Effect on tacrolimus when switching from nelfinavir to fosamprenavir

9 February 2009. Related: PK and drug interactions.

This case report outlines the change in tacrolimus trough blood concentrations when 4 HIV-infected orthotopic liver transplant patients were switched from nelfinavir (1250 mg twice daily) to fosamprenavir (1400 mg twice daily without ritonavir) due to the EMEA ruling on nelfinavir in June 2007.

After the switch, tacrolimus trough concentrations dropped significantly (>50%) and a marked dosage increase was required to attain the desired target concentration. The cases highlight the need for caution in immunosuppressed patients when switching or starting a protease inhibitor.

Reference:
Pea Fet al. Drop in trough blood concentrations of tacrolimus after switching from nelfinavir to fosamprenavir in four HIV-infected liver transplant patients. Antivir Ther, 2008, 739-742.
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