PF-00489791 + itraconazole

PF-00489791 + itraconazole is a combination of PF-00489791, an investigational long-acting **phosphodiesterase type 5 inhibitor**, and **itraconazole**, a clinically approved antifungal and potent CYP3A4 inhibitor. PF-00489791 was developed as an oral antihypertensive and for renal protection in diabetic nephropathy, acting primarily by **inhibiting PDE5 to increase cyclic GMP** in vascular smooth muscle, resulting in vasodilation and blood pressure reduction. Itraconazole is primarily used as an antifungal but is frequently used in drug-drug interaction studies to inhibit CYP3A4 and assess pharmacokinetics in combination with investigational agents. No unique clinical indication is established for the specific combination; it is most likely used in clinical pharmacokinetic interaction studies to characterize the metabolic profile and potential DDI (drug-drug interaction) liabilities of PF-00489791, given its metabolism by CYP enzymes. - PF-00489791 itself was developed by Pfizer for diabetic nephropathy, hypertension, Raynaud's disease, renal failure, and other indications, but its clinical development has mostly been discontinued[3][7]. - Itraconazole is developed and marketed by various companies as an antifungal, often leveraged in clinical studies for its strong CYP3A4 inhibition. - The combination has no distinguished clinical brand or formulation for therapeutic use but is of pharmacological research interest for characterizing PF-00489791 metabolism/exposure changes in the presence of itraconazole.