CYP3A4 and Hypertension: In some individuals, additional antihypertensive medications may be required to control hypertension [175]. If such is the case, non-dihydropyridine calcium channel blockers (e.g., verapamil and diltiazem) should not be used in combination with cytochrome P450 3A4 (CYP3A4) isoenzyme inhibitors (e.g., sorafenib), due to the risk of markedly increased concentrations of the chemotherapeutic agent.