Coadministration had no effect on raltegravir AUC or Cmax, but decreased C12 by 30%. There was no change in lopinavir pharmacokinetics. No dose adjustment is necessary.

Drug interaction studies reveal no clinically significant interaction between Kaletra and raltegravir. 

The interaction between raltegravir (400 mg twice daily) and lopinavir/ritonavir (400/100 mg twice daily) was determined in 12 HIV- subjects. Lopinavir had no effect on raltegravir AUC or Cmax (5.3 vs 5.4 mg/L.h and 1698 vs 1687 ng/ml, alone vs combination respectively) but decreased raltegravir Cmin by 30% (49.4 vs 34.4 ng/ml). Lopinavir and ritonavir pharmacokinetics were similar when given alone or with raltegravir. Despite a decrease of 30%, raltegravir Cmin remained above the estimated IC95 of 15 ng/ml, suggesting that raltegravir and lopinavir/ritonavir can be coadministered without dose adjustments of either drug.