Pentobarbital increases toxicity of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Keep track of. CYP3A4 inducers may well enhance the metabolism of ifosfamide to its active alkylating metabolites. pentobarbital will lower the extent or influence of tamoxifen by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. pentobarbita... https://sodiumpentobarbitalfordog17394.bloginder.com/22440061/5-essential-elements-for-sodium-pentobarbital-for-dogs