The invention concerns safe non-interacting drug combinations of a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, which is (E)-7-[4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)a- mino]pyrimidin-5-yl] (3R,5S)-3,5-dihydroxyhept-6-enoic acid or a pharmaceutically acceptable salt thereof (the Agent) and a drug which is either an inducer, inhibitor or a substrate of cytochrome P450, in particular cytochrome P450 isoenzyme 3A4. Particular combinations are useful in treating hyperlipidaemia in humans who are receiving immunosuppressive chemotherapy. A preferred combination is the Agent and a fibrate drug, the use of such a combination in treating hyperlipidaemia in mammals, and medicaments containing such a combination for use in such treatments.