Cadazolid, a novel antibiotic with potent activity against Clostridium difficile: safety, tolerability and pharmacokinetics in healthy subjects following single and multiple oral doses

Results: Cadazolid was well tolerated up to 3000 mg given twice daily for 10 days. The most common adverse event was headache, with no observed relationship between dose or treatment duration and adverse events. Plasma concentrations of cadazolid were low. No plasma concentrations .3.3 ng/mL were observed after single doses or .6.9 ng/mL after 10 days of multiple doses. Food increased the mean Cmax from 0.73 to 1.87 ng/mL and mean AUC 0– t from 3.13 to 15.69 ng . h/mL after a single 300 mg dose. The increase in systemic exposure to cadazolid across doses was less than dose-proportional. The mean cumulative faecal recovery was 81.0% – 93.5%. Urinary recovery of unchanged compound was ,0.015%. Conclusions: Cadazolid was well tolerated and its systemic exposure was low. The majority of compound was recovered unchanged in the faeces, thus resulting in high concentrations at the site of action (colon).