Skip to main content
Figure 2 | Annals of Clinical Microbiology and Antimicrobials

Figure 2

From: Osteomalacia in an HIV-infected man receiving rifabutin, a cytochrome P450 enzyme inducer: a case report

Figure 2

Schematic diagram of vitamin D metabolism and cytochrome P450 mediated drug effects. Cytochrome P450 enzyme inhibition is indicated by broken lines and stimulation by solid lines. The strength of enzyme inhibition or stimulation is indicated by the width of the lines and the number of terminal plus or minus signs. As the differential effects of rifabutin on the vitamin D hydroxylase enzymes have not been reported, our prediction of the action of rifabutin is shown, which might be mediated by SXR. Ritonavir also can bind to SXR which might induce 24-hydroxylase activity, but in vitro ritonavir appears to inhibit rather than stimulate 24-hydroxylase. Abbreviations: 7DHC 7-dehydrocholesterol; 25OHase 25-hydroxylase; 25OHD3 25-hydroxyvitamin D3; 1OHase 1α-hydroxylase; 1,25(OH)2D3 1,25-dihydroxyvitamin D3; VDR vitamin D receptor; 24OHase 24-hydroxylase; SXR steroid and xenobiotic receptor.

Back to article page