment regimen, but its effectiveness can be limited by requiring direct observation 3.
- Self-administered therapy with rifapentine and isoniazid has been shown to be noninferior to direct observation in the United States, with treatment completion rates of 74.0% to 76.4% 3.
- The 3-month isoniazid-rifapentine regimen has been associated with higher treatment completion rates (87.5%) compared to other LTBI regimens (65.9%) 7.