What are the differences between rifampicin and rifapentine?

Rifampicin and rifapentine are both commonly used anti-tuberculosis drugs. Their core differences lie in aspects such as dosing frequency, antimicrobial activity, half-life, applicable populations, and adverse reactions. A detailed analysis is as follows:

1. Dosing frequency: Rifampicin requires daily administration, typically once a day, and must be taken regularly over a long period to maintain therapeutic efficacy. Rifapentine has a more prolonged antimicrobial effect and thus a lower dosing frequency, usually administered 1–2 times per week, which improves patient adherence to treatment.

2. Antimicrobial activity: Rifampicin has a clear bactericidal effect against Mycobacterium tuberculosis and is a first-line foundational drug for tuberculosis treatment. Rifapentine is a derivative of rifampicin with stronger antimicrobial activity. In vitro studies show its inhibitory effect on Mycobacterium tuberculosis is 2–10 times greater than that of rifampicin, resulting in superior bactericidal performance.

3. Half-life: Rifampicin has a relatively short half-life of approximately 3–5 hours, leading to rapid metabolism in the body and necessitating daily dosing to maintain effective blood concentrations. In contrast, rifapentine has a much longer half-life of 13–17 hours, allowing for prolonged drug action and providing a pharmacological basis for reduced dosing frequency.

4. Applicable populations: Rifampicin has a broad application range and can be used in various tuberculosis patients, including those undergoing initial treatment, retreatment, or tuberculosis prophylaxis. Due to its long-acting properties, rifapentine is more suitable for use during the consolidation phase of treatment and for patients unable to adhere to daily medication regimens. However, it should be used with caution in pregnant women and patients with severe liver dysfunction.

5. Adverse reactions: Both drugs may cause liver function abnormalities. Rifampicin has a relatively higher incidence and commonly causes gastrointestinal discomfort and rashes. Rifapentine generally has milder side effects, with lower rates of hepatotoxicity and gastrointestinal reactions compared to rifampicin. Some patients may experience rashes or leukopenia.

Medication must strictly follow medical instructions. The appropriate drug should be selected based on individual conditions and health status, with regular monitoring of liver function and other indicators to ensure safe and effective treatment.