Clarithromycin

Clarithromycin has a broad spectrum of antimicrobial activity. Clarithromycin inhibits the CYP3A4-catalyzed triazolam alpha-hydroxylation with the IC₅₀ (K_i) value of 56 (43) μM^[2]. Clarithromycin significantly inhibits the HERG potassium current^[3].Clarithromycin affects the autophagic flux by impairing the signaling pathway linking hERG1 and PI3K^[4]. In Vitro: Clarithromycin produces a similar concentration-dependent block with an IC₅₀ of 45.7 µM^[3].
Clarithromycin induces the formation of numerous intracytoplasmic vacuoles after 24 h, in all cell lines, especially in HCT116 cells. Prolonged treatment with Clarithromycin (40, 80, and 160 µM) alters cell proliferation and triggers apoptotic cell death in colorectal cancer (CRC) cells. Inhibition of cell proliferation is potentiated when Clarithromycin is re-added to the cells. In particular, 160 μM Clarithromycin, re-added after 48 h of incubation, produces an arrest of cell proliferation at 72 h. Similar effects are obtained in LS174T cells^[4].
Clarithromycin (80 and 160 µM; 48 hours) strongly increases the LC3-II/LC3-I ratio, in a dose- and time-dependent manner, with a maximum at 24 h of treatment. This effect is accompanied by a decrease of p62/SQSTM1^[4].
In Vivo: Clarithromycin at 200 mg/kg has activity against four tested in vivo^[5].