QCan you use sarecycline for other tetracycline responsive diseases like Lyme disease and MRSA?

Sarecycline is a narrow-spectrum tetracycline oral antibiotic FDA-approved in 2018 to treat moderate-to-severe acne vulgaris in patients 9 years old or older. The intention in the development of this drug was to optimize the anti-inflammatory effects of tetracyclines while minimizing the potential development of antiobiotic resistance and reducing gastrointestinal side effects of the tetracycline class¹. Although sarecycline was found to be equally effective against MRSA, sarecycline is considered a narrow spectrum antibiotic with four- to eight-fold less activity against normal human microbiota than other tetracyclines.² Phase I studies did not show any differences in bioavailability with and without food compared to other tetracyclines.³ Phototoxicity has been reported although with low frequency in only 0.2% of patients.⁴

Based on the effects of tetracyclines as a class against MRSA and lyme disease (Borrelia spp), the beneficial effects of sarecycline therapy for conditions caused by these bacteria are theoretically sound. However, oral sareclycine has not received approval for the treatment of MRSA or Lyme disease from the FDA. Therefore, I do not recommend the use of sarecycline as a therapeutic agent against MRSA or Lyme disease.

References:

1. Moore et al. Future Microbiol. 2019
2. Zhandel et al. Antimicrob. Agents Chemother. 2019
3. US FDA Review. 2018