Ritonavir interaction with quinine is clinically insignificant but may warrant caution
1 November 2012. Related: PK and drug interactions.
Coadministration of ritonavir (100 mg twice daily) and quinine (105.3, 162, 210.6 or 648 mg single doses) was studied in 4 groups of HIV negative subjects (n=20 per group).
Quinine did not have a significant effect on ritonavir Tmax or Cmax, but increased AUC from 9.2 ± 2.21 ug.h/ml to 11.1 ± 3.96 ug.h/ml.
Similarly, ritonavir had no significant effect on quinine pharmacokinetics (Cmax 4.3 ± 1.07 vs 3.9 ± 0.88 ug/ml, AUC 78.9 ± 26.78 vs 68.4 ± 22.29 ug.h/ml, alone vs with ritonavir). Although the increased ritonavir exposure and decreased quinine exposure are unlikely to be of clinical significance, caution should be exercised if coadministered.
Source: hiv-druginteractions.org (31 July 2012).
Wason S et al. Lack of clinically significant pharmacokinetic interactions between quinine and ritonavir in healthy adult participants. International Workshop on Comorbidities and Adverse Drug Reactions in HIV, Washington, July 2012. Abstract P21.