What affects cyclosporine absorption?
Cyclosporine is poorly absorbed from the gut with a bioavailability of 30% though with substantial variability among individuals. A high-fat meal can increase absorption. Grapefruit juice and marmalade from Seville oranges contain dihydroxy-bergamottin, which inhibits the cytochrome P450 enzyme in the small intestine, resulting in increased absorption and decreased metabolism of cyclosporine as well as statins and ACE inhibitors. St. John’s Wort decreases cyclosporine levels by inducing cytochrome P450 3A4, duodenal P-glycoprotein, and MDR-1 gene.